Hydrophysical Quality of an Oxisol Under a No-tillage System with Alternative Crops to Renew a Sugarcane Field

Abstract

Maintaining crop residues on the surface of soils with the possibility of renewing sugarcane fields could be a key factor for improving the structural quality of the soil. The objective of the present study was to assess the structural quality of soil after the use of alternative crops under a no-tillage system in the restoration of a sugarcane field, by the least-limiting water range (LLWR) and the load-bearing capacity (LBC) models. The study utilized a randomized block design in a banded scheme, with six treatments and five replications. Two soil depths were evaluated: 0.15 and 0.25 m. The five crops studied were Crotalaria juncea, C. ochroleuca, Helianthus annuus (sunflower), Glycine max (L.) Merrill (soybean), and Sorghum bicolor (L.) Moench (sorghum), in addition to a fallow treatment. The highest LBC values in the 0.15 m depth were provided by the treatment grouping of soybean–sorghum until the water content reached 0.26 m3 m−3; after this value, the highest LBC values were provided by the C. ochroleuca–C. juncea–sunflower–soybean treatment grouping. In the 0.25 m depth, the highest LBC values were provided by the C. juncea–sunflower–sorghum treatment grouping until the water content reached 0.26 m3 m−3; after this value, the highest LBC values were provided by the fallow–soybean grouping for water content reaching 0.50 m3 m−3. The crops used prior to sugarcane planting modified the physical and water properties of the soil at the two depths evaluated.