ABSTRACT
An evaluation was made of the physical quality of a sand-clay Red-Yellow Latosol loam in the semi-arid region, cultivated under no-tillage (SPD) and conventional tillage (SPC) systems under different soil cover. The experiment was set up in a single plot (18 x 18 m) for each of the six treatments: two cropping systems and three crops (maize, sunflower and sorghum) planted in the summer, ahead of the beans sown in the autumn/winter, with the native forest (MN) as control. Litter on the soil surface, soil penetration resistance, total organic carbon, aggregate stability in water, soil bulk density, macropores, micropores, total porosity and water retention were evaluated at depths of 0.00 to 0.05, 0.05 to 0.10, 0.10 to 0.20 and 0.20 to 0.40 m. The best physical indicators of soil quality under semi-arid conditions were found in the soil under no-tillage and grass. No-tillage keeps soil aggregation at a level similar to that of MN, whereas under conventional tillage, aggregation and carbon input are reduced in the soil. Grasses under no-tillage increase the carbon content of the soil, due to a greater production of litter compared to the sunflower. No-tillage causes greater surface soil compaction than conventional tillage but has no effect on water retention. The treatments had no effect on any of the attributes at the depth of 0.20 to 0.40 m.
Key words:
Aggregation; Porosity; Soil density; Organic carbon
