ATRIBUTOS BIOQUÍMICOS EM DIFERENTES SISTEMAS DE MANEJO DO SOLO

Abstract

Increasing productivity in the same production unit requires the use of production technologies that guarantee the good development of crops. Thus, the use of intercropping in the no-tillage system stands out due to the increase of straw on the soil surface, which tends to benefit the system and is necessary as an option to recompose the soil biodiversity, constitutes a reserve, and contributes to nutrient recovery and cycling. But after long periods of harvest (corn and soybeans) without intercropping, the soil can express factors that can impact crop productivity, so it is essential to analyze soil fertility through its chemical and biological attributes. The objective of this work was to evaluate biochemical attributes under different intercropped systems after three years in a no-till soybean system in Southwest Goiano, Brasil. The treatments evaluated were maize in monoculture, maize intercropped with Urochloa ruziziensis, with Urochloa brizantha cv. Marandu, U. brizantha cv. BRS Paiaguás and sorghum intercropped with U. ruziziensis. The evaluations of chemical attributes were pH, H+Al, Ca2+, Mg2+, P, K+ and organic carbon, and the biological attributes were C-BM, N-BM, basal respiration, qCO2, qMic, β-glucosidase, arylsulfatase, phosphatase acid, urease and fluorescein diacetate. Data were analyzed using analysis of variance, and means were compared using Tukey's test (5%) and principal component multivariate analysis (PCA). Chemical and biological attributes are affected by management. It was observed that pH was not influenced and that K+ was influenced by intercropping with cover crops in both areas. At farm Boa Esperança, in Montividiu, GO the P was the chemical attribute that was not affected by intercropping, with the best response in monoculture. C-BM, N-BM and qMic in Rio Verde, GO, and C-BM, RB, qCO2 and qMic in Montividiu, GO, obtained some higher cultivation than the monoculture in the rainy period. The β-glucosidase and arylsulfatase enzymes were the most sensitive to handling, in relation to other enzymes evaluated. The enzyme β-glucosidase in the rainy period evaluated in Rio Verde, GO, Brasil, showed a better response on U. ruziziensis, but did not maintain the same behavior during the transition to the dry period. The arylsulfatase enzyme was not able to demonstrate an effect in treatments intercropped with U. ruziziensis brachiaria.