Improved N and P fertilizer management increases the rice yields of small resource-poor farmers

摘要

The deep point-placement of nitrogen (N) as pillow-shaped urea briquettes (UB) after transplanting is an efficient N management practice in rice. But, the conventional basal application of water-soluble phosphorus (P) such as single superphosphate (SSP) is not an environmentally friendly fertilizer management practice because P in the floodwater and sorbed by clays in the surface soil is prone to surface runoff losses. There is an urgent need for simple, efficient and still affordable NP fertilizer management that small resource-poor farmers can use to increase the productivity of their small, fragmented, lowland paddy fields in rainfed regions. Using conventional prilled urea (PU) and diammonium phosphate (DAP), the authors prepared UB containing DAP (UB-DAP) (4:1, N:P) and evaluated their agronomic potential as an NP source for rainfed transplanted rice during the 1993,1994 and 1995 wet (southwest monsoon) seasons on tribal farmers' gelds in a warm subhumid tropical region on the west coast of Maharashtra State, India.