Biomass Yields and Nutritive Composition of Leucaena Varieties in Irrigated Lowland of Dassench Woreda of South Omo, South-Western Ethiopia

“The overall productive and reproductive performances of livestock in Ethiopia are generally very low” [1-3]. Likewise, the poor-quality feeds and inadequate supply of feed biomass from the grazing-land (natural-pasture) to livestock in South Omo Zone are one of the important element that are contributing to low outputs (milk, meat and growth rates) from the livestock [4,5]. It seems that the nutritive values generated from the grazing-lands are seriously affected by dynamics of pasture-forages [5,6]. Hence, nutritive values from the extensive-grazing-lands do not realize the crude protein and energy demands of livestock. “This is activating to escalation great slow growth rates, high mortality, longer calving intervals and substantial weight loss” [7,8]. The supplementary feeding system is the addition of some feeds that are rich with vital nutrients to low-quality-forage to improve the intake and digestibility of low-quality forages aimed for higher outputs from animals. The evaluating and familiarizing of locally adaptable improved forages-crops to supplement the extensive-pasture-grazing system for pastoral and agro-pastoral areas is only the way to engulf feed shortages [4,5]. The Leucaena species is one of legume fodder trees, which is evergreen, highly branched and have a fast-growing potential, which grows up to a height of 5m to 20m [9]. It well adapted and better yielded in a wide range of rainfall environments which ranging from 6503,000mm with warm temperatures ranging from 25°C to 30°C [10]. ARTICLE INFO ABSTRACT


Introduction
"The overall productive and reproductive performances of livestock in Ethiopia are generally very low" [1][2][3]. Likewise, the poor-quality feeds and inadequate supply of feed biomass from the grazing-land (natural-pasture) to livestock in South Omo Zone are one of the important element that are contributing to low outputs (milk, meat and growth rates) from the livestock [4,5]. It seems that the nutritive values generated from the grazing-lands are seriously affected by dynamics of pasture-forages [5,6]. Hence, nutritive values from the extensive-grazing-lands do not realize the crude protein and energy demands of livestock. "This is activating to escalation great slow growth rates, high mortality, longer calving intervals and substantial weight loss" [7,8]. The supplementary feeding system is the addition of some feeds that are rich with vital nutrients to low-quality-forage to improve the intake and digestibility of low-quality forages aimed for higher outputs from animals. The evaluating and familiarizing of locally adaptable improved forages-crops to supplement the extensive-pasture-grazing system for pastoral and agro-pastoral areas is only the way to engulf feed shortages [4,5]. The Leucaena species is one of legume fodder trees, which is evergreen, highly branched and have a fast-growing potential, which grows up to a height of 5m to 20m [9]. It well adapted and better yielded in a wide range of rainfall environments which ranging from 650-3,000mm with warm temperatures ranging from 25°C to 30°C [10].

ARTICLE INFO ABSTRACT
The average dry biomass yields of Leucaena species are ranges   from 3-30 tons/ha depending on soil, temperature, and moisture conditions [9]. The dried leaf of Leucaena species contained crude protein and metabolizable energy values which ranging from (230-288.6g/kg DM) and (10.27MJ/kg DM), respectively [11,12]. The sheep groups fed on basal diet of grass-hay and supplemented with diets contained dried Leucaena leaves with inclusion levels, ranging from 25-50%, showed higher daily feed intake and weight gain over non-supplemented sheep group [11]. "The Leucaena leaves meal or fresh leaves can also replace concentrate diets, since it increases total daily dry matter and protein intake, and thus improving growth rate of animals" [13,14]. Also, it was reported that the Leucaena foliage inclusion levels between 500g/kg, DM and 750g/kg, DM can be replaced concentrate diet without adversely affecting the growth and milk production performances in goats [15,16]

Experimental Site
On

Agro-Pastoral Research Extension Group (APREG) Formation
One APREG that comprised about 25 Agro-pastoralists was established with vigorous envelopments of experts from Woreda Livestock and Fisher Development Office by considering irrigationaccess, interest and irrigation capabilities of trial agro-pastoralists.
The selected trial Agro-pastoralists and experts were trained on forage agronomy and irrigation water management techniques.

