Influence of phosphorus fertilization on input-cost relationship and crop efficiencies of soybean (Glycine max) in Kandahar, Afghanistan

A field experiment was conducted during the spring season of 2017, at the Afghanistan National Agricultural Science and Technology University, Kandahar, Afghanistan, to evaluate the effects of phosphorus fertilization on yield parameters, input-cost relationships and use-efficiency in soybean [Glycine max (L.) Merr.]. Six phosphorus fertilization treatments, viz. control (no P), 15 kg P O /ha, 30 kg P O /ha, 45 kg P O /ha, 60 kg P O /ha and 75 kg 2 5 2 5 2 5 2 5 P O /ha, were applied in 4 replicates. The highest seed yield (2.47 t/ha) was recorded with the application of 75 kg 2 5 P O /ha, the increase being ~34.3% over the control (no phosphorus). Similarly, cost of cultivation increased with 2 5 increasing rate of phosphorus (P), 75 kg P O /ha was the costliest treatment among the treatments. Application of 2 5 75 kg P O /ha resulted in the highest gross (163.9 103 /ha) and net returns (84.90 103 /ha) followed by 60 kg 2 5 P O /ha, however, the maximum benefit: cost ratio was recorded with 60 kg P O /ha. Further, the highest produc- 2 5 2 5 tion (19.5 kg grain/ha/day) and monetary (763.8 /ha/day) efficiencies were recorded with the 75 kg P O /ha. Simi- 2 5 larly, application of 30 kg P O /ha showed the highest agronomic efficiency (15.4 kg grain increased/kg P O ap- 2 5 2 5 plied/ha). Overall, P fertilization had positive effect on nodulation which in turn reflected in yield and also influ- enced production efficiencies.