Qualidade de um latossolo manejado com plantio direto sob rotações após três anos

Abstract

Soil quality can be estimated from its chemical, physical and biological attributes, and the physical indicators of soil quality are linked to management, such as crop rotation. Currently, Brazil has its economy based mainly on agricultural production, needing to seek more and more practices that contribute to the sustainability of this. Among the promising practices in sustainability is the crop rotation that assumes a prominent position as a form of conservationist production in the no-tillage system. Thus, the present study had as objective to evaluate the physical quality of the soil through the physical attributes and the soil organic carbon content in soil management systems. Soil density, total porosity, macro and microporosity, stability of stable aggregates in water, organic carbon content and visual analysis of soil structural quality were determined. The study was carried out in the Experimental Station of Farm Model - IAPAR, located in the city of Ponta Grossa, state of Paraná - Brazil. The soil of the area, according to the Brazilian soil classification system, was classified by the IAPAR soils research team, such as typical dystrophic OXISOL RED, medium texture.The experimental design was a randomized complete block design with six treatments and four replications, with plots consisting of 300 m2, 10 m wide and 30 long. The treatments were composed of six crop rotation options, with cycles of three years being: succession, producer, grains, phytomass, diversified and pasture. The structural quality evaluation in the two layers did not differ. The physical attributes were not influenced by crop rotation, the significant difference was restricted only in the evaluation of the soil layers, in which it presented higher surface values for organic carbon, total porosity and microporosity. With the results obtained it is concluded that the physical attributes, density, soil organic carbon content, total porosity, microporosity and macroporosity were not influenced by the rotation systems. The highest values of soil density were found in the depth of 0 - 0.2m. The highest total porosity and microporosity was at the 0 - 0.05m layer and at 0.2 - 0.4m, there was no difference of macroporosity at depth. The stability of aggregates was similar to each other. The organic carbon presented higher amounts to the depth of 0 - 0.1 m. In the visual analysis the Pasture Treatment was similar to the Phytomass and different from the other treatments. The phytomass treatment showed higher production of dry biomass. The treatment Producer only differed from the diversified with regard to soybean production.