Épocas de dessecação da pastagem e escarificação influenciando a atividade microbiana do solo e produtividade de grãos

Abstract

The objective of this study was to evaluate drying times of the previous pasture to soybean cultivation, associated with physical intervention (scarification), through impacts on soil microbial activity in soil and grain yield in the livestock farming system integration. The experiment was conducted in soil classified as Acrisol dystrophic. The experimental area was occupied by the species Urochloa brizantha (cv Marandu) with five years of implementation. The experimental design was a split tracks, onstituting a double factorial 5x2. The plots consisted of five periods of desiccation of grassland (150 DBS - days before soybean sowing; 120 DBS, 60 DBS, 30 DBS and 15 DBS) and the subplots, with and without soil scarification. Were grown two production cycles of soybean and maize, soil samples being collected at the beginning of each production cycle for biological, chemical and physical analysis of fertility. plants were collected for nodulation analysis. At the end of each production cycle crops were evaluated for productivity parameters. The longer periods of early pasture desiccation provided gains in microbial activity in the soil, the first year of cultivation of soybeans and corn. There were also improvements in soil fertility indicators. In the second year of cultivation of soybeans and corn gains in quality indicators were lower compared to the first year of cultivation. Early pasture desiccation in 150 days before the soybean crop yielded considerable nodulation and soybean yield gains. The yield of corn after the first crop of soybeans, was significantly influenced by longer periods of anticipation desiccation performed before soybean cultivation.