INFLUENCE OF SOIL FERTILITY AND NPK FERTILIZERS ON SUGARCANE YIELD AND NUTRITION

In a NPK factorial experiment conducted on a first ratoon crop nitrogen alone was shown to have an effect on yields and, whatever the diagnosis method used, only nitrogen was deficient in the plant, even when the nitrogen application was high. The effect of nitrogenous fertilizers was significant on the N, P, Ca, Mg and S contents of the 3rd leaf (TVD) at 5 months of age and on DRIS indices. The soil fertility shows a high heterogeneity of total N, available P and exchangeable K. Only the soil potash fertility has an effect on the potassic nutrition of sugarcane. The threshold of 0.2 me for 100 g of soil divides clearly two soil classes in which the response to potash fertilizer is different.