-
0.16
0.76
1.62
2.61
-
-
0.03
0.27
0.87
Xaraés
-
0.08
0.71
1.00
1.86
-
-
0.01
0.15
0.80
Mean
-
0.11
0.84
1.43
2.26
-
-
0.03
0.21
0.76
LSD1
-
0.07
0.37
0.82
0.95
-
-
0.02
0.10
0.22
LS2
-
<0.001
0.005
0.127
0.068
-
-
<0.001
<0.001
0.001
1Least Significant Difference (Tukey P≤0.05).
2Level of significance.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Brachiaria spp. evaluation in Ecuador 71
Table 5. Plant height at different ages of regrowth of 5 Brachiaria cultivars during the rainy (March‒May) and dry (September‒
November) seasons in humid tropical conditions of Ecuador.
Cultivar
Plant height (cm)
Rainy season
Dry season
Age of regrowth (weeks)
Age of regrowth (weeks)
2
4
6
8
10
2
4
6
8
10
Señal
43.1
53.5
81.8
95.4
80.2
29.6
42.5
70.4
91.3
77.5
Marandú
40.3
48.8
77.2
117.1
129.8
32.4
30.0
41.5
55.0
67.8
Mulato II
47.7
57.3
83.5
108.3
129.2
32.5
31.2
43.1
57.9
75.8
Piatá
45.8
63.8
98.8
132.1
137.1
32.0
39.2
65.7
95.4
105.5
Xaraés
54.5
71.6
91.2
126.3
137.8
32.3
48.3
71.0
91.3
103.5
Mean
46.3
59.0
86.5
115.8
122.8
31.8
38.2
58.4
78.2
86.0
LSD1
9.4
10.6
14.3
10.1
19.8
10.1
9.1
16.5
16.8
23.8
LS2
0.005
0.001
0.003
<0.001
<0.001
0.879
<0.001
<0.001
<0.001
<0.001
1Least Significant Difference (Tukey P≤0.05).
2Level of significance.
Leaf area index
the lowest SLA throughout the wet season, while Señal,
Mulato II and Marandú presented the highest values. In
During the rainy season, the leaf area index (LAI)
the dry season, cultivar differences again emerged with
followed a linear pattern for all cultivars, increasing from
Mulato II, Marandú and Señal having the greatest SLA
a mean of 0.6 at week 2 to 5.3 at week 10 (Table 6). The
and Xaraés and Piatá the lowest (P<0.01).
cultivars Mulato II and Xaraés reached the highest LAI at
week 10 of 6.6 and 5.8, respectively. Throughout the wet
Crude protein concentration
season Piatá had lower LAI than most other cultivars
(P<0.001). During the dry season, LAI followed an
Data for weeks 4, 6 and 8 on whole plant samples are
exponential pattern with the highest increase from the
presented in Table 8. Differences in crude protein
sixth week. As for the wet season, Piatá showed lower
concentration (P<0.05) between cultivars were observed
LAI than Xaraés and Mulato II by week 10 (P<0.05).
in both rainy and dry seasons, where Mulato II presented
the highest concentration at most observations. In both
Specific leaf area
seasons, mean crude protein concentration decreased as
the regrowth age increased, declining from 14.1% to 9.1%
Specific leaf area (SLA) declined in all cultivars during
in the wet season and from 12.6% to 7.6% in the dry
both rainy and dry seasons (Table 7). Piatá tended to have
season.
Table 6. Leaf area index at different ages of regrowth of 5 Brachiaria cultivars during the rainy (March‒May) and dry (September‒
November) seasons in humid tropical conditions of Ecuador.
Cultivar
Leaf area index
Rainy season
Dry season
Age of regrowth (weeks)
Age of regrowth (weeks)
2
4
6
8
10
2
4
6
8
10
Señal
0.5
2.0
3.2
3.7
5.1
0.4
0.9
1.2
2.7
4.8
Marandú
0.6
1.8
3.1
4.3
5.4
0.7
1.0
1.6
2.5
4.4
Mulato II
0.8
2.6
3.8
4.7
6.6
0.3
0.8
1.4
3.6
5.8
Piatá
0.5
1.3
2.1
3.4
3.8
0.3
0.7
1.4
2.2
3.6
Xaraés
0.7
1.9
3.5
4.9
5.8
0.3
0.9
1.6
3.6
5.9
Mean
0.6
1.9
3.1
4.2
5.3
0.4
0.9
1.4
2.9
4.9
LSD1
0.2
0.4
1.0
1.1
1.2
0.2
0.2
0.3
0.9
2.2
LS2
0.001
<0.001
0.002
0.004
<0.001
<0.001
0.045
0.016
0.001
0.03
1Least Significant Difference (Tukey P≤0.05).
2Level of significance.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
72 J.R. Garay, S. Joaquín, P. Zárate, M.A. Ibarra, J.C. Martínez, R.P. González and E.G. Cienfuegos
Table 7. Specific leaf area at different ages of regrowth of 5 Brachiaria cultivars during the rainy (March‒May) and dry (September‒
November) seasons in humid tropical conditions of Ecuador.
Cultivar
Specific leaf area (cm2/g)
Rainy season
Dry season
Age of regrowth (weeks)
Age of regrowth (weeks)
2
4
6
8
10
2
4
6
8
10
Señal
229
246
181
190
151
248
232
173
163
164
Marandú
242
216
168
163
145
273
221
213
158
162
Mulato II
268
190
187
165
162
238
279
210
178
168
Piatá
156
129
125
124
112
221
173
148
125
112
Xaraés
207
148
134
130
132
237
213
170
142
129
Mean
221
186
159
154
140
243
224
183
153
147
LSD1
29
30
41
40
34
85
39
25
28
27
LS2
<0.001
<0.001
0.001
0.001
0.005
0.433
<0.001
<0.001
<0.001
<0.001
1Least Significant Difference (Tukey P≤0.05).
2Level of significance.
Table 8. Crude protein concentration at different ages of regrowth of 5 Brachiaria cultivars during the rainy (March‒May) and dry (September‒November) seasons in humid tropical conditions of Ecuador.
Cultivar
Crude protein concentration (%)
Rainy season
Dry season
Age of regrowth (weeks)
Age of regrowth (weeks)
4
6
8
4
6
8
Señal
13.4
11.2
9.0
11.6
7.3
6.5
Marandú
14.0
12.1
8.8
13.4
8.6
8.1
Mulato II
14.6
12.5
10.1
14.3
10.1
10.2
Piatá
13.8
10.9
8.9
12.2
8.3
6.8
Xaraés
14.6
11.1
8.6
11.6
7.4
6.5
Mean
14.1
11.6
9.1
12.6
8.3
7.6
LSD1
0.9
1.1
0.8
0.9
1.3
3.4
LS2
0.007
0.003
0.001
<0.001
<0.001
0.022
1Least Significant Difference (Tukey P≤0.05).
2Level of significance.
Discussion
The absence of cultivar differences in total DM
production during the rainy season in this study was
This plot study has provided useful information on the
similar to the findings of Rojas-Hernández et al. (2011)
potential of the Brachiaria cultivars for use in pastures of
for B. decumbens, B. brizantha cv. Libertad, B. hybrid
humid tropical Ecuador. While the grasses were planted
cv. Mulato I and cultivars of B. humidicola. Those authors
from seed, were only 12 weeks old at commencement of
also failed to demonstrate any significant differences in
observations and the study was in only a single year, the
total DM production. However, the differences we
excellent growth obtained and CP levels maintained
showed in proportions of leaf and stem in the different
indicate that these pastures can be very productive under
cultivars are important, as we showed higher production
these conditions. In fact, the DM yields obtained over
of leaves and higher CP concentration than Reyes-Purata
only 10 weeks in pastures that were only 12 weeks old at
et al. (2009). The reduction in growth in these cultivars
commencement are quite remarkable. Further studies
during the dry season was not surprising, as the major
under field conditions would clarify how well these
climatic factors that determine forage production are
preliminary findings can be extrapolated to commercial
precipitation and temperature (Gerdes et al. 2000;
situations.
Cuadrado et al. 2004). Rainfall in the rainy season and
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Brachiaria spp. evaluation in Ecuador 73
hence soil moisture was much higher than in the dry
The differences among cultivars for LAI may be
season and minimum temperatures were also lower in the
because some species such as B. decumbens are shorter
dry season. The reduction in TDM yield in the dry season
than B. brizantha, and there is a positive correlation
was somewhat lower than the 50% reduction reported by
between plant height and LAI (Guenni et al. 2005). In
Benítez et al. (2007). This marked reduction in yield
addition, LAI increases as the plant grows (Gómez-
accompanied by a drop in CP concentration indicates the
Carabalí et al. 1999), and this increase is closely related
reduced carrying capacity of these pastures during the dry
to tillering of the crop and soil cover (Rincón et al. 2007;
season.
Ramírez-García et al. 2012). Therefore, as LAI of the
The differences between cultivars in leaf DM yield we
pasture increases, the amount of light that reaches the
found in this study may be due to B. decumbens and
ground will be reduced, which can prevent or retard weed
B. brizantha having different rates of elongation in leaves
growth.
(Dias-Filho and Carvalho 2000). In this regard,
Furthermore, it has been reported that SLA in
elongation rates in leaves of 2.5 and 3.5 cm/d and leaf
Brachiaria cultivars varies according to species; Baruch
percentages in total DM of 54 and 77% in B. decumbens
and Guenni (2007) reported that at 4 weeks of age SLA in
and B. brizantha, respectively, have been reported by
B. decumbens and B. brizantha were 300 and 270 cm2/g,
Guenni et al. (2005). In addition, Hare et al. (2009)
respectively. Also, it has been reported that, as the height
reported that Xaraés and Mulato II have higher foliar
and age of the plant increase, SLA decreases (Gómez et
DM yields than other Brachiaria cultivars, especially
al. 2012), as it did in our study, because there is an
during the dry season. Similarly, Gerdes et al. (2000)
increment in the thickness of the leaves. Grasses with
reported a significant decrease in the accumulation of
greater SLA have thinner leaves and higher concen-
total DM during the period of minimum precipitation,
trations of nitrogen (Pérez et al. 2004) and higher rates of
with as much as 98% of the accumulation corresponding
photosynthesis (Reich et al. 1997), while a high SLA is
to leaf DM.
related to greater palatability and consumption by animals
The pattern of stem DM accumulation during both
(Lloyd et al. 2010; Zheng et al. 2014).
periods would have been determined by environmental
The CP values obtained in this study for Señal
conditions that affected growth of the cultivars. Stem
were higher than those reported by Alvarado et al. (1990)
production during the dry season is reduced (Cab et al.
at 6 and 9 weeks of age (9.4 and 8.8%, respectively),
2008) due to stress caused by soil moisture deficiency,
while the values obtained in Mulato II were similar to
curbing the growth of the plant and reducing stem growth
those found by Castillo et al. (2006) at 3 weeks (15%).
(Cruz et al. 2011a). Cruz et al. (2011b) reported that
The values obtained in Xaraés, Marandú and Piatá were
season has a marked effect on the relative growth of leaf
similar during the rainy season to, and higher in the dry
and stem, and differences between stem elongation rates
season than, those obtained by Pérez et al. (1999) in
of 1.2, 0.8 and 0.6 mm/stem/d in Señal, Xaraés and
B. brizantha at 6 and 9 weeks (11.9 and 8.6%,
Marandú, respectively, have been reported by Paciullo et
respectively). Water deficiency stress can have a negative
al. (2011). The marked reduction in stem growth in the
effect on Brachiaria cultivars, decreasing the con-
dry season results in increases in leaf:stem ratios in this
centration of CP. In this regard, Cuadrado et al. (2004)
season as found in this study. Leaf:stem ratios also
reported that at 24 days of regrowth CP concentration in
declined significantly as plants matured and the
the wet season was higher than in the dry season for
proportion of stem in the forage increased.
