Produtividade da soja e atributos químicos e físicos do solo em rotação com arroz irrigado

Abstract

In a systematized area in a plane without typical slope of the lowlands of the South Coast of Rio Grande do Sul, a study was developed with the aim of relating the productivity of the soybean crop to the depths of the cuts and fills caused by the systematization together with the chemical and physical attributes. For this, a regular grid of points (40 x 40 m) was used, 68 georeferenced points for physical analysis of the soil and 56 for chemical analysis of the soil. The physical attributes analyzed were: density, humidity, resistance to penetration in the layers of 0.0 - 0.10 m, 0.10 - 0.20 m and 0.20 - 0.30 m, macroporosity, microporosity and total porosity. The chemical attributes analyzed were: pHH2O, pH SMP, potassium (K), sodium (Na), phosphorus (P), calcium (Ca), magnesium (Mg), aluminum (Al), potential acidity (Al + H), content organic matter (OM), base saturation (V%), aluminum saturation (m%), effective CTC and potential CTC. The data were analyzed through descriptive statistics, through the elaboration of thematic maps and also through the principal components analysis to explain the interaction between soybean productivity, cut and fill caused by systematization and the chemical and physical properties of the soil. With the results obtained, no relationship was identified between productivity and cut and fill caused by the systematization of the soil and between productivity and chemical attributes of the soil, but was found a stronger interaction between physical attributes and soybean productivity. Finally, it can be concluded that the productivity of soybeans in lowland areas, systematized and used in no-tillage is more influenced by the physical attributes of the soil than by the chemical attributes and the cuts and fills caused by the systematization of the soil influence the spatial behavior of soil chemical attributes, with less fertility at cut points.