On-farm economic and agronomic evaluation of nitrogen and phosphorus fertilizer use in snowpeas in Kabaru, Kenya

A trial was carried out at Kabaru to develop agronomically optimum and economically appropriate application rates for nitrogen and phosphorus fertilizer. Factorial combinations of 0, 130, 230 and 280 kg/ha P 2 O 5 applied as triple superphosphate at planting, and 0, 70, 140, and 180 kg/ha N applied as calcium ammonium nitrate for topdressing were tested. The experimental design used was randomised complete block design. Soil was collected and chemically analysed. Results showed 7.9 pH, 0.24% N, and 6.2 ppm P. The treatment effects were not significantly different at 5% level of significance. The highest pod yield of 8.1 t/ha and net benefit of K. sh. 112,127/ha was obtained with the application of 130 kg P 2 O 5 + 70 kg/ha N. The farmers’ acceptable minimum rate of return (AMRR) of over 100% was obtained using the same rate hence the recommendation for farmers at this site for snowpeas is 130 kg/ha P 2 O 5 and 70 kg/ha N.