Marandú (10.5 vs. 9.3%), Señal (15.4 vs. 9.2%) and
Plant height was affected to a greater extent by
Xaraés (11.5 vs. 8.2%). Increasing age of the plant also
seasonal conditions than by cultivar. Marandú has been
decreases the concentration of CP in forage because of
shown to be quite susceptible to stress caused by soil
accumulation of dry matter (resulting in dilution of
water deficiency, presenting taller plants in the rainy
nutrients), increase in stem DM and decline in the
season (67 cm) and shorter ones in the dry season (36 cm)
proportion of leaf (Juárez-Hernández et al. 2004; Reyes-
at 35 d of regrowth (Gerdes et al. 2000). On the other
Purata et al. 2009), as shown in our study. All cultivars
hand, B. decumbens presented lower height, due to its
had CP concentrations above 7% which is considered the
decumbent growth habit, which is characteristic of this
minimum, below which intake by ruminants could be
species (Pérez et al. 1999). In this study, B. brizantha
suppressed (Lazzarini et al. 2009). The choice of cultivar
cultivars were taller than the Brachiaria hybrid and B.
to use could depend on a range of factors including DM
decumbens, which agrees with what was reported by
yield of leaf, CP concentration, rate of regrowth, response
Gómez et al. (2000).
to fertilizer etc.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
74 J.R. Garay, S. Joaquín, P. Zárate, M.A. Ibarra, J.C. Martínez, R.P. González and E.G. Cienfuegos
Conclusions
Avellaneda C; Cabezas JF; Quintana G; Luna R; Montañez O;
Espinoza I; Zambrano S; Romero D; Vanegas J; Pinargote
While the dry season negatively affected the production
E. 2008. Comportamiento agronómico y composición
and nutritional value of forage of all grasses evaluated, the
química de tres variedades de Brachiaria en diferentes
edades de cosecha. Ciencia y Tecnología 1:87‒94.
most outstanding cultivars in terms of leaf yield, leaf area
index and specific leaf area were: Mulato II, Marandú and
Baruch Z; Guenni O. 2007. Irradiance and defoliation effects in
Xaraés. Xaraés certainly showed the best tolerance of dry
three species of the forage grass Brachiaria. Tropical
conditions, while performing well in terms of total DM
Grasslands 41:269‒276. https://goo.gl/ttgvtU
and leaf production in the rainy season. However, Mulato
Benítez D; Fernández JL; Ray J; Ramírez A; Torres V; Tandrón
II showed high DM yield and nutritional value over time,
I; Díaz M; Guerra J. 2007. Factores determinantes en la
which supports its further evaluation in grass production
producción de biomasa en tres especies de pastos en
systems in humid tropical conditions, especially as good
sistemas racionales de pastoreo en el Valle del Cauto, Cuba.
CP levels (11‒14%) were maintained for long periods in
Revista Cubana de Ciencia Agrícola 41:231‒235.
both rainy and dry seasons. This was a plot study and
plants were only 12 weeks old when observations
Cab F; Enríquez J; Pérez J; Hernández A; Herrera J; Ortega E;
commenced, but the results do indicate that all cultivars
Quero A. 2008. Potencial productivo de tres especies de
performed well and further evaluation of the more
Brachiaria en monocultivo y asociadas con Arachis pintoi
promising cultivars under field conditions, particularly
en Isla, Veracruz. Técnica Pecuaria en México 46:317–332.
under grazing, is warranted.
Cardona C; Sotelo G; Miles JW. 2006. Resistencia en
Brachiaria a especies de salivazo: Métodos, mecanismos y
avances. Pasturas Tropicales 28(1):30‒35. https://goo.gl/
Acknowledgments
Castillo MS; Vélez M; Rosas JC; Trabanino R. 2006.
We thank the Consejo Nacional de Ciencia y Tecnología
Producción y composición de los cultivares Mulato I y II de
(CONACYT) for the grant that made possible the stay of
Brachiaria híbrido inoculados con micorriza y Trichoderma
the first author in Ecuador. Our thanks to the Universidad
harzianum. Ceiba 47:25‒32. DOI: 10.5377/ceiba.v47i1-
Tecnológica Equinoccial, Campus Santo Domingo
(Ecuador) and the Facultad de Ingeniería y Ciencias of the
Cruz PI; Hernández A; Enríquez JF; Mendoza SI; Quero AR;
Universidad Autónoma de Tamaulipas (Mexico) for the
Joaquín BM. 2011a. Desempeño agronómico de genotipos
facilities provided to make this research possible.
de Brachiaria humidicola (Rendle) Schweickt en el trópico
húmedo de México. Revista Fitotecnia Mexicana 34:123‒
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© 2017
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Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Tropical Grasslands-Forrajes Tropicales (2017) Vol. 5(2):77– 84 77
Research Paper
Effects of harvesting age and spacing on plant characteristics,
chemical composition and yield of desho grass ( Pennisetum
pedicellatum Trin.) in the highlands of Ethiopia
Efectos de la edad a la cosecha y del espaciamiento en las características de
planta, composición química y rendimiento del pasto desho (Pennisetum
pedicellatum Trin.) en las tierras altas de Etiopía
GENET TILAHUN1, BIMREW ASMARE2 AND YESHAMBEL MEKURIAW2
1 South Gondar Zone Agricultural Office, Debre Tabor, Ethiopia
2 Department of Animal Production and Technology, College of Agriculture and Environmental Sciences, Bahir Dar
University, Bahir Dar, Ethiopia. www.bdu.edu/caes
Abstract
The study was conducted to evaluate effects of harvesting age and plant spacing on plant characteristics, composition
and forage yield of desho grass ( Pennisetum pedicellatum Trin.). A factorial experiment with 3 harvesting ages (75, 105
and 135 days after planting) and 3 plant spacings (10 × 50, 30 × 50 and 50 × 50 cm) with 3 replications was used. The
data collected were morphological characteristics such as leaf length, plant height, number of tillers per plant and number of leaves per plant. Chemical analysis was conducted for crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL), and dry matter yield (DMY) was quantified. Results indicated
that the only morphological characteristic significantly (P<0.05) affected by plant spacing was leaf length. However,
harvesting age significantly (P<0.01) affected morphological characteristics and DMY as well as CP and NDF (P<0.05).
Dry matter yield increased dramatically as harvesting dates were delayed but plant spacing had no significant effect on
DMY. Crude protein concentration in forage declined as harvesting dates were delayed (10.9% at 75 d vs. 9.3% at 135
d). Factors such as weed control and amount of planting material required should be the criteria used by farmers to decide inter-row spacing as, within the conditions of our study, row spacing had minimal effect on yield. As only a single harvest at each age was conducted, the yields quoted in this study are not representative of the yields provided by multiple harvests at these intervals. Further studies are needed to quantify these differences.
Keywords: Biomass, harvesting day, morphological characteristics, nutritive value, plant spacing.
Resumen
En el distrito de Farta, Etiopía, se evaluaron los efectos de la edad a cosecha y la distancia de siembra de la hierba desho ( Pennisetum pedicellatum Trin.) sobre las características morfológicas de la planta, la composición química y el rendimiento de forraje. Se utilizó un experimento factorial con 3 edades a la cosecha (75, 105 y 135 días después de la
siembra), 3 espaciamientos de plantas (10 × 50, 30 × 50 y 50 × 50 cm) y 3 repeticiones. Se evaluaron las características
morfológicas: longitud de hoja, altura de planta, número de tallos por planta y número de hojas por planta; se determinaron las concentraciones de proteína cruda (PC), fibra detergente neutra (FDN), fibra detergente ácida (FDA) y
lignina detergente ácida; y se cuantificó el rendimiento de materia seca (MS). Los resultados mostraron que la longitud
de hoja fue la única característica morfológica que fue afectada (P<0.05) por el espaciamiento de siembra de las plantas, ___________
Correspondence: B. Asmare, Department of Animal Production and
Technology, College of Agriculture and Environmental Sciences,
Bahir Dar University, P.O. Box 5501, Bahir Dar, Ethiopia.
E-mail: limasm2009@gmail.com
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
78 G. Tilahun, B. Asmare and Y. Mekuriaw
mientras que la edad a la cosecha afectó tanto las características morfológicas y el rendimiento de MS (P<0.01) como la PC y la FDN (P<0.05). El rendimiento de MS aumentó marcadamente a medida que la edad a cosecha fue mayor, mientras que el espaciamiento de las plantas no tuvo un efecto significativo sobre los rendimientos obtenidos. La concentración de PC en el forraje disminuyó a medida que el intervalo de cosecha fue mayor (10.9% a 75 días vs. 9.3%
a 135 días). Los resultados de este estudio sugieren que buenas prácticas de manejo como el control de malezas
y la cantidad adecuada de material de siembra deben ser los criterios que deben utilizar los agricultores para seleccionar el espaciamiento entre hileras de siembra, ya que en las condiciones del estudio, la distancia no tuvo efecto sobre el
rendimiento. Como se realizó una sola cosecha a cada edad, los rendimientos obtenidos en este estudio no son necesariamente representativos de los rendimientos a obtenerse por múltiples cosechas en estos intervalos. Se necesitan
más estudios para cuantificar estas diferencias.
Palabras clave: Características morfológicas, día de cosecha, espaciamiento de plantas, producción de biomasa, valor nutritivo.
Introduction
Materials and Methods
Livestock production is an integral part of the subsistence
Description of the study area
crop-livestock systems in the Ethiopian highlands, as
The agronomic study was conducted in Farta district of
livestock provide draft power for land preparation and
northwestern Ethiopia located at 660 km northwest of
threshing, plus a source of cash income and assets and
Addis Ababa (11o32’‒12o03’ N, 37o31’‒38o43’ E; 2,720
nutrition for the rural communities. In addition, livestock
masl). The topography of the district is 45% gentle slopes,
are considered as a mobile bank that can be hired, shared,
29% flat land and 26% steep slopes. In terms of land use,
inherited and contracted by rural households (Amede et
an estimated 65% of the area is cultivated and planted
al. 2005). However, the contribution of this subsector to
with annual and perennial crops, while the areas under
date has been suboptimal (CSA 2015). One of the
grazing and browsing, forests and shrubs, settlements and
important constraints causing low productivity of
wastelands account for about 10, 0.6, 8 and 17%,
livestock is low quality and insufficient supply of forage
respectively. The total area of the district is estimated to
(FAO 2010). Overgrazing is common, resulting in land
be 1,118 km2. The average minimum, maximum and
degradation and low carrying capacity. As a result, the
mean temperatures are 9.3, 22.3 and 15.8 °C, respectively.
decline in desirable plant species and nutritional value of
The rainfall pattern is uni-modal (May‒September) and
the available feed resources, particularly protein, means
mean annual rainfall is 1,445 mm (FDOA 2015).
most animals are unable to obtain their maintenance
requirements from grazing (Mengistu 1987).
Treatments and experimental design
To combat this situation, the use of indigenous forage
A factorial arrangement of treatments was employed
plants as a feed source, e.g. desho grass ( Pennisetum
using a randomized complete block design with 2 factors
pedicellatum Trin.), is recommended (Leta et al. 2013;
(plant spacing and harvesting age) with 3 replications.
Asmare 2016). Desho grass is a perennial grass from
Three plant spacings within rows (10, 30 and 50 cm) were
Chencha district in southern Ethiopia (Welle et al. 2006)
compared at 3 harvesting dates (75, 105 and 135 days). In
and is currently utilized for soil conservation practices in
all treatments inter-row spacing was 50 cm. The total
the highlands of Ethiopia (Heuzé and Hassoun 2015). It is
experimental area was 10 × 19 m (190 m2) with individual
a highly popular, drought-tolerant species, and is used
plot size of 3 m2 and spacing between plots and repli-
as one of the major feeds for ruminants (Bogdan 1977;
cations of 50 and 100 cm, respectively. The land was
FAO 2010; Asmare 2016) with high production potential
prepared thoroughly by plowing at the start of the rainy
under a multi-cut harvesting regime (MRDP 1990).
season. Planting material of desho grass was collected
However, the optimum plant spacing and intervals
from a nursery site at Farta District Office of Agriculture
between harvests are not well known. The objective of
and planted on 15 July 2015. Urea fertilizer was applied
this study was to assess the effects of harvesting age and
at the rate of 100 kg/ha at planting and ammonium
plant spacing on morphological characteristics, dry matter
phosphate (DAP) was added at 25 kg/ha 21 days after
yield and nutritive value of desho grass in the highlands
establishment according to the local recommendations
of Ethiopia.
(Leta et al. 2013).
