Correlação da matéria orgânica e atributos físicos do solo com a produtividade do milho na microrregião de Pindaré-Mirim

Abstract

The aim of this work was to evaluate the spatial correlation between the quality of organic matter and physical attributes of the soil with the yield of the corn crop, aiming to increase the yield potential in structurally fragile soils in the microregion of Pindaré-Mirim. The experiment was conducted at the Technological Reference Unit – TRU in ICLF of EMBRAPA Cocais and UEMA, in the municipality of Pindaré-Mirim – MA, Brazil. In this experiment, the soil physical variables that have a significant correlation with the increase or limitation of corn crop production were evaluated. Total organic carbon (TOC), particulate organic carbon (COP), organic carbon associated with minerals (COAM) and soil physical attributes (soil density, total porosity, microporosity, macroporosity, resistance to penetration, moisture and composition) were determined. grain size) and corn yield (number of ears per plant, mass of 100 grains and ear weight), in 119 sampling points, in a uniform grid of 72 m2. The production evaluation was carried out in 6m2 around each sampling point. The deformed samples were collected at two depths (0-15 and 15-30 cm) and the undeformed soil collections were carried out in a 30 cm mini trench, at the same depths and at the same sampling points. The soil mechanical resistance to penetration was determined on the fourth day after the rain, with two collections per sampling point, together with the collection to determine moisture. The analyzed variables mostly showed normal distribution at both depths. COT, COAM and silt showed a positive correlation with productivity, on the other hand, RP, fine sand, coarse sand showed a negative correlation. By stepwise multiple regression analysis, the variables COAM and RP influenced maize yield, explained by the effect on the soil root growth zone and, consequently, on the roots. Based on the isoline maps, there was a similar behavior between yield and COAM in the 0-15 cm layer, and an inverse effect between RP contents in the northern and southern extremities of the area. different correlation with corn yield. As the levels of COAM increased, maize productivity increased, however, crop productivity decreased with increasing RP in the soil