Fertilization with Nitrogen, Phosphorus and Potassium in Upland Rice Cultivars in the Southern Region of Rondônia, Brazil

Abstract

The upland rice productivity in the state of Rond?nia is still low, in view of the potential of culture. The use of cultivars adapted to different regions and more responsive to fertilizer employed is an essential practice which can change that. The aim of this study was to evaluate the agronomic characteristics and productivity of two upland rice cultivars with nitrogen, phosphorus and potassium (N-P-K) doses in two municipalities in the southern state of Rondonia region. The experimental design was a randomized block design with four replications in a factorial 2 × 2 × 5, with the first factor composed of two cultivars (hybrid Ecco and conventional farming AN Cambará), the second factor, the environment of the two municipalities, Cerejeiras and Vilhena and the third factor of five doses of N-P-K (0-0-0, 30-40-30, 60-60-60, 90-90-90 and 120-100-120 kg·ha -1 ). The characteristics evaluated were: tillering, number of integers and sterile grains per panicle, weight of 1000 grains, grain yield (kg·ha -1 ) and whole grain yield. There was no triple interaction between the three factors for any of the traits. The hybrid Ecco has higher tillering ability than AN Cambara and presents fewer sterile grains per panicle, heavier 1000 grains and hence greater productivity. For both cultivars, the highest yields are obtained with a dose of 120-100-120 kg·ha -1 N-P-K. For the Ecco, the productivity is achieved with this dose and the dose of 90-90-90 kg·ha -1 is statistically similar. There is no difference in productivity between the municipalities when the dose of N-P-K is less than 60-60-60 kg·ha -1 . The highest yield of whole grains in function of N-P-K fertilization is obtained in Cerejeiras.