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Yield and forage quality of desho grass 79
Methods of data collection
yijk = all dependent variables (morphological data and
chemical composition) collected
Data were recorded throughout the experimental period
µ = overall mean
(June 2015‒October 2015) on leaf length (LL), plant
Hi = the effect of ith harvesting date (75, 105 and 135 days)
height (PH), leaf number per plant (LN) and number of
Sj = the effect of jth spacing between plants (10, 30 and
tillers per plant (NT). Six plants in each plot were
50 cm)
randomly selected for recording data at each harvesting
Hi*Sj = the interaction of harvesting date and spacing
date. The total herbage on each plot at the fixed dates was
eijk = random error.
harvested leaving out border rows. From each plot, an
For correlation analyses of parameters such as
area of 2.2 m2 was used to calculate dry matter (DM)
morphological characteristics, chemical composition
yield. Harvesting was done by hand using a sickle, leaving
and yield, simple bivariate Pearson correlation was
a stubble height of 10 cm, and the harvested herbage was
employed.
weighed fresh in the field using a field balance. Random
samples of fresh forage were taken and oven-dried at
Results
60 °C for 72 h to determine DM concentration, before
calculating dry matter yield (DMY). The dried desho
Morphological characteristics and dry matter yield of
grass samples were ground to pass through a 1 mm sieve
desho grass as affected by harvesting age and plant
(Wiley mill) and stored in airtight plastic bags until
spacing
required for laboratory chemical analysis. Total ash
concentration was determined according to AOAC
Overall, there were no significant interactions between
(1990). Nitrogen was determined by the Kjeldahl method
the effects of the main treatment variables (plant spacing
(AOAC 1990) and crude protein (CP) concentration was
and harvesting age) so main effects only are presented.
calculated as N% × 6.25. The neutral detergent fiber
The effects of harvesting age and plant spacing on
(NDF), acid detergent fiber (ADF) and acid detergent
morphological characteristics and dry matter yield of
lignin (ADL) concentrations were determined according
desho grass are shown in Table 1. Mean leaf length at
to Van Soest et al. (1991).
harvesting ages of 75 and 105 days was significantly
(P<0.05) greater than at 135 days (18.1, 18.8 vs. 17.4 cm,
Methods of data analysis
respectively).
Similarly, mean length of leaves was significantly
All data were analyzed using the General Linear Model
(P<0.05) greater at the narrow spacing (10 cm) than at the
(GLM) procedure of SAS (2007) for least squares
intermediate (30 cm) and wide spacings (50 cm) (19.0 vs.
analysis of variance. Mean comparisons were done using
18.2 and 17.7 cm, respectively). Harvesting age had a
Duncan’s Multiple Range Test (DMRT) for variables
significant effect on plant height (P<0.01) with height
whose
F-values
indicated
significant
difference.
increasing progressively from 46.2 cm at 75 days
Differences were considered statistically significant at
harvesting age to 69.8 cm at 105 days and 83.1 cm at 135
P<0.01 and P<0.05. The statistical model for the analysis
days (Table 1). Plant spacing had no significant (P>0.05)
of data was: Yijk = µ + Hi + Sj + Hi*Sj + eijk
effect on plant height with a mean height overall of
where:
66.4 cm.
Table 1. Morphological characteristics and dry matter yield of desho grass as affected by harvesting age and plant spacing.
Parameter
Harvesting age (days)
Plant spacing (cm)
75
105
135
Mean
10×50
30×50
50×50
Mean
Leaf length (cm)
19.0a
18.2b
17.7b
18.3
18.1a
18.8a
17.4b
18.1
Plant height (cm)
46.2c
69.8b
83.1a
63.4
67.3
66.2
65.7
66.4
Number of tillers/plant
36.4c
93.1b
106.4a
78.6
75.3b
76.7ab
83.9a
78.6
Number of leaves/plant
249c
554b
710a
508
497
498
517
504
Dry matter yield (t/ha)
7.1c
15.7b
25.5a
16.1
16.5
16.0
15.7
16.1
Mean values within rows followed by a different letter are significantly different at P<0.05.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
80 G. Tilahun, B. Asmare and Y. Mekuriaw
Both harvesting age and plant spacing had significant
on CPY with an overall mean of 1.57 t/ha. Ash con-
effects on tiller numbers (Table 1). Mean tiller number per
centration declined significantly (P<0.01) as harvesting
plant increased from 36.4 at 75 days growth to 106.4 at
age increased with values at 75 days exceeding those at
135 days (P<0.01), while corresponding numbers for
105 and 135 days (Table 2). Progressive increases in plant
different plant spacings were 75.3 tillers/plant at 10 cm
spacing resulted in significant increases in ash
and 83.9 tillers/plant at 50 cm (P<0.05). Leaf number per
concentration (Table 2).
plant, which, in part, determines the photosynthetic
Organic matter (OM) concentration increased
capacity of the plants, was significantly (P<0.01) affected
progressively (P<0.01) as harvesting age increased and
by harvesting age, while plant spacing had no effect on
decreased progressively (P>0.05) as plant spacing
this parameter (P>0.05) (Table 1). Number of leaves per
increased (Table 2). While NDF concentration increased
plant increased from 249 leaves at 75 days to 410 leaves
significantly as harvesting age (P<0.05) and plant spacing
at 135 days.
(P<0.05) increased, ADF concentration increased
The DM yield of desho grass was significantly
significantly (P<0.01) with increase in harvesting age but
(P<0.01) affected by harvesting age but not by plant
was unaffected (P>0.05) by plant spacing (Table 2). The
spacing (P>0.05) (Table 1). Total DM harvested in-
highest ADF concentration (48.1%) was recorded in
creased progressively from 7.1 t/ha at 75 days of age to
desho grass harvested at 135 days and grown at 50 cm
25.5 t/ha at 135 days of age. Mean DM yield overall for
plant spacing.
the different plant spacings was 16.1 t/ha.
Correlation among morphological characteristics and
Chemical composition of desho grass as affected by
chemical composition of desho grass
harvesting age and plant spacing
The relationships among morphological parameters,
The chemical composition of desho grass as affected by
nutritional parameters and yield of desho grass are shown
harvesting age and plant spacing is shown in Table 2. The
in Table 3. The analysis showed that DM % and DMY
DM concentration showed minimum variation and ranged
were positively correlated (P<0.01). These parameters
from 88.2 to 89.1%. Crude protein (CP) concentration
were also positively correlated with most chemical
was significantly affected (P<0.05) by harvesting age,
parameters, e.g. CPY plus NDF, ADF, ADL and OM
declining from 10.9% at 75 days to 9.3% at 135 days.
concentrations. This indicated that, as the DM %
Crude protein yields (CPY) increased progressively and
increased, cell wall constituents also contributed to the
significantly (P<0.01) as growth period increased (0.76
increase in DMY. However, DM % and DMY were
t/ha at 75 days to 2.36 t/ha at 135 days; Table 2). By
negatively correlated (P<0.01) with CP % and total
contrast, plant spacing had no significant effect (P>0.05)
ash %.
Table 2. Chemical composition of desho grass as affected by harvesting age and plant spacing.
Parameter
Harvesting age (days)
Plant spacing (cm)
75
105
135
Mean
10×50
30×50
50×50
Mean
Dry matter (%)
88.2b
88.4b
89.0ab
88.5
89.1a
88.3b
88.2b
88.5
Ash (%)
9.16a
7.89b
7.0b
8.0
6.15c
8.15b
9.74a
8.1
Organic matter (%)
79.1c
80.6b
82.0a
80.6
83.0
80.2
78.5
80.9
Crude protein (%)
10.9a
10.2ab
9.3b
10.2
9.6
10.2
10.7
10.2
Crude protein yield (t/ha)
0.8c
1.6b
2.4a
1.57
1.5
1.6
1.6
1.6
Neutral detergent fiber (%)
45.2b
46.2b
51.7a
47.7
45.2c
47.8ab
50.1a
47.7
Acid detergent fiber (%)
33.1c
37.6b
42.6a
37.8
37.6
38.1
41.5
38.1
Acid detergent lignin (%)
17.3b
18.3b
20.7a
18.8
16.9c
18.8b
20.5a
18.7
Within parameters and treatments, means with different letters within rows are significantly different (P<0.05).
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Yield and forage quality of desho grass 81
Table 3. Correlation coefficients among morphological parameters, nutritional parameters and yields of desho grass.
DM DMY
CP
CPY
Ash
OM
NDF
ADF
ADL
LL
NT
PH
NL
DM
1
0.55** -0.43*
0.44*
-0.69** 0.81**
0.41*
-0.064
0.063
-0.02
0.31
0.44*
0.40*
DMY
1
-0.62** 0.95** -0.45*
0.50**
0.49** 0.59** 0.59** -0.42*
0.87** 0.94** 0.92**
CP
1
-0.29
0.26
-0.32
-0.26
-0.17
-0.08
0.18
-0.40*
-0.44*
-0.44*
CPY
1
-0.41*
0.44*
0.44*
0.63** 0.62** -0.43*
0.87** 0.93** 0.91**
Ash
1
-0.98** -0.41*
0.029
0.28
-0.23
-0.35
0.47*
0.44*
OM
1
0.44*
-0.40
-0.24
-0.18
0.36
0.49** 0.46*
NDF
1
0.12
-0.009
-0.27
0.03
0.47*
0.42*
ADF
1
0.6**
-0.46*
0.65** 0.58** 0.63**
ADL
1
0.62** 0.55** 0.53** 0.54**
LL
1
-0.29
-0.30
-0.30
NT
1
0.95** 0.97**
PH
1
0.97**
NL
1
Level of significance: ** = P<0.01; * = P<0.05; DM = dry matter %; DMY = dry matter yield; CP = crude protein %; CPY = crude protein yield; Ash = ash %; OM = organic matter %; NDF = neutral detergent fiber %; ADF = acid detergent fiber %; ADL = acid detergent lignin %; LL = leaf length; NT = number of tillers per plant; PH = plant height; and NL = number of leaves per plant.
Discussion
increase in tiller number, leaf formation, leaf elongation
and stem development. Similarly, Melkie (2005) reported
Plant characteristics and their relation with DM yield
that yield of Bana grass increased as harvesting stage
increased.
The absence of any significant effect of plant spacing on
The observed high number of leaves per plant at later
dry matter yield (DMY) (P>0.05) was at variance with
stages of harvesting reinforces the findings of Asmare
the findings of Melkie (2005), who demonstrated the
(2016) with the same grass species, Butt et al. (1993) and
highest DMY at narrow spacing, which he attributed to
Melkie (2005) with Bana grass and Zewdu et al. (2002)
the greater number of plants per unit area. In our study the
with Napier grass. Generally, the longer the vegetative
higher plant population at narrow plant spacing was
phase and the taller the plant, the greater the number of
counteracted to some extent by the greater number of
leaves produced (Hunter 1980), a situation reflected in our
tillers per plant produced at wider plant spacing, although
study as the number of leaves from new tillers generally
individual leaves were longer at narrow plant spacing.
increased with increase in age at harvesting. The increase
The finding that narrow plant spacing (10 and 30 cm)
in plant height with harvesting age was not unexpected.
produced longer leaves than wider spacing (50 cm)
In the same grass species, Asmare (2016) showed that
supports the results of Yasin et al. (2003), who reported
plant height increased as plant age at harvest advanced to
that narrow spacing in Napier grass increased interplant
120 days. Increments in plant height at later harvest stages
competition, causing individual plants to grow taller with
longer internodes, plus slender, thin and weak stalks
could be due to massive root development and efficient
due to poor light exposure and hence poor photosynthetic
nutrient uptake, allowing the plant to continue to increase
output. However, Melkie (2005) and Alemu et al. (2007)
in height as mentioned by Melkie (2005).
reported the opposite effect for Bana grass ( Pennisetum
The current finding that the number of tillers per plant
purpureum × Pennisetum americanum hybrid), where
increased as plant spacing increased agrees with Melkie
leaf length at relatively narrow plant spacing was shorter
(2005), who reported similar results for Bana grass. At
than at medium and wider plant spacings.
wider spacing, light can easily penetrate to the base of the
The higher dry matter yields at later stages of
plant and this may have stimulated tiller development.
harvesting were to be expected as plants were taller, had
Moreover, under wider spacing competition for nutrients
more tillers per plant and more leaves per plant. All these
is less, so individual plants can support more tillers. For
characteristics would contribute to increased photo-
Napier grass, Yasin et al. (2003) reported that, when
synthetic activity and hence higher DM production.
sufficient space is available to the individual plant, there
Ansah et al. (2010) showed that total herbage yield in
is capacity to increase the number of tillers per plant with
Napier grass increased with increase in harvesting age
the variation among the different spacings being ascribed
(60<90<120 days), which these authors attributed to the
to variable nutritional areas and access to light.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
82 G. Tilahun, B. Asmare and Y. Mekuriaw
At narrow spacing, plants reach maturity before the
Chemical composition and its relation to yield
achievement of optimal leaf area, which is important for
estimating pasture productivity. Thus, the lower tiller
Chemical analyses of forage in this study revealed that
counts at narrow plant spacing may be due to high plant
results conformed with other studies in terms of the
competition for resources, namely light, space and
effects of age at harvest on quality parameters. As would
nutrients. The increased competition for light causes
be expected, the highest CP concentration was obtained at
reduced growth and tillering capacity. Interplant com-
the earliest stage of harvesting, with values declining as
petition in grass causes rapid and exhaustive height
harvesting was delayed. This result agrees with the
increments, so that overcrowding results in neighboring
findings of Asmare (2016) for the same species.
plants producing weak tillers (Boonman 1993). There-
Similarly, Bayble et al . (2007) and Ansah et al . (2010)
fore, the competitor plants are forced to grow upright to
reported for Napier grass a decreasing trend of CP with
dominate other tillers produced on the same plant rather
increase in harvesting age (60>90>120 days). This
than expanding laterally by bearing more tillers.
phenomenon is referred to as a growth dilution effect with
Desho grass harvested at young age in this study
increase in structural carbohydrate content of forage
had excellent nutritional value, particularly high CP
materials harvested at late maturity reducing the
concentration, a limiting nutrient in tropical forages.
percentage of protein in the forage.
