Maize productivity in succession to cover crops, nitrogen fertilization and inoculation with Azospirillum brasilense

摘要

The use of microorganisms in agriculture such as Azospirillum brasilense and the cultivation of cover crops in the off season, together with nitrogen fertilization, may be interesting alternatives to increase crop yield. The objective of this study was to evaluate the growth, production and nitrogen concentration of maize grown in succession to cover crops and their interactions with A. brasilense inoculation and topdressing mineral N fertilization. The experiment was conducted on Oxisol, in randomized block design in split-split-plot scheme with four repetitions. The plots consisted of four cover crops: jackbean (Canavalia ensiformis), dwarf pigeon pea (Cajanus cajan), crotalaria (Crotalaria spectabilis) and spontaneous vegetation. In the subplots, with or without inoculation of A. brasilense in maize seeds, and in the sub-subplots: with or without topdressing N fertilization. It was verified that jackbean can generate increments of up to 8.3% in grains per ear, 6.9% in length of ear and 15.2% in mass of one hundred grains. Consequently, the grain yield was higher in this treatment (18%). The inoculation with A. brasilense and topdressing N fertilization did not generate significant increments in maize production components, as observed for cover crops.