FERTILIZATION AND PLANT ARRANGEMENT IN INTERCROPPED MAIZE AND BRACHIARIA

Abstract

The optimization of maize and Brachiaria intercropping managment is influenced by soil fertility, Brachiaria plant density, and maize plant arrangement. This research evaluated those factors interactions and their influence on the productivity of maize and Brachiaria. The experiment was carried out during two crop cycles, in a 2x2x3+1 factorial scheme, combining two conditions of maize fertilization (grain yield expectation of 6 or > 10 t ha^-1), medium or high plant density of Brachiaria (< 20 or > 30 plant m^-2), three maize plant arrangements (A = 90 cm row spacing with 5 plants m^-1; B = 45 cm row spacing with 2.5 plants m^-1; and C = 45 cm row spacing with 3 plants m^-1), and one additional treatment (heavier fertilization, without Brachiaria and maize A arrangement). Water availability influenced the responses to treatments. In the rainy year, heavier fertilization promoted expressive grain yield increase, independently of the maize arrangement or the presence of Brachiaria. In the dry year, the maize yield increase, due to heavier fertilization, was smaller and there was a harmful effect caused by the higher Brachiaria density. The dry matter yield of Brachiaria was not directly related to the variation in plant density.

KEY-WORDS: Crop management; crop-livestock integration; precision agriculture; row spacing; plant population.