Even forage cut at 135 days of age had CP concentrations
Despite the reduction in CP percentage with time,
well above 7.0%, which is the level below which
crude protein yield (CPY) increased significantly as
voluntary intake of ruminants might be depressed. All of
harvesting was delayed. Similar findings have been
the forage produced would provide sufficient energy and
reported by Asmare (2016) for the same grass species and
protein to support some level of production above a
by Melkie (2005), who recorded mean CPYs at 60, 90 and
maintenance level. However, harvesting at the early
120 days of age of 0.47, 0.91 and 0.85 t/ha, respectively,
stage resulted in low DM yields at that harvest.
in Bana grass. Obviously, decisions on the optimal time
Allowing the plants to grow until 135 days of age resulted
to harvest desho grass will depend on a compromise
in much higher yields without a great reduction in
between yield and quality of forage.
quality despite some reduction in CP concentration and
However, plant spacing had no marked effect on CPY.
increase in NDF. In any pasture situation, compromises
Since CPY is the product of total DM yield and CP
between quality and yield must be made when
concentration in the plant and there were no significant
deciding at what stage to harvest or graze a crop or
effects of plant spacing on either of these parameters,
pasture.
one would not expect to record a significant outcome.
With regard to plant spacing and forage production,
Our results are at variance with those of Melkie (2005),
both narrow and wide plant spacings have implications
who found lower CPY at a spacing of 75 × 75 cm than at
for different aspects of forage production (Rao 1986) as
100 × 50 cm.
the number of plants per unit area is the primary source of
As would be expected, neutral detergent fiber (NDF),
competition. Generally, narrow plant spacing suppresses
acid detergent fiber (ADF) and acid detergent lignin
the emergence of various weeds, but additional planting
(ADL) concentrations all increased significantly (P<0.05)
material is required. When density is maintained above
as harvesting time was delayed. Increase in plant spacing
optimum, there will be greater total demand for resources
also resulted in higher NDF and ADL levels, although
that results in stress in the plants (Trenbath 1986). Wider
ADF was unaffected. While increase in stem percentage
plant spacing requires less planting material and enables
and increased lignification with maturity would account
greater tillering capacity in forage grasses but the
for the age effects, the increases with wider plant spacing
probability of weed invasion increases and may lead to
would possibly reflect larger tiller development in the
extra cost of weeding. Again compromises must be made.
wider-spaced plants. Zewdu et al. (2002) and Bayble et al .
Individual farmers may find that the optimum plant
(2007) reported that the predominant features of
density and total population differ from those of others
increasing plant density or narrow spacing were a marked
based on the resources at their disposal. Yasin et al.
reduction in leaf:stem ratio, which in turn resulted in an
(2003) indicated that the correct use of relatively
increase in cell wall and lignin concentrations in Napier
inexpensive and simple management practices such as
grass. The increasing trend of NDF concentration with
correct plant spacing, regular weeding, appropriate
increase in harvesting age agrees with Asmare (2016) for
cutting systems and application of fertilizers can help
the same grass species, where NDF concentration
increase the level of fodder production.
increased from 72.8% at 90 days to 77.7% at 150 days of
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Yield and forage quality of desho grass 83
age. Bayble et al. (2007) recorded a similar trend when
North America 1(5):923‒929. DOI: 10.5251/abjna.2010.1.
Napier grass was harvested at 60, 90 and 120 days.
AOAC (Association of Analytical Chemists). 1990. Official
Conclusions
methods of analysis. 15th Edn. AOAC Inc., Arlington, VA,
USA.
Asmare B. 2016. Evaluation of the agronomic, utilization,
This study has documented the increases in yield of desho
nutritive and feeding value of desho grass ( Pennisetum
grass as days to harvest are increased and has highlighted
pedicellatum) . Ph.D. Dissertation. Jimma University,
the reduction in quality, especially reduced CP concen-
Jimma, Ethiopia. http://hdl.handle.net/10568/77741
trations and increased NDF, ADF and ADL concen-
Bayble T; Melaku S; Prasad NK. 2007. Effects of cutting dates
trations, with advancing maturity. Farmers could use this
on nutritive value of Napier ( Pennisetum purpureum) grass
information to assist in making decisions based on the
planted sole and in association with Desmodium
relative importance of forage yield and quality in their
( Desmodium intortum) or Lablab ( Lablab purpureus).
operations. While delayed harvesting results in increased
Livestock Research for Rural Development 19, article #11.
www.lrrd.org/lrrd19/1/bayb19011.htm (accessed 11 May
DMY, this is at the expense of a reduction in quality.
2016)
However, these data do not present a complete picture as
Bogdan AV. 1977. Tropical pasture and fodder plants (grasses
the pasture harvested early would regrow and the
and legumes). Longman, London, UK.
reduction in yield we observed would be much greater
Boonman JG. 1993. East Africa’s grasses and fodders: Their
than actually would occur, where repeated cuttings would
ecology and husbandry. Kluwer Academic Publishers,
be made for the earlier ages of harvest.
Dordrecht, The Netherlands.
The absence of any differences in yield with variation
Butt NM; Gary B; Donart MG; Southward RD; Noror M. 1993.
in plant spacing indicates that farmers can make their
Effect of defoliation on plant growth of Napier grass.
decisions on what spacing to use based on other factors,
Tropical Science 33:111‒120.
CSA (Central Statistics Agency). 2015. Agricultural sampling
e.g. forage quality issues, weed control etc. Our findings
survey report on livestock and livestock characteristics
suggest that plant spacing within rows can be varied quite
(private peasant holdings). Statistical Bulletin 578, Addis
markedly without any variation in forage yield and within
Ababa, Ethiopia.
the bounds of the spacings we used, farmers can choose a
Heuzé V; Hassoun P. 2015. Nigeria grass (Pennisetum
spacing to suit their conditions. An important limitation
pedicellatum). Feedipedia, a programme by INRA, CIRAD,
of this study was that the measurements of total forage
AFZ and FAO. www.feedipedia.org/node/396 (accessed 02
yield at different harvest frequencies were not carried out.
February 2015)
This information would be needed before a farmer could
FAO (Food and Agriculture Organization of the United
use these data effectively in decision making. Moreover,
Nations). 2010. Grassland Index. A searchable catalogue of
leaf:stem ratio was not measured in this study, a good
grass and forage legumes. FAO, Rome, Italy. https://goo.gl/
indicator of forage quality. Both limitations of this study
FDOA (Farta District Office of Agriculture). 2015. Annual
could be addressed in future studies.
report, Farta, Ethiopia (unpublished).
Hunter RB. 1980. Increased leaf area (source) and yield of
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(Received for publication 26 December 2016; accepted 26 March 2017; published 31 May 2017)
© 2017
Tropical Grasslands-Forrajes Tropicales is an open-access journal published by Centro Internacional de Agricultura Tropical (CIAT). This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported license. To view a copy of this license, visit
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Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Tropical Grasslands-Forrajes Tropicales (2017) Vol. 5(2):85– 93 85
Research Paper
Weeds alter the establishment of Brachiaria brizantha cv. Marandu
Malezas afectan el establecimiento de Brachiaria brizantha cv. Marandu
SIDNEI R. DE MARCHI1, JOSÉ R. BELLÉ1, CELSO H. FOZ1, JUCILENE FERRI1 AND DAGOBERTO MARTINS2
1 Universidade Federal de Mato Grosso, Barra do Garças, MT, Brazil. www.ufmt.br
2 Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, SP, Brazil.
Abstract
The present study evaluated the effects of different periods of coexistence among the main weeds and Marandu brachiaria
grass ( Brachiaria brizantha, now Urochloa brizantha) in newly sown pasture. The experiment was conducted in a randomized block with 4 replications, with treatments being 8 coexistence periods: 0, 15, 30, 45, 60, 75, 90 and 120 days after emergence. A phytosociological assessment of the weed community was carried out at the end of the coexistence
periods, and weeds were eliminated from the appropriate treatment using herbicide. Key morphogenic parameters of the
forages were assessed at the end of the experimental period and dry matter production was determined. Results indicated
that the presence of weeds had negative impacts on the main morphogenic components, such as plant height, number of
tillers and production of leaf and stem dry matter. The presence of weeds reduced productivity in Marandu, with 15 days
competition being sufficient to reduce forage production by approximately 50%, suggesting that weed control measures
should be adopted within 15 days following emergence of seedlings of Marandu and weeds.
Keywords: Dry matter, interference, pasture renovation, weed competition.
Resumen
En un latosol localizado en Sinop, Mato Grosso, Brasil se evaluaron los efectos de la infestación de las principales malezas de la zona ( Hyptis suaveolens, Senna obtusifolia y Sida rhombifolia), en diferentes edades después de la siembra, en la producción y algunas características morfogénicas de la gramínea forrajera Brachiaria brizantha (ahora: Urochloa brizantha) cv. Marandu. Los tratamientos fueron dispuestos en un delineamiento experimental de bloques al azar con 4
repeticiones y consistieron en los períodos de convivencia: 0, 15, 30, 45, 60, 75, 90 y 120 días después de la emergencia de la gramínea. Al finalizar cada uno de estos períodos se realizó una evaluación fitosociológica de la comunidad infestante y se eliminaron las malezas utilizando un herbicida. Al término del período experimental se evaluaron los
principales parámetros morfogénicos del pasto, así como la producción de materia seca. Los resultados mostraron un
efecto negativo de las malezas en la altura de planta y el número de rebrotes, así como en la producción de materia seca
de hojas y tallos. La presencia de las malezas redujo la producción del pasto en todos los tratamientos, variando de 50%
(competencia durante los primeros 15 días) hasta 74% (120 días). Por tanto las medidas de control de las malezas deben
ser adoptadas durante las 2 primeras semanas de convivencia con el pasto Marandu.
Palabras clave: Competencia, interferencia, materia seca, renovación de pasturas.
___________
Correspondence: S.R. de Marchi, Universidade Federal de Mato
Grosso, Av. Valdon Varjão 6390, Barra do Garças CEP 78600-000,
MT, Brazil.
Email: sidneimarchi.ufmt@gmail.com
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
86 S.R. de Marchi, J.R. Bellé, C.H. Foz, J. Ferri and D. Martins
Introduction
and can reach 20,000 kg DM/ha (Benett et al. 2008). It is
considered an excellent source of good quality feed when
Historically, the livestock production model practiced by
appropriately
fertilized
and
managed.
However,
most South American ranchers has a strong extractive
nutritional value declines rapidly following flowering
aspect with little concern for protecting and renewing the
(Valle et al. 2000).
natural resources. This absence of the use of technical
All studies we found in the literature on weed control
criteria in the utilization of natural resources results in
in pastures focused on studying the effects of herbicides
accelerated degradation of pasture areas, where
on controlling unwanted plants (Silva et al. 2005; Santos
degradation is mainly characterized by loss in the
et al. 2007; Trigueiro et al. 2007). Practically no attention
productive capacity of the forage grass due to the severe
has been given to the study of interference relations
loss of soil fertility and the increase in weed infestation
between weeds and grasses, especially with regards to
(Lima and Pozzobon 2005). Renewal of the area is the
productivity and carrying capacity of the pasture.
most rational solution when a pasture becomes degraded.
This work sought to study the effects of increasing
Renewal consists basically of destroying the old
periods of weed presence on the initial development of
vegetation, correcting soil fertility and planting the
Brachiaria brizantha cv. Marandu forage.
appropriate forage species for the local conditions,
usually an exotic (introduced) species (Macedo 2009).
Materials and Methods
The process of renovating the degraded pasture, however,
is ineffective in removing the seeds left by weeds, so weed
The experimental phase of this work was conducted in a
and pasture seeds germinate together, which initiates a
pasture renewal area in the municipality of Sinop, Mato
new degradation cycle (Martins et al. 2007).
