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
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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.
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However, these data do not present a complete picture as
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the pasture harvested early would regrow and the
and legumes). Longman, London, UK.
reduction in yield we observed would be much greater
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than actually would occur, where repeated cuttings would
ecology and husbandry. Kluwer Academic Publishers,
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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,
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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.
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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
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