Atributos físicos de um chernossolo conduzido sob diferentes sistemas de manejo

Abstract

Soil quality began to get more attention from scientific community in the 90s, when they realized the importance of this system to the agricultural ecosystem. Soil quality can be defined as the ability of a soil to present, in natural or agricultural ecosystems, ideal conditions for agricultural production. The physical and chemical properties are considered indicators of soil quality, because through these analysis is possible to identify whether there has been deterioration or improvement of the soil in relation to the management system utilized. The objective of this work was to evaluate soil quality through physical properties in five different management systems, which are these: native forest (MN), planted forest (FP), pasture (PAST), recent no till system (SPDR) and old no till system (SDPA). Disturbed and undisturbed samples were collected, where the deformed samples were stored in plastic bags until analysis, while the undisturbed samples were collected from soil core (physical analysis) at depths of 0-5, 5-10 and 10- 20 cm, with three repetitions each, totaling 9 samples per system, with a total of 45 samples. The results were submitted to analysis of variance by Tukey test at 5% of probability, where soil density and penetration resistance values were higher in the recent no till system (SPDR), old no till system (SPDA) and pasture (PAST) due to the increased land use and the pressure made by the traffic of machines and animal trampling, interfering in soil porosity and hydraulic conductivity. Macroporosity showed higher values in the recent no till system (SPDR), planted forest (FP), and native forest (NF), and presented a lower value in the pasture (PAST) and old no till system (SPDA), while microporosity was higher in the pasture (PAST) and smaller in the recent no till system (SPDR), which means the drainage is lower, whereas at higher levels of macropores the soil is well drained and aerated. On the other hand, the soil carbon (CO) had significantly higher average content in native forests (MN) in relation to other systems, which is explained by the high capacity of forests in retaining carbon to soils. The physical soil properties are closely interconnected and are directly altered by soil management. Therefore, well managed soils minimize its degradation, which causes improvement in their quality and consequently better crop yields.