AgWise / Rwanda Rice / fertilizer recommendation

The Rwanda Agriculture Board (RAB), CGIAR demand partner in Rwanda, requested us to provide fertilizer recommendations by agroecological zone for rice production for two scenarios:

1. Reduce fertilizer but achieve current yields under blanket level recommendation
2. Achieve a 10% and 20% yield increase over current yield under blanket

A lot of crop response data were used in machine learning and crop models to develop recommendations that indicate that 15% less fertilizer can be applied to get the same yields as currently obtained. 

That is, 6 bags of fertilizer (4 bags of NPK 17:17:17 and 2 bags of urea; 50 kg each) can be replaced with 5 bags (1 bag DAP, 1.5 bags NPK 17:17:17 and 2.5 bags of urea). This is a reduction in K, and also results a 16% return on investment, given current prices.