Respuesta del Theobroma cacao L. a la roca fosforica en el norte de Chiapas, Mexico.

espagnol; castillan. En una plantacion comercial de cacao en condiciones de temporal, ubicada al norte de Pichucalco, Chiapas, se llevo a cabo un estudio de fertilizacion con nitrogeno, fosforo y potasio para incrementar el rendimiento de grano por medio de un fertilizante fosfatado de bajo costo y efecto residual prolongado en el suelo, como lo es la roca fosforica. Se realizaron 15 recolecciones y se obtuvieron de 12 200 a 23 400 frutos sanos y maduros por hectarea, equivalentes a una produccion de 570 a 956 kg de grano seco. Se cosecharon 306 kg de grano seco mas, al aplicar 50 kg ha**-1 de P2O5 como superfosfato triple de calcio, respecto a no aplicar fosforo. Al aplicar P en forma de roca fosforica se manifesto un incremento en el rendimiento de grano seco, en forma practica y directamente proporcional al aumento de la dosis de P2O5. Al comparar ambas fuentes de fosforo se encontro que con 50 y 750 kg ha**-1 de P2O5 como superfosfato y roca fosforica se produjeron 876 y 956 kg ha**-1 de grano seco, respectivamente. La roca fosforica calcinada de San Luis Potosi fue mucho menos eficiente y con menor tasa de retorno al capital variable que el superfosfato triple de calcio.

anglais. In a commercial cacao plantation under rainfall conditions, located in the North of Pichucalco, Chiapas, a fertilization study was carried out with nitrogen, phosphorus and potasium, to increase the yield of grain using phosphate rock, which is a fertilizer of low cost and prolonged residual effect in the soil. Fifteen harvests were made, obtaining from 12 to 23 thousand healthy mature fruits per hectare, giving from 570 to 956 kg yield of dry grain. The application of 50 kg ha**-1 of P2O5 as triple superphosphate increased dry grain yield in 306 kg ha**-1. When phosphate rock was applied, an increment in yield of dry grain was observed, which in practice it was directly proportional to the increase in the P2O5 rate. When both phosphorus sources were compared, it was observed that with 50 and 750 kg ha**-1 of P2O5 as superphosphate and phosphate rock, dry grain yields of 876 and 956 kg ha**-1 respectively were obtained. The calcined phosphate rock of San Luis Potosi was much less efficient and with lower return rate to the variable capital, than the triple superphosphate.