Produtividade da soja inoculada com Bradyrhizobium e Azospirillum e atributos químicos e físicos do solo em sistemas integrados de produção

Abstract

The search for systems that intensify the use of the production area, in order to preserve the attributes of the soil and that promote the system and the production environment, have been a contributing factor for Brazilian agriculture of quality and productivity. The work was to evaluate the productivity of soybean and co-inoculated in modification of these integrated systems of production in the autumn-winter with objectives of this culture of autumn-winter in the chemical and physical attributes of the soil. The study was carried out in the area of Embrapa Agropecuária Oeste, in the 2018-2019 experimental crop due to the cultivation of improvements. The new cropping systems were allocated to the plots, with pasture years: 5,5; 4,5; 3,5; 2,5; 1,5; soybean variety corn off-season, rotations with cowpea brachiaria and corn-brachiaria intercropping in autumn-winter. As subplots were composed by the methods of inoculation via seed: 1) without inoculation (control), 2) inoculation with Bradyrhizobium and inoculation with Bradyrhizobium japonicum and Azospirillum brasilense. In the sub-subplots, two times of desiccation of Brachiaria were considered, at 28 and 11 days before soybean sowing. For the studies of soil attributes, the experimental design was in randomized blocks in subdivided plots, the plots being the cropping systems already mentioned and the subplots depths from 0,0 to 0,40 m, in layers of 0,10 m. Data were submitted to analysis of variance (p≤0,05) and means were compared by Tukey test for comparisons of inoculation and desiccation treatments and Skott-Knott test to compare production systems. It was observed that the shorter interval between desiccation of autumn-winter crops and soybean sowing increases the efficiency of soybean coinoculation with Bradyrhizobium+Azospirillum. In systems of succession and crop rotation in autumn-winter, early desiccation promotes an increase in soybean productivity, while the time of pasture desiccation does not interfere with soybean productivity in sequence. For soil attributes, it was observed that the use of pasture as an alternative for cultivation in autumnwinter does not change its physical quality, while crop rotation allows improvements in physical attributes, mainly improving microporosity. The cultivation of pasture in succession to soybean for a longer period promotes the maintenance of soil fertility. Crop rotation increases the chemical attributes of the soil, mainly in the surface layer, being effective in the nutrient cycling process.