Qualidade do plantio direto em estabelecimentos rurais do sudoeste do Paraná

Abstract

The “Sistema Plantio Direto” (SPD) or “No-Tillage System” (NTS) is an agricultural production system that promotes environmental and productive quality to the soils, having as premises the use of no-tillage practice, permanent soil cover, and crop rotation. “Plantio direto” (PD) or No-Tillage (NT) refers only to the absence of soil tillage, which currently predominates in grain crops, compromising soil quality. The NTS's Participatory Quality Index (IQP) is a methodology for evaluating and managing the quality of the SPD, analyzing the conservation practices adopted. From eight indicators, the IQP generates a score from 0 to 10, with a higher value related to the better quality of the SPD. The IQP is in the IQP 2 version, and the IQP Sudoeste-PR is proposed, which considers regional specificities. The aim of this work was to evaluate and validate the use of the IQP in this region. Still, it aimed to propose parameters that allow the characterization of the SPD from the IQP, differentiating it from the PD. The study was conducted in 13 plots of farmers in the Southwest-PR with grain crops, in the year 2021. Information on the management of the plots was collected through interviews with a structured form, with determination of IQP 2 and IQP Sudoeste-PR, and further analysis of the results. Also, physical attributes (bulk density, total porosity, macroporosity, microporosity and soil structural quality index) and chemical attributes (pH, m, Al, Ca, Mg, K, P, V and MOS) were determined, which were compared with levels of suitability for agricultural production. Finally, the data from IQP 2 and IQP Sudoeste-PR were correlated with chemical and physical attributes. The average values of IQP 2 and IQP Sudoeste-PR of the stands were 7.49 and 7.41, respectively, classified as good, but with a predominance of the adoption of PD only. Both versions indicated problems related to the use of crop rotation, insufficient straw production and the adoption of terracing. For the physical and chemical attributes, there were no restrictive levels for agricultural production, highlighting the formation of gradients in the soil profile, differentiating a superficial layer (0-8 cm) with higher nutrient contents and lower densities, from a subsurface layer (8-20 cm). Both IQP 2 and IQP Sudoeste-PR were correlated with chemical and physical attributes, proving to be suitable for use in the region, with the IQP Sudoeste-PR being the most opportune due to better identification of crop rotation. From the IQP Sudoeste-PR, SPD can be differentiated from PD, adopting the definition of SPD as a cropping system without soil preparation for a period longer than eight years, having in the last three years the cultivation of four or more plant species, the cultivation of four or more species of Gramineae family, and a maximum of eight non-continuous months without the cultivation of plant species along three years.