Adubação da sucessão soja e milho consorciado com brachiaria ruziziensis

Abstract

The predominant system production of Mato Grosso do Sul is the soybean and second corn succession crops in the no-tillage system. However, local climatic conditions prejudice the residue longevity at the soil surface, and consequently the introduction of Brachiaria ruziziensis in consortium with corn was an efficient management strategy that maintained the production of winter grains and pasture to cover the soil. Plant residues from pasture besides protecting the soil against erosive effects interfere at soil chemistry and humidity conservation that benefit the crop in succession. In view of the above, the objective of this work was to verify the productivity and the profitability index of the succession of corn crops (single or consortium with B. ruziziensis) and soybean with fertilizing application levels on seeding (0, 125, 250 e 375 kg ha-1 of 02-20-20 formula), besides the changes of soil chemical attributes at depths 0-0.2 m and 0.2-0.4 m and plant nutrition in the third crop (agricultural year 2013/2014) after the adoption of the practices. The experiment was conducted in Maracaju, MS, under a 2 x 4 factorial design with four replicates, being sown the materials DBK 390 VT PRO and BMX Power RR with specific fertilizer sowing (no-tillage) and haul application of the pasture seeds. The phosphorus levels in the soil increased with the levels of soybean fertilization, however the succession cultivation in no-tillage was also able to raise the initial contents of the nutrient in the soil, even in the absence of fertilization. Potassium saturation in the soil was influenced by the interaction of the treatments, and the best nutrient availability was verified by applying 125 kg ha-1 of the fertilizer in the soybean sowing on intercropping system. It was concluded that the quality of the system, evaluated by soil carbon content, was statistically higher when the maize intercropping system was adopted, due to the bigger contribution and supply of vegetable residues provided by the system. The profitability of the system was superior in the system with the pasture in consortium, being recommended for soybean sowing the replacement fertilization of the nutrients export, since the levels did not differ the profitability indexes due to the high fertility of the soil.