dc.description.abstract |
Soybean is one of the forage legumes it can be planted for high-protein feed, such as
grazing, haying, or ensiling. The objective of the experiment was to evaluate the effects of
fertilizer level and row spacing on soybean (Glycine max (L.) Merrill) agronomic
performance, forage yield, and nutritive value under irrigation conditions. The field study
was conducted in a factorial arrangement of randomized complete block design (RCBD)
using two factors (three-row spacing and four fertilizer levels) with three replications .The
row spacing 50, 60, and 70 cm were combined with 0, 100, 120, and 140 kg ha
NPS
fertilizer rates. Blended NPS (Nitrogen, phosphorus and sulfur) fertilizer was applied at the
time of planting for all treatments. The agronomic characteristics and forage yield data were
collected at 50% flowering stage, weighed (for yield estimation), dried, and then ground
subsamples taken for analysis of crude protein (CP), crude protein yield (CPY), ash, dry
matter, organic matter, dry organic matter digestibility (DOMD), fiber contents, in vitro dry
matter digestibility (IVDMD) and metabolizable energy (ME). The collected data were
subjected to a general linear model for statistical analysis system (SAS) version 9.0. The
result indicated that there was significant interaction (P < 0.05) effect in the fertilizer level
and spacing only in the number of nodules, but for nutritional value of forage soybean DM,
CP, CPY, and ME. had an interaction effect. Both spacing and NPS fertilizer application
showed significant differences (P < 0.001) in the majority of agronomic characteristics like
-1plant height, number of branch, number of leaf per plant, number of nodule, dry matter yield,
and leaf to steam ratio. The agronomic parameters and nutritional quality had better
performance in 140 kg ha
-1
NPS application and 70 cm row spacing than in lower fertilizer
levels. However, the dry matter yield and crude protein yield were better on narrow (50 cm)
spacing. Overall, significantly (P < 0.001) maximum dry matter yield (12.2 t ha
) was
recorded from 50 cm row spacing, while the lowest dry matter yield (8.4 t ha
) was from 70
cm row spacing. Regarding fertilizer levels, maximum dry matter yield was recorded from
high-level NPS fertilizer application (10.9 t ha
-1
) while the lowest (8.7 t ha
) was recorded
from no NPS fertilizer application. The highest CP content (17.33%) was recorded from 140
kg NPS fertilizer application while the lowest (13.24%) was from no NPS fertilizer
application. The highest CP content was recorded from 70 cm row spacing (16%) while the
lowest CP (14.7%) was recorded from 50 cm row spacing. The highest net benefit (40212
birr) and the highest marginal rate of return (859.85%) from 140 and 100 kg NPS fertilizer
applications with 50 cm row spacing, respectively. Therefore, forage soybean with 100 kg ha
1
NPS fertilizer rate and 50 cm row spacing are given priority in terms of marginal rate of
return and are recommended for wider utilization under smallholder farmers' conditions in
the farming system with similar agro-ecologies using irrigation season. Animal evaluation
feed trial should be implemented to know the effect of the feeding value of forage soybean
[Glycine max (L) Merrill].
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en_US |