Grosso, Brazil, (11º11’29’’ S, 55º15’13’’ W), where,
Brachiaria grass ( Brachiaria brizantha, now Urochloa
according to the Köppen (1948) classification, the climate
brizantha) is one of the most cultivated forages in the
is of type Aw. Rainfall data and average, minimum and
warm regions of South America and supports a large
maximum temperatures recorded during the experimental
portion of the cattle herd. It has high forage yield,
period are shown in Figure 1. The average annual
persistence, good capacity for regrowth and relative
temperature is 27 ºC, varying between 17 and 40 ºC.
tolerance to attacks from spittlebugs such as Deois sp. The
Average annual precipitation is 1,500 mm, varying from
average annual productivity is 4,000‒8,000 kg DM/ha
1,200 to 1,800 mm.
35
600
30
500
25
400
C)
)
o (
m
e 20
r
m(
u
t
l
300
l
a
a
r
f
e 15
n
p
ia
m
R
e
200
T 10
100
5
0
0
Oct/10
Nov/10
Dec/10
Jan/11
Feb/11
Mar/11
Rainfall
T average
T minimum
T maximum
Figure 1. Average monthly rainfall and temperature during the experimental period.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Weeds affect establishment of Marandu 87
Representative soil samples (latosol) were collected
DeR = (De/Dt) x 100 (%), where: De is the density of each
and sent for laboratory analysis, which revealed the
weed species and Dt is the total weed density; DoR refers
following chemical characteristics: pH (H2O): 3.9; soil
to the relative dominance of each species and is estimated
organic matter: 18.45 g/dm3; P: 0.04 g/dm3 (Mehlich-1);
by the formula: DoR = (DMe/DMt) x 100 (%), where:
K+: 0.04 cmmol/dm3; Ca2+: 0.09 cmmol/dm3; Mg2+: 0.03
DMe is the dry matter of each weed species and DMt is
cmmol/dm3; Al3+: 0.3 cmmol/dm3 (KCl 1 mol/L); base
the total dry matter accumulated by the weed community;
saturation: 0.16 cmmol/dm3; and effective CEC of 21%.
and RF refers to the relative frequency of each species and
Physical analysis indicated 866 g sand/kg, 39 g silt/kg and
is estimated by the formula: RF = (FAe/FAt) x 100 (%),
91 g clay/kg, characterizing the soil as having a sandy
where: FAe is the absolute frequency of each species
texture. Based on these results, calcium lime was applied
calculated by the expression: FAe = (NAe/NAt) x 100,
in the third week of September 2010 at rates of 2,000
where: NAe indicates the number of samples for a
kg/ha, while 62.5 kg P/ha (as single superphosphate), 25
determined species; NAt is the total number of samples
kg N/ha (as urea) and 37.5 kg K/ha (as KCl) were
obtained; and FAt is the sum of the absolute frequencies
broadcast on all areas in the first week of November 2010.
of all species of the weed community (Mueller-Dombois
Existing forage was removed from the experimental
and Ellenberg 1974).
area by herbicide application (glyphosate at 2.5 L/ha)
All weeds were removed from the respective plots at
followed by mechanical tillage of soil before the study
the end of each period of coexistence by spraying with
commenced in November 2010. The area was fenced to
exclude animals for the duration of the study. Seed of cv.
herbicide, and thereafter any emerging weeds were
Marandu with 70% maximum germination was broadcast
removed by applying 1.5 L/ha of herbicide formulated
on the area at a rate of 6.0 kg/ha. Seedling emergence
with 40 g acid equivalent/L of aminopyralid and 320 g
commenced in 7 days and complete emergence occurred
acid equivalent/L of 2,4-D post-emergence.
by 10 days. The experimental area was divided into 32
The grass was evaluated only at the end of the
plots, each of 16 m2 (4.0 x 4.0 m) with the central 9.0 m2
experimental period, corresponding with 120 days after
of each plot used as the sampling area. The experimental
emergence of the seedlings, when the first grass
design was a complete randomized block, with 8
inflorescences emerged. At this time plant height, number
treatments representing different periods of coexistence
of tillers per plant and number of plants per square meter
between forage and weed species (0, 15, 30, 45, 60, 75,
were measured. Forage samples were collected by cutting
90 and 120 days after emergence) and 4 replications.
the plants to 10 cm from the ground within the area
Assessments of the pasture communities for each
enclosed by the 1.0 m2 metal square, cast randomly in the
treatment were performed at the end of the coexistence
sampling area of the experimental unit.
period for that treatment with the aid of a 1.0 m2 metal
The samples were sent to the laboratory and sorted into
square randomly cast within the sampling area of each
green leaves, green stems and dead matter. The green
plot. All weed species within the metal square were
inflorescences present were considered as part of the
separately identified, counted, cut at stem base and taken
stem. The various fractions were duly packed in properly
to the laboratory, where they were placed in properly
labeled and perforated paper bags and dried in a forced-
labeled and perforated paper bags to be dried in a forced-
air circulation oven at 60‒63 ºC for 72 hours. Dry matter
air oven at 60‒63 ºC for 72 hours. After this procedure,
(DM) yields for the different fractions [green leaf dry
the dry weight of the stems and leaves of each collected
matter (GLDM), green stem dry matter (GSDM), dead
species was determined by using a 0.01 g precision
material dry matter (DMDM) and total dry matter (TDM)]
balance.
were calculated. Dry matter yields for the different
The relative importance (RI) of the weeds was
treatments were compared with those for the 0 days
calculated by the formula:
treatment (control, = weed-free throughout) to determine
RI = (IVIe/IVIt) x 100 (%), where: IVIe refers to the
the suppression in yield by exposure to weeds for the
importance index of a determined species; and IVIt
various times according to the formula:
signifies the sum of the importance indices of all
ROF = [(MST – MSPC)/MST] x 100, where: ROF is
components of the community. The importance index of
the reduction in forage offering in percent; MST is the
each species is estimated by the formula:
total DM produced by the forage species that remained
IVI = DeR + DoR + RF, where: DeR refers to the rela-
weed-free for 120 days; and MSPC is the DM produced
tive density of each species, estimated by the formula:
by treatments with differing periods of weed infestation.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
88 S.R. de Marchi, J.R. Bellé, C.H. Foz, J. Ferri and D. Martins
The values obtained were submitted to analysis of
Results
variance by the F-test and the effects of the treatments
were compared by the Scott-Knott test at 5% probability.
Only 3 weed species emerged during the experimental
The average values of total DM produced by Marandu and
period: Hyptis suaveolens (L.) Poit. (Lamiaceae) (local
observed at 120 days were also adjusted according to the
name: cheirosa), Senna obtusifolia (L.) H.S. Irwin &
Barneby (Leguminosae – Caesalpinioideae) (local name:
Boltzmann model for better understanding of the effects
fedegoso) and Sida rhombifolia L. (Malvaceae) (local
of coexistence, as used by Kuva et al. (2001). This model
name: guanxuma). Senna obtusifolia accumulated the
conforms to the following equation:
greatest amount of DM up to 45 days after emergence
(DAE), but was the only species that showed a reduction
(A
Y =
1 − A2)
+ A
in DM accumulation at 120 DAE (Figure 2). Over the full
1 + e(x− x
2
0)/dx
120 days, H. suaveolens showed the highest DM accu-
mulation with rapid growth from 45 to 120 DAE; DM
where: Y is the estimated DM yield of the forage in g/m2;
accumulation was almost 2.5 times that of S. obtusifolia
x is the upper limit of the coexistence period or control
(Figure 2).
considered; A1 is the estimated yield obtained in the
Sida rhombifolia produced little growth up to 90 DAE,
plots maintained clean throughout the cycle; A2 is the
when compared with the other 2 species, but
minimum estimated production obtained in the units
accumulation of DM increased considerably from 90
maintained with weeds throughout the cycle; xo is the
DAE. At 120 DAE total DM produced by the weeds was
upper limit of the control or coexistence period
288 g/m2 (Figure 2).
corresponding to the intermediate value between
The relative importance, obtained from density,
maximum and minimum production; and dx is the
dominance and frequency of each of the 3 species, was
parameter that indicates the velocity loss or production
relatively equal throughout the experimental period
gain (tg α at point xo).
(Figure 3).
180
150
²)
Senna obtusifolia
Hyptis suaveolens
Sida rhombifolia
120
(g/m
re
90
attm
y
60
Dr
30
0
15
30
45
60
75
90
120
Coexistence period (days)
Figure 2. Dry matter accumulated by the weeds in their coexistence periods.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Weeds affect establishment of Marandu 89
100
)
% 80
RI (
Senna obtusifolia
Hyptis suaveolens
Sida rhombifolia
-
60
tance
or
p 40
im
20
lative
Re
0
15
30
45
60
75
90
120
Coexistence period (days)
Figure 3. Relative importance (%) of the weed species in their respective coexistence periods.
The height of Marandu was significantly altered by
of Marandu plants did not differ between treatments
coexistence with the weeds; height of the control forage
(P>0.05) with a mean of 37.3 plants/m2 at 120 days post
at 120 days was 62 cm compared with a mean of 38 cm
emergence (Table 1). The production of green leaf, stem
for the remaining treatments (Table 1).
and total forage dry matter was significantly reduced by
Similarly, exposure to weeds for periods of >15 days
the presence of weeds in the sward, even for as little as 15
significantly reduced the number of tillers per plant (4.2
days (P<0.05; Table 2). After 120 days of growth,
and 3.8 for 0 and 15 days, respectively, vs. a mean of 2.7
total DM production was suppressed by 50%, when
for the remaining treatments; P<0.05) (Table 1). Density
weeds remained in the pasture for as little as 15 days
Table 1. Effects of duration of weed competition in a Marandu pasture on height, number of tillers per plant and density of Marandu plants at 120 days after emergence.
Days of coexistence
Height
Number of tillers
Density
(cm)
(No./plant)
(No. of plants/m2)
0
61.7a1
4.2a
40.4
15
42.7b
3.8a
30.3
30
40.5b
3.0b
42.8
45
32.5b
3.0b
32.5
60
30.2b
2.7b
40.5
75
49.0b
2.5b
32.5
90
38.0b
2.3b
38.0
120
32.5b
3.0b
41.5
F Days
3.84*
4.80*
0.86NS
F Block
0.19NS
4.08*
0.14NS
C.V. (%)
26.11
19.23
27.97
1Means followed by the same letter within columns do not differ by the Scott-Knott test at 5% probability.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
90 S.R. de Marchi, J.R. Bellé, C.H. Foz, J. Ferri and D. Martins
Table 2. Effects of duration of weed competition on the production (kg/ha) of green leaf dry matter (GLDM), green stem dry matter (GSDM), dead material dry matter (DMDM) and total dry matter (TDM) of Marandu and reduction in forage offering (ROF) at 120
days after emergence.
Days of
GLDM
GSDM
DMDM
TDM
ROF1 (%)
coexistence
0
1,543a2
1,632a
256
3,431a
-
15
790b
710b
210
1,710b
50.2
30
610b
790b
165
1,565b
54.4
45
470b
480b
136
1,086b
68.3
60
460b
410b
193
1,063b
69.0
75
420b
490b
100
1,010b
70.6
90
530b
340b
111
981b
71.4
120
430b
350b
110
890b
74.1
F Days
5.35*
5.96*
1.41NS
6.01*
-
F Block
0.32NS
0.83NS
0.84NS
0.31*
-
C.V. (%)
49.82
54.02
58.68
47.06
-
1Reduction in forage offering relative to the control (0 days).
2Means followed by the same letter within columns do not statistically differ by the Scott-Knott test at 5% probability.
after emergence. This reduction in yield had increased to
The relationship between total DM yield and number
74% when weeds remained in the pasture for the full 120
of days that weeds remained in the pasture is presented in
days (Table 2), but there were no significant differences
Figure 4. Accordingly the suppressant effects of weeds on
between yields for the differing times that weeds
pasture growth had been expressed by 45 days after
remained in the pasture.
emergence.
