Reference values and soil quality in areas of high soybean yield in Cerrado region, Brazil

The increasing demand of society for agricultural products and environmental services, charges agriculture a convergence between productivity gains and soil quality. In view of this, the establishment of boundary values for productivity and for soil quality in areas of high productivity and under conservation management systems were the target of this study. The objective of this study was to obtain reference values for the chemical, physical and biological properties of areas under no-till (NT) management in the southern region of the state of Mato Grosso, Cerrado region, Brazil. A total of 65 commercial soybean crop areas were sampled at the 0.0-0.10, 0.10-0.20 and 0.20-0.40 m layers. The productivity of the stands selected for the study was higher than the state average (3.32 Mg ha(-1)) and the national average (3.29 Mg ha(-1)). In 26 of these areas, which represented environments of high soybean yield, the 3-year average productivity in 2015, 2016 and 2017 was above 4.2 Mg ha(-1). The use of a quantitative regression analysis was an effective way to obtain the limits of the interval that is considered adequate to assure high productivities for each property. Among the 75 replicated variables obtained from 29 soil properties of three layers, 18 were significant for soybean yield. The soil properties that were significant in at least one of the layers were acid phosphatase, calcium, magnesium, potassium, the S index, the soil water retention curve (SWRC) inflection point, field capacity, pH (H2O), the available water capacity, bulk density, particle density and base saturation. The reference values of the soil properties that are suitable for productivity are also indicators of good soil quality. These results indicate a convergence between a high productive potential and good soil quality, which was explained by the impact of the NT system on soil quality in the studied areas.