Abstract:
Common bean (Phaseolus vulgaris L.) is an important pulse crop in Ethiopia. The use of
appropriate plant spacing and optimum level of NPSB fertilizer application are the major
agronomic factors to improve the productivity and yield of Common bean. A field
experiment was conducted in Alle special district, Southern Ethiopia, during 2020 belg
(March- June) cropping season to determine optimum NPSB fertilizer level and intra-row
spacing on growth, yield and yield components of Common bean. The experiment was
laid out in randomized complete block design (RCBD) with (5*3) factorial arrangement.
The treatment consisted of five levels of NPSB fertilizer rates (0, 50, 100, 150 and 200 kg
ha-1
) with three levels of intra-row spacing (5, 10 and 15 cm) with three replications.
Results showed that NPSB fertilizer rates had significant effect on days to 50% flowering,
days to physiological maturity, plant height and hundred seed weight, while number of
total nodules, number of effective nodules, number of pods per plant, grain yield, above
ground dry biomass and harvest index were significantly influenced by the interaction of
NPSB and intra-row spacing, main effect of NPSB and intra-row spacing. However, seed
per pod was not significantly affected by all the main as well as interaction effects. The
shortest number of days to 50% flowering (37.5) and days to 90% physiological maturity
(75.7) were recorded from the control. The longest plant height (64.4 cm) was recorded
at 200 kg ha-1 NPSB. The highest hundred seed weight (31.5g) was recorded at
application of 100 kg ha-1 NPSB, while intra-row spacing had no effect on these
parameters. The highest number of total nodule (46.2) and highest number of effective
nodule (29.5) were recorded at NPSB of 150 kg ha-1
and intra-row spacing of 15 cm.
Significantly highest number of pod per plant (23.4), highest grain yield (2900 kg ha-1
)
and highest above ground biomass (12,533kg ha-1
) were recorded from 200 kg ha-1 NPSB
rate when interact with intra-row spacing of 10 cm. Similarly the highest harvest index
(49.6) was recorded at NPSB of 200 kg ha-1
and 15cm intra-row spacing. Based on
partial budget analysis, application 200 kg ha-1 with intra-row spacing of 10cm gave the
maximum net benefit of 73,980 ETB birr with marginal rate of 3491. Therefore, based on
this study the application of 200 kg ha-1 NPSB fertilizer with 10cm intra-row spacing
observed to be the best option for economical and agronomical feasibility of common