3000
3,000
Y = [2,942.3/(1 + e(x-11.0738)/6))] + 890.0
)
Y = ((2942,3) / (1 + e(x-11,0738) / 6)) + 890,0*
-1
R2 = 0.8129
a) ha
R2 = 0,8129
h g (k
2000
2,000
(kg/ ld
r ie
te yats
m s
a
y m
1000
1,000
Dr ry
D
0
0
15
30
45
60
75
90
105
120
Coexi
Coe sten
xistence
ce p
per
e i
r od
iod (d
ay)
(days)
Figure 4. Relationship between forage DM yield of Marandu and duration of weed growth in the pasture.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Weeds affect establishment of Marandu 91
Discussion
results with most rapid growth of this species between 75
and 120 DAE. It is significant that DM yields of this
This study has shown that weeds can provide severe
species at 120 days were equal to those of Marandu in the
competition for freshly sown stands of Marandu, which
unweeded plots. Sida rhombifolia, despite the low DM
reduces DM production of the grass, even if weeds are
accumulation during virtually the entire period, began
present only for a short period initially, e.g. as little as 15
to show greater vegetative growth only after 90 DAE,
days. It could be concluded that this is due to competition
which is in agreement with findings of Bianco et al.
for available resources, especially nutrients, sunlight and
(2014). When analyzing growth and mineral nutrition of
moisture.
S. rhombifolia, these authors found that the species
Interference of the weeds was most evident on the
actually has slow vegetative growth up to 80 DAE, with
height and number of tillers generated by Marandu plants.
peak DM accumulation occurring after 140 DAE.
Nepomuceno et al. (2007) reported that plant height is not
However, the authors also found that, although initial
an adequate characteristic to evaluate the competition
growth is slow, this species has a high capacity for
between species, since plants subjected to competition
absorbing nutrients from about 35 DAE and has a
prioritize height growth in search of light rather than the
comparatively higher capacity to absorb nutrients than
accumulation of total DM. Vilela (2011) commented that
other weeds. It is important to note that S. obtusifolia and
tillering is a predominant feature in most grasses, and in
H. suaveolens are annuals and S. rhombifolia is a
the case of a pasture, the success of its production is
perennial species. Annual species grow more quickly than
related to good tillering and the consequent occupation of
perennials and this was probably the main factor
spaces between plants, thereby complicating the
suppressing growth of Marandu.
establishment of weed species. In this study the opposite
The different patterns of DM accumulation of the 3
was observed, i.e. the weeds dominated the spaces and
weed species help to explain the similarity of the relative
adversely affected the emergence of tillers in the forage,
importance obtained for the various coexistence periods
even when present for only 15 days. In addition grass
used in this study. This behavior may be correlated with
plants subjected to competition from weed plants for only
competitiveness and the consequent coexistence of the 3
15 days showed lower vertical growth than those free of
weed species in the area. In other words, the weed species
weed competition and failed to compensate when weeds
complement one another, with S. obtusifolia having
were removed.
greater competitive ability in the early growth stages,
Both S. obtusifolia and H. suaveolens are annual
while H. suaveolens and S. rhombifolia are able to grow
weeds and grow rapidly early in life, growing much more
slowly during this period, being more prominent as Senna
rapidly than Marandu and the perennial S. rhombifolia.
matures (Gravena et al. 2002).
This may explain why the main suppressant effect of
With this complementary growth, there was always at
weeds on Marandu growth happened in the first 15 days
least one weed species exerting competitive pressure on
following emergence. These weeds are native to the
Marandu, resulting in similar suppression of grass growth
American continent with wide distribution in South
regardless of when weeds were removed. It must be
America, especially in Brazil, and often infest areas of
remembered that the annual weeds are more adapted to
annual crops, perennials and pastures (Fleck et al. 2003;
the environmental conditions, have characteristics that
Souza et al. 2011). Besides the competition for
make better use of the light, and are more efficient in the
environmental resources such as water, light and
use of nutrients, since they are native in the region, while
nutrients, they can also be toxic to animals if ingested
the majority of forage grasses are exotic in South America
during grazing (Pellegrini et al. 2007; Braga et al. 2012).
(Peron and Evangelista 2004; Benett et al. 2008). Most of
We found that S. obtusifolia grew most rapidly
them are also perennials with slow growth initially.
between 21 and 91 DAE, in agreement with the findings
It is noteworthy that the main broadleaf weed control
of Erasmo et al. (1997), after which growth rate decreased
method in grazing areas is the application of specific
significantly. Those authors suggested that the reduction
selective herbicides. This represents a significant
in growth was due to the natural senescence process of the
operating expense. Our study provides an indication of
species, with resources at that time being directed to
the possible reduction in pasture growth as a result of
reproduction. Studies performed by Gravena et al. (2002)
weed infestation, which may aid a farmer in making a
demonstrated that H. suaveolens accumulated only 31%
decision to spray weeds or to let them grow. It seems that,
of total DM up to 45 DAE, with most rapid growth
if the weeds are not treated early after emergence, it is not
between 60 and 140 DAE. Our findings support these
worth treating them in terms of the effects on pasture
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
92 S.R. de Marchi, J.R. Bellé, C.H. Foz, J. Ferri and D. Martins
growth in that season, as they will still have a depressant
Planta Daninha 20:189‒196. DOI: 10.1590/S0100-
effect on pasture growth, even if removed. There is a
small window of opportunity to take action. The decision
Köppen W. 1948. Climatología. Gráfica Panamericana, Buenos
then becomes one of preventing seed set to reduce the soil
Aires, Argentina. https://goo.gl/vqr3vV
seed bank of the weeds for subsequent seasons. Our
Kuva MA; Gravena R; Pitelli RA; Christoffoleti PJ; Alves
PLCA. 2001. Períodos de interferência das plantas daninhas
results show that the reduced growth of Marandu from
na cultura da cana-de-açúcar. II – Capim-braquiária
weed competition was a function not of fewer grass plants
( Brachiaria decumbens). Planta Daninha 19:323‒330. DOI:
but reduced growth of the same number of plants, through
10.1590/S0100-83582001000300003
reduced numbers of tillers and reduced vertical growth.
Lima D; Pozzobon J. 2005. Amazônia socioambiental.
We are not aware of similar findings being reported in the
Sustentabilidade ecológica e diversidade social. Estudos
scientific literature.
Avançados 19:45‒76. DOI: 10.1590/S0103-40142005000
We consider that the regression equation obtained in
this study should be of assistance to all professionals
Macedo MCM. 2009. Integração lavoura e pecuária: O estado
involved in the livestock production chain, especially the
da arte e inovações tecnológicas. Revista Brasileira de
meat production chain, in which the productivity of a
Zootecnia 38:133‒146. DOI: 10.1590/S1516-3598200900
forage area is heavily dependent on the presence or
absence of weeds. It should be used as a component when
Martins D; Triguero LRC; Domingos VD; Martins CC; Marchi
making decisions about weed control measures to ensure
SR; Costa NV. 2007. Seletividade de herbicidas aplicados
that the decision is soundly based economically.
em pós-emergência sobre capim-braquiária. Revista
Brasileira de Zootecnia 36:1969‒1974. DOI:
However, delaying a decision to treat weeds could have
long-term consequences, especially in terms of additional
Mueller-Dombois D; Ellenberg H. 1974. Aims and methods of
seed added to the soil seed bank. As this study lasted for
vegetation ecology. Willey & Sons Inc., New York, USA.
only 120 days, it is difficult to forecast the productivity of
Nepomuceno M; Alves PLCA; Dias TCS; Pavani MCMD.
the pasture over subsequent years. Longer-term studies
2007. Períodos de interferência das plantas daninhas na
are needed to determine how the suppression of growth of
cultura da soja nos sistemas de semeadura direta e
the grass observed here is reflected over the complete life
convencional. Planta Daninha 25:43‒50. DOI: 10.1590/
of the pasture.
Pellegrini LG; Nabinger C; Carvalho PCF; Neumann M. 2007.
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© 2017
Tropical Grasslands-Forrajes Tropicales is an open-access journal published by Centro Internacional de Agricultura Tropical (CIAT). This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported license. To view a copy of this license, visit
http://creativecommons.org/licenses/by-nc-sa/3.0/
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Tropical Grasslands-Forrajes Tropicales (2017) Vol. 5(2):94– 99 94
Short Communication
A simple method for determining maize silage density on farms
Un método sencillo para determinar la densidad en ensilaje de maíz a nivel
de finca
ANA MARIA KRÜGER, CLÓVES C. JOBIM, IGOR Q. DE CARVALHO AND JULIENNE G. MORO
Departamento de Zootecnia, Universidade Estadual de Maringá, Maringá, PR, Brazil. www.dzo.uem.br
Abstract
Several methodologies have been tested to evaluate silage density, with direct methods most popular, whereas indirect
methods that can be used under field conditions are still in development and improvement stages. This study aimed to
establish relationships between estimates of maize silage density determined using a direct and an indirect method, in an endeavor to provide an alternative to direct measurement for use in the field. Measurements were performed on maize
silage in 14 silos. The direct method involved the use of a metal cylinder with a saw-tooth cutting edge attached to a
chainsaw to extract a core of silage. Density of the silage was determined taking into consideration the cylinder volume
and dry matter weight of silage removed at 5 points on the silage face. With the indirect method, a digital penetrometer
was used to estimate silage density by measuring the penetration resistance at 2 points adjacent to the spots where the
silage cores were taken, i.e. 10 readings per silo. Values of penetration resistance (measured in MPa) were correlated
with the values of silage mass (kg/m3) obtained by direct measurement through polynomial regression analysis. A positive quadratic relationship was observed between penetration resistance and silage density for both natural matter
and dry matter (R² = 0.57 and R² = 0.80, respectively), showing that the penetrometer was a reasonably reliable and
simple indirect method to determine the density of dry matter in maize silage. Further testing of the machine on other
silos is needed to verify these results.
Keywords: Ensiled matter, penetrometer, resistance, silos evaluation.
Resumen
Para determinar la densidad de ensilado, los métodos más usados son los directos mientras métodos indirectos, que se
puedan usar a nivel de finca, están aún siendo desarrollados y mejorados. El objetivo de este estudio fue determinar la
correlación entre las densidades de ensilado de maíz determinadas con un método directo, y las determinadas con un
método indirecto. Las mediciones se hicieron en 14 silos de maíz de fincas lecheras en 5 municipios del estado de Paraná, Brasil. El método directo consistió en el uso de un cilindro metálico con un filo cortante de dientes serrados unido a una motosierra para extraer una muestra del ensilado; la densidad se determinó con base en el volumen del cilindro y el
promedio del peso de las muestras extraídas en 5 puntos. El método indirecto consistió en el uso de un penetrómetro
digital para medir la resistencia a la penetración en 2 puntos adyacentes a los sitios donde se tomaron las muestras del
método directo (10 lecturas por silo). Los datos se sometieron a un análisis de regresión polinomial que mostró una relación cuadrática positiva entre la resistencia a la penetración (medida en MPa) y la densidad del ensilaje con base en los valores de la masa del ensilado (kg/m3) tanto para la materia natural como la materia seca (R² = 0.57 y R² = 0.80,
respectivamente). Se concluye que el penetrómetro fue un método indirecto razonablemente confiable y sencillo para
determinar la densidad de la materia seca en ensilado de maíz. Para verificar estos resultados se requieren pruebas adicionales con este equipo en otros silos.
.
Palabras clave: Evaluación de silos, materia ensilada, penetrómetro, resistencia.
___________
Correspondence: A.M. Krüger, Departamento de Zootecnia, Univer-
sidade Estadual de Maringá, Maringá CEP 87020-900, PR, Brazil.
E-mail: anamkruger@yahoo.com.br
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Determining silage density on farms 95
Introduction
Materials and Methods
Greater compaction of ensiled material provides greater
Specific mass measurements were made by a direct
specific mass (SM) by expelling air and providing
method in 14 bunker silos (treatments), employing
anaerobic conditions for fermentation. This allows better
methodologies described by Holmes and Muck (1999)
conservation of soluble sugars, minor alteration of
and D’amours and Savoie (2005), in maize silages on
structural carbohydrates and reduced proteolysis in the
dairy farms in Paraná State, Brazil, specifically in the
resulting silage, aspects which increase acceptability and
Castro, Carambeí, Arapoti, Piraí do Sul and Ponta Grossa
consumption by livestock (Velho et al. 2007).
municipalities.
Direct methods are used to evaluate SM of silages,
A metal cylinder, 20 cm length and 10 cm diameter,
with a serrated cutting edge and attached to a chainsaw,
mostly the determination of herbage mass for a known
was used, as described by Craig and Roth (2005) (Figure
volume of silage, with values being expressed in kg of
1). The cylinder was screwed into the silage panel
natural or dry matter per cubic meter. However, these
mechanically through the rotation exerted by the
methods involve measuring the volume of the sample,
chainsaw. When the sample was withdrawn from the
taking it to a suitable facility and drying it for at least 24
storage panel of the silo, the depth was measured with a
hours in an oven. More rapid, indirect methods, which
rule to calculate the volume of the withdrawn sample.
however require sophisticated equipment, aim to facilitate
From the cylinder volume and the mass [both natural
the collection of such data under field conditions, such as:
matter (NM) and dry matter (DM)] of the withdrawn
radiometric sensors that present a source and a receptor
sample, the SM of the silage in the silo was calculated.
for gamma waves, a method based on microwave
Whereas NM was the mass of the fresh silage, DM was
resonance; and the georadar system, also used to estimate
determined conventionally (weighing after drying NM at
SM of soils (Jobim et al. 2007).
