Qualidade física de um Latossolo estimada por estudos das curvas de retenção de água, indicadores de fácil determinação e “Índice S”

Abstract

The objective of this work was to evaluate the physical quality of an LVdf under different management systems by analyzing soil water retention curve (SWRC), physical attributes of easy determination and S index. The experimental design was completely randomized, with four managements (native forest, corn, coffee and eucalyptus) and five replications, totaling 20 samples. To obtain the SWRC, samples with preserved structure were prepared and submitted to potentials of -2, -4 and -6 kPa in the suction units, -10, -33, -100 kPa in Richards' chambers, and -500 and -1500 kPa in the Psychrometer Thermocouple (WP4).From the SWRC the pore distribution by size was quantified and the attributes of the physical quality of the soil were calculated: macro and microporosity, total porosity and S index. Soil bulk density (Bd) was determined by the volumetric ring methodology. The available water capacity (AWC) was obtained by the difference between the water contents in the field capacity and the permanent wilting point. The Bd influenced the water retention of soils managed with corn, coffee and eucalyptus. The SWRC, Bd and porosity were shown to be good indicators of physical quality, but the S index did not show sensitivity in the diagnosis of the structural modifications resulting from the use and management of the soil. Management systems have promoted an increase in the available water capacity of the soil.