REPLACEMENT OF MACRONUTRIENTS WITH APPLICATIONS OF MOLYBDENUM IN PASTURE WITH NATIVE LEGUMES

Abstract

The objective of this work was to determine the interaction effects of replacement alternatives with chemical and organic fertilization (bovine manure) of macronutrients, with basal applications of molybdenum (Mo) and the contributions of native legumes on the performance of Brachiaria humidicola under cut. The treatments were: T1) without fertilization; T2) chemical replacement of extracted nutrients without including N; T3) chemical replacement of nutrients including 96 kg^.ha^-1.year of N; T4) chemical replacement and manure including 57 kg^.ha^-1.year of N contributed by manure; T5) similar to T4 plus 39 kg.ha^-1.year of N contributed by urea; T6) similar to T2 without legume. Four basic applications of Mo were made: at the beginning, at 2; 5,5 and 7,6 years. A split plot design with four repetitions was utilized for the analysis. Forage yield was 18,6; 16,3; 15,4; 11,9; 7,2 and 6,6 t^.ha^-1.year of dry matter (DM) for T5, T4, T3, T2, T6 and T1; respectively. Chemical nitrogen negatively affected the yield of native legumes at a rate of 11,13 kg of DM per kg of N applied. The contribution of the legumes in forage yield was 2,76 kg of DM per kg of legumes DM, contributing with 4,32; 5,51; 1,72; 4,71 and 0,95 t^.ha^-1.year of grass forage DM for T5, T4, T3, T2 and T1, respectively. The application of Mo improved the annual yield of legumes by 2,64 times, the response to urea by 12% and the response to native soil nutrients by 24%, contributing on average 23% of the forage yield.