105 °C for 8 h in a forced-air oven).
However, these indirect methods are still in
Silage samples were withdrawn at 5 points (taken as
development and improvement stages and rely on strict
replications) in the silo panel, 3 locations at the top and 2
calibration to produce reliable data. Among the various
at the bottom, forming a ‘W’ like figure. Before the
invasive tools to determine SM of silages, the
sampling procedure commenced, a slice of silage had
penetrometer has specific advantages over other
been removed manually from each silo panel in order to
techniques because it requires a simple calibration
remove any loose silage from the silage ‘face’, so that the
procedure and can provide reliable data. Sun et al. (2010)
samples were collected from ‘intact’ (undisturbed) silage.
suggested that this technique, when properly applied, has
To estimate SM through the indirect method, a digital
the potential to provide good information about silage
penetrometer (DLG, model PNT-2000-M), which follows
storage conditions. In an on-station study under controlled
the ASAE S313.3 rule that defines penetration resistance
conditions, Silva et al. (2011) correlated resistance values
as the pressure over the area of a cone with a solid angle
provided by maize silage to penetration by a penetrometer
of 30°, was used. This equipment is used to determine the
penetration resistance in soil compaction studies
with SM values obtained by sampling with the use of a
(Figueiredo et al. 2011; Storck et al. 2016). Penetration
metal cylinder of known volume. Estimates of SM they
resistance was measured at the same time and using the
obtained with this indirect method compared favorably
same orientation as in the direct determination with the
with values obtained with direct measurement, causing
metal cylinder, with 2 measurements of resistance at each
them to conclude that the penetrometer could provide
silo panel point, thus giving 10 measurements in each silo.
reliable estimates under field conditions both quickly and
Penetration resistance was measured at points adjacent to
at low cost.
the spots where silage samples were taken for the direct
The objective of our study was to measure the SM of
measurements, at a distance of approximately 35 cm from
maize silage on farms by a direct method (core sampling
those.
in the silo panel) and an indirect measurement method
For resistance measurements, the penetrometer metal
(using a penetrometer), and to establish correlations
cone was manually pushed into the silage panel
between the estimates obtained, with the aim of
horizontally at a constant speed of approximately 2 cm/s
establishing the penetrometer as a reliable tool for
up to the end of the cone length, a mandatory procedure
estimating the degree of compaction of stored forage in
according to the instruction manual for the device (Figure
the field.
2). Penetration depth into the silo panel was 0.9 m.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
96 A.M. Krüger, C.C. Jobim, I.Q. de Carvalho and J.G. Moro
direct method (in Table 1: observed SMNM and observed
SMDM). Data were not statistically analyzed, considering
that there was no replication (silo), since the silos were
evaluated on different farms and factors other than the
type of assessed silo and silage (maize) may present
different characteristics. Therefore, the values obtained
for the SMNM and SMDM were descriptively analyzed.
Figure 1. Cylinder and chainsaw in use. Source: Personal file.
Penetrometer resistance values (in megapascal, MPa)
were correlated with the SM values (kg/m³) obtained with
use of the cylinder coupled to the chainsaw by a
polynomial regression study. The regression equations
obtained were used to calculate the values of SM for
natural matter (SMNM) and dry matter (SMDM) in each
silo (in Table 1: estimated SMNM and estimated SMDM)
and these were compared with the values obtained by the
Figure 2. Penetrometer in use. Source: Personal file.
Table 1. Dry matter concentration, resistance by ensiled mass to penetration of the metal cone (± SD), observed and estimated specific mass (natural matter and dry matter basis) (± SD) in 14 farm silos.
Silo
DM1
Resistance
SMNM (kg NM/m3)
SMDM (kg DM/m3)
(g/kg)
(MPa)
Observed
Estimated
Observed
Estimated
1
327
2.20 + 0.50
839 + 80.5
767 + 45.3
274 + 26.3
260 + 11.6
2
350
1.92 + 0.35
748 + 48.8
837 + 14.9
262 + 17.1
282 + 4.8
3
292
0.24 + 0.05
469 + 90.8
571 + 17.2
137 + 26.5
146 + 7.5
4
277
0.54 + 0.10
751 + 108.7
704 + 25.7
208 + 30.1
204 + 11.6
5
294
1.07 + 0.40
876 + 49.5
850 + 47.9
258 + 14.6
271 + 24.3
6
274
1.00 + 0.14
904 + 73.0
837 + 22.1
247 + 20.0
265 + 10.7
7
336
0.99 + 0.35
787 + 62.7
836 + 49.1
265 + 21.1
264 + 24.0
8
287
0.68 + 0.22
787 + 87.4
755 + 48.4
226 + 25.1
227 + 22.1
9
279
0.74 + 0.25
801 + 22.9
773 + 50.8
223 + 6.4
235 + 23.5
10
325
1.15 + 0.29
854 + 126.2
861 + 39.2
277 + 41.0
277 + 19.3
11
391
1.06 + 0.14
710 + 103.2
847 + 23.1
277 + 40.3
270 + 11.1
12
345
0.85 + 0.37
867 + 67.4
803 + 73.7
299 + 23.2
248 + 34.1
13
278
0.48 + 0.24
776 + 59.8
684 + 62.6
216 + 16.6
195 + 28.0
14
270
0.53 + 0.18
660 + 50.6
702 + 47.2
178 + 13.6
203 + 21.2
Mean
309
0.96 + 0.58
773 + 128.5
773 + 71.0
239 + 48.4
239 + 34.3
1DM – dry matter; NM ‒natural matter; Resistance – resistance to penetration of the metal cone; SMNM – specific mass of natural matter; SMDM – specific mass of dry matter.
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Determining silage density on farms 97
Results
Discussion
The average DM concentration found in the silages
The values observed for DM concentration of the silages
evaluated was 309 g DM/kg, ranging from 270 to 391 g
evaluated are consistent with the recommendation of
DM/kg (Table 1). Density of silage as determined by the
Nussio et al. (2001) that the optimal DM concentration of
direct method (‘observed’) ranged from 469 to 904 kg/m3
maize plants at ensiling should be 300‒350 g DM/kg.
(mean 773 ± 129 kg/m3) for NM and from 137 to 299
According to these authors, DM concentrations below
kg/m3 (mean 239 ± 48.4 kg/m3) for DM. The density
300 g DM/kg are associated with lower DM yield, losses
measurements were compared with the range in
by leaching and low silage quality, factors that may lead
penetration resistance in the silos, which varied from 0.24
to reduced intake by animals. The quality of silages was
to 2.20 MPa (mean 0.96 ± 0.58 MPa). The results for this
evidenced by parameters such as neutral detergent fiber,
comparison are shown in Figures 3 and 4.
starch content and pH, which presented mean values of
46.35 ± 4.8 %, 33.28 ± 4.62 % and 3.81 ± 0.07, respective-
ly (A.M. Krüger unpublished data).
The values obtained using the direct method indicated
that there was considerable variation in how well the
material was compacted in the silos, which can be related
to the method of compaction used, the stage of growth of
the forage when ensiled, the moisture content of the
forage at ensiling, etc. According to Jobim et al. (2007),
although there is no optimal value for silage density,
values in the range of 550‒850 kg NM/m³ are most
suitable, and these are obtained only under favorable
conditions. Typically, appropriate compression for
desirable fermentative characteristics and minimal losses
in maize silage is obtained with minimum SMDM around
225 kg DM/m³. The majority of the silages sampled were
above this minimum level. One might expect that the
nutritional value and acceptability of the silage to
Figure 3. Relationship between SMNM (specific mass based
on natural matter), expressed in kg/m³ and resistance to
livestock would also vary markedly.
penetrometer metallic cone, expressed in MPa.
The penetration resistance observed when employing
the indirect method indicates that, while there was marked
variation in density of the silage as measured directly,
there was much greater variation in resistance as
measured by the penetrometer. If one assumes that the
density measurements were accurate, one might question
the accuracy of the penetrometer readings for the same
silages.
In an experiment in which 18 penetrometer measures
were performed in one silage sample kept under
controlled conditions in an experimental station, Silva
et al. (2011) found a mean penetrometer resistance of
1.09 ± 0.23 MPa and specific mass observed based on dry
matter of 170 ± 36.5 kg DM/m³. As in the present study,
resistance values obtained were compared with direct
measurements as well.
The results obtained for SM (Table 1) observed (direct
method) and estimated (indirect method), both for NM
Figure 4. Relationship between SMDM (specific mass based
and DM, are consistent with those typically observed in
on dry matter), expressed in kg/m³ and resistance to
farm silos and the values found by the indirect method
penetrometer metallic cone, expressed in MPa.
presented a smaller range of variation when compared
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
98 A.M. Krüger, C.C. Jobim, I.Q. de Carvalho and J.G. Moro
with the direct method, because regression equations
silages with SMDM above 260 kg DM/m3 had DM % in
determine the middle pathway and reduce the effect of
the range 325‒391 g DM/kg. All silages with penetro-
outlying values. There was a positive relationship
meter readings below 0.75 MPa had DM % below 300 g
between the SM of silage and penetration resistance to the
DM/kg and SMDM below 230 kg DM/m3. The relation-
metal cone (Figures 3 and 4). This was a curvilinear
ship between DM concentration in silage and reliability
relationship with silage SM increasing as the resistance to
of the machine needs to be investigated further to confirm
the cone penetration increased to a peak of about 900 kg
these findings.
NM/m3 or 300 kg DM/m3.
Silva et al. (2011) observed a positive linear
Acknowledgments
relationship between the SM of maize silage and
penetration resistance to the metal cone in 2 experiments.
The authors thank CNPq (National Council for Research
However, in 1 of the experiments, the adjusted linear
and Technological Development) for the financial
equation had a low coefficient of determination,
support.
explaining only 33% of the observed variation. This low
coefficient was attributed to surface conformations of
References
silos used in the second experiment, since they provided
lower compression of the ensiled material, and altered the
Craig PH; Roth G. 2005. Penn State University bunker silo
density study summary report 2004–2005. Department of
physical correlation of mass and volume, which may have
Agriculture, and Pennsylvania Counties Cooperating, Penn
influenced the relationship between SM of silage and
State University, Dauphin, PA, USA. p. 1‒9. https://goo.gl/
penetration resistance to the metal cone. In order to
correct this, they developed equations based on the
D’amours L; Savoie P. 2005. Density profile of corn silage in
stratum in which each measurement was taken.
bunker silos. Canadian Biosystems Engineering 47:2.21‒
Those authors observed that the SM estimation with
2.28. https://goo.gl/qLmluM
the penetrometer had greater accuracy when expressed as
Figueiredo GC; Silva AP; Tormena CA; Giarola NFB; Moraes
SMNM rather than as SMDM, while in our study the SM
SO; Almeida BG. 2011. Improvement of a testing apparatus
estimated with the indirect method showed greater
for dynamometry: Procedures for penetrometry and
accuracy when expressed as SMDM (R² = 0.80) rather
influence of strain rate to quantify the tensile strength of soil
aggregates. Revista Brasileira de Ciência do Solo 35:373‒
than as SMNM (R² = 0.57). The differences between the
387. DOI: 10.1590/S0100-06832011000200008
studies may be attributed to the range of uncontrolled
Holmes BJ; Muck RE. 1999. Factors affecting bunker silo
factors that may affect silage in silos on different farms
densities. University of Wisconsin, Madison, WI, USA. p.
(the study of Silva et al. 2011 was conducted under
controlled conditions on an experimental station); also,
Jobim CC; Nussio LG; Reis RA; Schmidt P. 2007. Avanços
the penetrometer used in the above-mentioned study was
metodológicos na avaliação da qualidade da forragem
a different model from the one we used.
conservada. Revista Brasileira de Zootecnia 36:101‒119.
After corrections considering silage stratum, Silva et
DOI: 10.1590/S1516-35982007001000013
al. (2011) found R² = 0.86 between the observed and
Nussio LG; Campos FP; Dias FN. 2001. Importância da
estimated SMNM and R² = 0.82 between observed and
qualidade da porção vegetativa no valor alimentício da
silagem de milho. Proceedings of the Simpósio sobre
estimated SMDM. Both Silva et al. (2011) and Vissers et
produção e utilização de forragens conservadas, Maringá,
al. (2007) concluded that the penetrometer is a reliable
2001. Vol. 1:127‒145. https://goo.gl/qik6JV
indirect method for determining the SM of maize silage.
