Micromorphological analysis of soil porosity under integrated crop-livestock management systems

Integrate crop-livestock systems has been an efficient alternative for food production contributing to environmental sustainability and soil conservation. The objective of this study was to characterize some micromorphological properties of a Humic Rhodic Hapludox in integrated production systems. For this, four soil tillage systems were evaluated: conventional (CT), minimum (MT), no-tillage (NT), and chiseled no-tillage (CNT), under two annual ryegrass uses: grazing (G) and silage (S) at two soil depths (0–0.10 m and 0.10–0.20 m). Information about the size and shape distribution of the pores were obtained through the micromorphological analysis to determine the imagery porosity. The smallest porosities were found in the top-layer, independent of the management systems and ryegrass usages. The complex shaped pores of larger sizes (> 1000 μm) had the greatest contribution to the imagery porosity in the sub-layer, although they were less frequent in the top-layer. Complex shaped pores were compressed due to the contrasting managements employed, decreasing their area and, consequently, influencing the fragmentation of this type of pores. As consequence, there was an increase in the amount of rounded shaped pores, especially ranging from 100 to 500 μm. The CNT management system improved the soil structure based on the results of porosity as well as the shape and size distributions of the pores.