Two field experiments were carried out during 1991-92 in Paranavaí and Altônia cities, Northwest of the State of Paraná, Brazil, in order to evaluate the yield response of cassava and soil chemical characteristics to NPK fertilizers and liming. On sandy Dark Red Podzol, soils have low fertility originated from geological formation of "Caiuá" sandstone. The experimental design was a randomized block with nineteen treatments and four replications. Treatments comprised nutrient rates of nitrogen (0, 20, 40 and 60 kg ha-1); phosphorus (0, 30, 60, 90 and 120 kg ha-1); potassium (0, 40 ,80 and 120 kg ha-1); and lime (0, 850, 1,700 and 2,550 kg ha-1). Yield of cassava roots was not influenced by liming and nitrogen and potassium fertilization. Potassium fertilizer did not contribute to increase the soil K levels. The P fertilizing increased cassava root production, P content in the soil after cassava cultivation, and was considered as essential in the cassava roots production in both sandy soils of the Northwest of Paraná.
Manihot esculenta; phosphorus; culture rotation; liming
