The least limiting water range (LLWR) is one of the best indicators of soil physical quality in intensive production systems. The objective of this study was to evaluate the physical quality of a Typic Haplorthox by the LLWR after three crop growing seasons and the first year of crop-livestock integration in Xambrê, northwestern Paraná, Brazil. The experiment was established in a randomized block design with three replications. Treatments consisted of four brachiaria heights before grazing (0.10; 0.20; 0.30, and 0.40 m) and a control treatment without grazing. The brachiaria (Brachiaria ruziziensis) was sown in March 2010 and cattle grazed on it continuously for 110 days (March-September). In October 2010, 90 soil samples were collected with metal cylinders (height 0.05 m, diameter 0.05 m) from the center of the layers 0-0.10; 0.10-0.20; 0.20-0.30 m. These samples were used to obtain the water retention curve, the penetration resistance curve and the soil bulk density (Bd), from which the LLWR and the critical bulk density (Bdc) were calculated. The critical limits of -80 hPa for field capacity (θfc), -15,000 hPa for wilting point (θwp), 2.5 MPa for soil resistance to penetration (θsr) and 0.10 m³ m-3 for air filled porosity (θafp) were used. The LLWR was highest in 0-0.10 m and θsr was the most relevant variable to reduce LLWR in all layers, especially the layers 0.10-0.20 m and 0.20-0.30 m. The Bdc decreased with depth for values of 1.68, 1.65 and 1.64 Mg m-3, respectively, in the layers 0-0.10, 0.10-0.20 and 0.20-0.30 m. The management of this soil under integrated crop livestock at a grazing height of 0.10 m had the highest frequency of soil samples with Bd ≥ Bdc.
soil water; Caiuá Sandstone; soil bulk density; water retention curve; soil management; soil quality; resistance to penetration
