Tropical Grasslands-Forrajes Tropicales (2017) Vol. 5(2):7784 77

DOI: 10.17138/TGFT(5)77-84

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.

5.923.929

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-

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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.

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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

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.

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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/

Qsx0gi

indicator of forage quality. Both limitations of this study

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could be addressed in future studies.

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(Received for publication 26 December 2016; accepted 26 March 2017; published 31 May 2017)

© 2017

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Tropical Grasslands-Forrajes Tropicales (ISSN: 2346-3775)