Use of controlled availability fertilizers (CAF) in the production of rice, corn and legumes on lahar
1995
Samonte, H.P. | Shoji, S. | Nanzyo, M. | Chino, M. | Kimura, K. | Ocampo, A.M. | Willaver, J.
Results for two croppings of rice showed the following: a) without fertilization rice yield will be zero and adding 150-150-200 conventional fertilizer produced 0.56 ton/ha, b) addition of CAF NK + P increased the yield by 1.2 tons/ha, a 214 percent increment. This was still lower than the yield on soil + conventional fertilizer. High rate of chicken manure was not beneficial. After three croppings the effect of CAF on corn are as follows: a) CAF NK + P increased the grain yield by 3.4 tons or 179 percent over the control, b) it also increased the yield by 14 percent over the conventional fertilizer. The cumulative nutrient release pattern of POCU 70 was 25, 35, 47, and 82 percent at 21, 42, 64, and 85 DAP for rice. With corn, it was 14, 28, 34, and 79 percent for corn for the same sampling periods. The rice varieties tolerant to low Fe on lahar were IR66 and PSBRC 4. The suitable legume varieties were: BPI P9 for peanut, CP 5 for cowpea and IPB M79-17-91 for mungbean. The optimum fertilization rate for peanut was 70-60-70 supplemented with chicken manure. Iron deficiency could by controlled by split application of 50-62 kg Fe/ha. The evaluation of iron fertilizers using pot experiment was not conclusive since the severe deficiency symptoms observed in the field plots were not observed in the control pots. Only 5 kg Fe/2 x 10 to the sixth power kg was needed to correct Fe deficiency in the pot. Further studies are needed to evaluate the effects of different rates of CAF and Fe supplemented with organic fertilizers at varying depths of lahar in the field
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