Silva MS; Jobim CC; Tormena CA; Calixto Jr. M; Soriane
Our work confirms this conclusion and in addition
Filho JL; Roman J. 2011. Determinação da massa específica
corroborates that the penetrometer method is a simple tool
de silagens de milho por método indireto. Ciência Rural
that can be used on farm. The regression equation
41:1622‒1625. DOI: 10.1590/S0103-84782011005000114
y = -82.109x² + 257.9x + 89.182 (R² = 0.80) we developed
Storck L; Kobata SGK; Brum B; Soares AB; Modolo AJ;
for estimating SMDM using this penetrometer provided
Assmann TS. 2016. Sampling plan for using a motorized
good (80%) estimates of compaction of maize silage.
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However, how well this regression relates to other
Brasileira de Engenharia Agrícola e Ambiental 20:250‒255.
DOI: 10.1590/1807-1929/agriambi.v20n3p250-255
penetrometers and silage types needs further testing. Our
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data suggest that penetrometer measurements above 1.0
C; Cheng Q; Sun W. 2010. An improved penetrometer
MPa in maize silage indicate compaction above 250 kg
technique for determining bale density. Biosystems
DM/m3. However, more testing would be needed to
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confirm this rule of thumb. It was of interest that all
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Determining silage density on farms 99
Velho JP; Mühlbach PRF; Nörnberg JL; Velho IMPH; Genro
Vissers MMM; Driehuis F; Te Giffel MC; De Jong P; Lankveld
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1538. DOI: 10.1590/S1516-35982007000700011
(Received for publication 31 August 2016; accepted 22 February 2017; published 31 May 2017)
© 2017
Tropical Grasslands-Forrajes Tropicales is an open-access journal published by Centro Internacional de Agricultura Tropical (CIAT). This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported license. To view a copy of this license, visit
http://creativecommons.org/licenses/by-nc-sa/3.0/
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
Tropical Grasslands-Forrajes Tropicales (2017) Vol. 5(2):100– 102 100
Book Review
Tropical forage legumes: Harnessing the
potential of Desmanthus and other genera
for heavy clay soils
Edited by JOHN R. LAZIER and NAZEER AHMAD.
Published by CABI Publishing, Wallingford, UK, 2016.
480 pp. Price US$ 225.00. ISBN 9781780646282.
DOI: 10.1079/9781780646282.0000
Over 200 years ago, Thomas Jefferson, principal author
any new species to be invasive, both within and outside
of the American Declaration of Independence and the
the various regions in which they may be seen to have
third President of the USA, also a philosopher and farmer,
agronomic and economic merit (Williams and Burt
wrote: “The greatest service which can be rendered any
1982)”.
country is to add an useful plant to its culture”. This book,
The book describes the process followed by Dr. Burt,
“Tropical forage legumes”, highlights the complexity of
his co-authors and others to expand the range of legumes
the process in domesticating species, and the remarkable
available for use on heavy clay soils in the tropics, using
work of one person in particular, Dr. Robert (Bob) L.
the range of soils and climates found in Belize and
Burt, in adding a useful plant to our culture.
northern Australia as examples. Commendably, they did
The book itself has a somewhat poignant background,
not feel constrained by the prevailing dogma that would
in that two of the initial authors, Dr. Burt and Professor
have limited them to a particular group of already
Nazeer Ahmad, died before the book was published.
recognized forage legume genera, including Desmodium,
Dr. Lazier, himself a scientist of note, and also a friend
Macroptilium and Stylosanthes, many of which had been
and colleague of both great professionals, persisted with
selected for acidic soils in the subtropics . The book
the submission out of friendship and the recognition
comprises a total of 19 chapters, largely written as journal
of the need to make the information available to others
papers with Abstract, Introduction, Materials and
working in this general field. Dr. Lazier writes: “Since
Methods, Results, Discussion and Conclusions.
this research was undertaken there has been a marked
The first 9 chapters by various combinations of Burt,
decline in the funding for such research, and with the
Lazier and Ahmad covered all aspects of the work, from
retirement of experienced researchers much of this
collection of wild-type legumes in the Yucatán Peninsula
information will be lost. This volume has been written
region of Belize, Guatemala and Mexico, as well as in the
in order that new scientists in this field will not be
Caribbean islands, to the very involved methodology of
repeating work which has already been done, and can
identifying appropriate genotypes for evaluation, and
build upon the results. Recommendations are provided
ultimately to the evaluation programs in Belize and
for further research.” Recurrent themes are that: many
Australia. While much of the statistical methodology
areas of legume species diversity remain uncollected;
might have limited appeal to many readers, the actual
potentially valuable genetic material is being lost
philosophy and techniques involved in the distillation
through global warming and increasing agricultural and
process, together with the range of genotypes
urban development; and there is an urgent need to
investigated, will have broader appeal. The authors make
conserve remaining material before it is lost completely.
the point: “It follows that if genetic material is to be
It was gratifying to note that the authors favored a
selected for trials, for use as ‘core collection’, or
responsible approach to plant introduction, particularly in
‘representative range’, it cannot be done solely on the
relation to weediness. “Attempts to meet this demand
basis of geographic or provenance data. A meaningful
(adapted legumes) have, in fact, been made for some time,
classification is required.” Krull and Borlaug made a
with the due regard that must be paid to the potential of
similar observation in 1970: “The major hurdle to
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
unlocking the secrets (of our genetic resource collections)
necessary to ensure seed production would not be a
has been our inability to classify the variability.” Various
constraint to release and adoption, and to address other
approaches to overcome this hurdle are proposed and
issues such as establishment, plant nutrition, nodulation
discussed.
and management. Once again, Desmanthus was identi-
The research homes in on two species groups in
fied as a source of adapted germplasm for pasture, along
particular, Stylosanthes hamata and Desmanthus spp.,
with another of the species discussed by Burt, initially
although a number of other species are put forward as
known as Stylosanthes sp. aff. scabra and subsequently as
being worthy of further evaluation. It should be remem-
S. seabrana. While traditional species such as Lablab
bered that the reported work was conducted in the 1970s
purpureus were unsurprisingly successful for short-term
and 80s, and results and discussion need to be interpreted
leys, two species, which had been rejected from earlier
in terms of the state of knowledge at that time. It is
evaluations in favor of more persistent species, found a
interesting to note that a number of species identified in
significant role in ley pastures on clay soils – Clitoria
the various studies reported have subsequently been
ternatea and Macroptilium bracteatum.
absorbed into international tropical agricultural systems,
The aim of plant evaluation is to bring new and useful
often as a direct or indirect consequence of the work. As
germplasm into our culture, whether it be for immediate
well as Stylosanthes hamata and Desmanthus spp. in
use by humans or livestock, or to inject a measure of
grazing systems, Desmodium cinereum (long known
sustainability into current management or production
incorrectly as Desmodium rensonii), which they flagged
systems. On this basis, Chapter 11 provides an interesting
as a species of interest, is widely used in legume
case study of how Dr. Chris Gardiner from the James
hedgerows in Southeast Asia for erosion control and live-
Cook University, Townsville, Queensland, capitalized on
stock feed. Calopogonium caeruleum and Centrosema
Dr. Burt’s earlier work in the northern part of the State,
plumieri, considered as having forage potential, have
by visiting the evaluation sites established in the 1980s,
been rejected in this role due to low palatability, but are
and collecting and identifying legume species, largely
successfully used as green manure cover crops under
Desmanthus, persisting in this particularly testing
plantations. The Australian experience with the shrub,
environment – heavy clay soils and low, unreliable annual
Codariocalyx gyroides, was similar to that in Belize; it is
rainfall. This means he started with genotypes that had
very palatable but brittle and fails to persist under grazing.
persisted for around 20 years under commercial
The ubiquitous creeping legume, Desmodium incanum,
management in the target environment. Drs. Burt and
has not been adopted commercially despite being
Lazier had already done the painstaking work of selecting
promoted as a grazing legume (Kaimi clover) in Hawaii
genetic material that had a good chance of performing
as early as the 1940s. The mimosoid shrub/small tree,
well in this environment. In the ensuing period, Dr.
Acacia angustissima, attracted some attention in
Gardiner and others have undertaken a range of studies to
Australia, but was found to be unpalatable and showed the
evaluate the most promising varieties, and to define
potential to become an environmental weed.
aspects of their agronomy and productivity necessary to
Chapter 10 by Dr. Kendrick Cox from the Department
proceed to commercial release through a partnership with
of Agriculture and Fisheries, Queensland, summarizes the
a private company. Accordingly, a mixture of 5
significant volume of work carried out in Queensland,
Desmanthus selections (three of D. virgatus and one each
Australia, seeking legumes to fulfil a range of roles on
of D. leptophyllus and D. bicornutus) is being made
alkaline clay soils, mostly in the subhumid and semi-arid
available to producers under the Progardes trade mark.
areas in central and southern parts of the State. Most of
This chapter highlights the value of returning to
the previous work focused on selecting grazing legumes
discontinued evaluation sites if persistence is one of the
for the acidic infertile soils of the more humid coastal
key criteria of merit in selecting useful genotypes, and
strip. The research covered in this chapter had two
conversely demonstrates the folly of expecting to select
primary purposes: (1) to identify legumes to supplement
persistent plants from short-term experiments.
the limited suite of species that could be used in pasture
In the final chapters, Dr. Lazier focuses again on the
leys to build up the level of labile soil nitrogen in
situation in Belize, a small country of only 23,000 km2,
preparation for subsequent cropping; and (2) to identify
about 1/5 the size of neighbouring Guatemala. He
legumes that could persist in pastures, particularly the
initially outlines the development of the beef industry in
large areas of buffel grass ( Cenchrus ciliaris) that were
the country, identifying constraints to its expansion, one
becoming less productive as nitrogen became increasing-
being limited forage development. He follows up the
ly bound up in the extensive fibrous root system of the
industry review with an analysis of native pastures, in
grass. Within each of these, additional research was
terms of both botanical and chemical composition, and
Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)
102
finally a series of experiments comparing the more
should be A. pintoi. There are other name changes and
productive native legumes with a range of exotic species.
misspellings in the book, but it is not the role of a reviewer
As in the earlier chapters, Dr. Lazier’s work provides a
to act as proof reader. These are mentioned merely to
roadmap of how researchers can approach a forage
draw the reader’s attention to the issue, in order to prevent
development program in an untested area. As with any
perpetuation of incorrectly spelled names.
roadmap, there are usually a number of ways to reach
This is not a text. It is a book that will appeal to people
one’s destination. It is now over 40 years since he
involved in the search for new species to play a role in the
commenced his work in Belize, in which time alternative
development of sustainable agricultural production
methodologies have been developed for evaluating plants,
systems. While it focuses on legumes for alkaline clay
which may have produced slightly different outcomes,
soils, potential readership should not be limited to those
partly through using different comparators, but also
interested solely in legumes or alkaline clay soils. There
through using non-destructive sampling.
are many facets to this publication – legume species, soil
A note of caution – some of the species names used in
chemistry, plant ecology, field and statistical method-
the book are those that would have been applied in the
ology, seed production and philosophy, not to mention a
1970s. Although many appear to have been brought into
brilliant bibliography. Even the multitude of tables, that
line with the currently accepted taxonomy, some have not,
some may find tedious, provide detail for others that
e.g. the common centro mentioned in the book is listed as
might not be available elsewhere. I cannot in all honesty
Centrosema pubescens but is now accepted as C. molle,
say that this is a book that should grace the shelves of
while C. pubescens is now applied to cv. Belalto; many
every student of leguminology, but it should be consider-
former Cassia spp. are now classified as Chamaecrista or
ed a must for libraries associated with agricultural R & D
Senna; Macroptilium longepedunculatum is now
agencies around the world in both the tropics and
accepted as M. gracile; the Arachis pusilla referred to was
subtropics.
actually misnamed in the Australian collection, and
should be Arachis triseminata. There are misspelt names
such as Desmodium cinerium, which should be
Bruce G. Cook
Desmodium cinereum, Stylosanthes sympodiales, which
Agricultural consultant (former Research Agronomist)
should be S. sympodialis, and Arachis pintoii, which
Westlake, Qld, Australia
(Published 31 May 2017)
© 2017
Tropical Grasslands-Forrajes Tropicales is an open-access journal published by Centro Internacional de Agricultura Tropical (CIAT). This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported license. To view a copy of this license, visit
http://creativecommons.org/licenses/by-nc-sa/3.0/