Submitted to: World Congress of Soil Science
Publication Type: Proceedings
Publication Acceptance Date: 12/6/2001
Publication Date: 12/6/2001
Citation: STOTT, D.E., GREEN, V.S. SOIL BIOCHEMICAL AND STRUCTURAL CHARACTERISTICS IN NATIVE AND TILLED BRAZILIAN CERRADO SOILS. CD-ROM. BANGKOK, THAILAND: WORLD CONGRESS OF SOIL SCIENCE. 2001. Interpretive Summary:
Technical Abstract: Brazilian Cerrado is undergoing rapid capital-intensive agricultural development. Soil quality in the Cerrado region is a pressing issue due to low fertility of these soils. There is limited knowledge on the baseline soil quality of these soils under native vegetation, with regards to the biochemical properties, and how the parameters shift under agricultural management. Soil enzymes are involved in nutrient cycling processes and are indicative of the general biological activity of the soil. Enzyme activities are sensitive to soil management and show signs of soil degradation before other physical and chemical indicators. Our objective was to determine the impact of different tillage practices on soil biochemical properties. The soil used was a dark red latosol. We hypothesized that soils managed with tillage systems would have lower biological activity than soils under native vegetation, and among managed soils, no-till soils would have the highest biological activity and organic C content. Analyses indicate that as organic C decreased under tillage, biochemical activity decreased. When managed, the no- till soils maintained the highest activities, followed by the disk harrow system having lower activities. These results indicate that tillage regimes that are less aggressive maintain higher biological activity in these tropical Cerrado soils. Soil organic carbon levels followed the same pattern as the enzymatic activities. The increase in biological activity and organic C translated into an increased aggregate stability. In these tropical soils, a no-till management system is likely to be more sustainable due to the influence of soil biological activity in nutrient cycling and aggregate stabilization.