Strategies for applying P fertilizers to upland rice in sloping uplands
2001
Tubana, B. (International Rice Research Inst., DAPO Box 7777, Metro Manila (Philippines)) Magbanua, R. | Hondrade, E. | George, T.
It is important that much of the nutrients from applied fertilizer find its way into crops and that minimum loss to the environment is incurred. Plant availability of phosphorus in the sloping uplands is limited due to its loss in eroded topsoil and due to its reaction with P-fixing soil. Studies were conducted to test the effectiveness of band-applied, resin-coated triple superphosphate (TSP) and foliar supplement of monopotassium phosphate (MKP) to upland rice. Phosphorus rates of 0, 25, and 50 kg P/ha were applied as coated TSP to improve upland rice in Siniloan, Laguna and MPK was applied (1.125 kg P/ha, four times) to traditional and improved upland rice in Arakan Valley, Mindanao, Philippines. Results show that while P fertilization tended to increase yield, coated TSP did not differ significantly from the non-coated TSP; at 50 kg P/ha, the former yielded 3.7 and the latter, 4.0 t/ha. In Arakan, foliar MKP significantly increased the yield of the improved, but not of the traditional rice. The improved varieties averaged 3.7 t/ha with MKP. A yield of 4.0 t/ha was obtained when PeaK + urea was applied (control had 3.4 t/ha). The effectiveness of both methods needs to be further evaluated before wider application can be considered
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