Experimental Design and Variety
The five Leucaena varieties such as DZ-0032, DZ-321, DZdismounts, DZ-235 and DZ-032 were obtained from DZARC. A plot area sized 4m by 3m = 12m having about four rows and two seed per hole planted after treated seeds in water boiled at100 0 C for one minute to break dormancy of seeds. The spaces between plots and plant were 1m, respectively and the total area of trial site was 12x26m (312m 2 ). Thus, a total of about fifteen plots which each measured 12m2 sized were used in the present study. The randomized completed block design comprising three repetitions each variety was used and plots in each block were randomly assigned per variety. The 3kg/ha seeding rate were used without fertilizer application [17]. The surface irrigation was used, and all the plots were irrigated uniformly as per the intended irrigation schedule [17].

Experimental Site and Data Collection
The trial site was always kept weed-free by hand weeding and hoeing, and agronomic data like plant height and branches per plant were recorded when plants was at 50% blooming stages (28 weeks after planting) by taking nine plants from middle of three rows per plot. The average plant height was recorded from ground to the pitch of the main stem. To measure the biomass yields at 28 weeks, all leaves and sprouts were contemplated from the three collected middle row per plot, and fresh sample was recorded in field by using spring weight balance, and 500g sub-sample per plot was brought to laboratory and cut into small pieces. Then 300g of sub-sampled sample was allocated into oven dried set at 105oc temperature for 24hours for biomass yields determination [18].

Chemical Analysis
The nutritive values analysis was done at DBARC. Three leavessamples of each variety were put into oven dried which set at 65°C for 48h and crushed to pass comprehensive 1mm sieve size for chemical analysis. The laboratory analysis was conducted for different nutritive values (DM, Ash, CP, NDF and ADF). DM, CP and ash were investigated by "technique of [19]". The NDF value was evaluated by [20] while the ADF value was evaluated by process of [21].

Data Analysis
The data such as plant height, branches per plant, biomass yields, and nutritive values were subjected to analysis of variances using the Generalize Linear Model (GLM) [22]. The significant differences among the means of varieties were declared at p<0.05 and means were separated using LSD test with following model: ,

The reason for higher biomass yields for DZ-321 variety was
justified that variability genomic potential. In supports to result from the present study, the studies stated by [23] and [24] were showed that the difference in biomass yields among the forage crops is ascribed due to variances in hereditary potential of forage species. Moreover, "biomass yields variability for forage species could be reported due to varietal or biological potential" [25].
"These effects have been widely described for legumes in general [26] and Leucaena variety in particular" [27]. The biomass yields obtained from present study for all varieties were similar to reported average biomass yields which ranges from 10-30 tons/ ha under well fertile soil [28]. Also, similar biomass yields were perceived from this study to reported biomass yields of 2-13 tons/

Nutritive Values
The nutritive values of Leucaena varieties in Dassench Wored are presented in Table 2 in study area is due to "higher-genetic-potential which might be accounted to accumulate the high nitrogen contents from the given environments". The result on CP content obtained from our study for DZ-032 Leucaena variety was in agreement with the previously reported value of (23%) by Juma, et al. [

Conclusion
The DZ-321 variety gave higher biomass yields, while DZdismounts variety gave the lower biomass yields. However, the DZ-032 variety had higher CP and lower fibers (NDF and ADF), while DZ-dismounts and DZ-321 varieties were giving the lower CP. Thus, it can be concluded that herders in study areas can be planted DZ-321 variety for higher biomass yields, while DZ-032 variety for higher CP content.

Acknowledgement
The author greatly thanks the Bureau of pastoral affairs in Southern Nation, Nationality and People Regional State for fully covered cost of all expenditures for this research activity. Finally,

author acknowledged Dassench Woreda Livestock and Fisheries
Resource Development office, specialists and agro-pastoralists that fully participated during the investigation periods and made this research results to be successful.