Relationships between soil biological and chemical characteristics and surface soil structural properties for use in soil quality

Mateugue Diack, Purdue University

Abstract

While there are many long-term management studies on soil productivity and pest management, few have looked at the long-term effects on surface soil structure and how changes are related to the soil biology and biochemistry. This study was conducted on a 16-year integrated pest management field where several tillage and crop rotation combinations were available. Sealing index, as a measure of soil aggregate stability, decreased with decreasing tillage intensity. However, final infiltration rate was highest in chisel plow system. Total organic C and N, microbial biomass C, soil carbohydrates and soil enzyme activities were significantly greater in conservation systems as compared to conventional practices. A simple and sensitive method of optimizing fluorescein diacetate hydrolysis was developed and used in these soils. This enzymatic activity is involved in lipid metabolism which is ubiquitous to all living cells. Bulk density was negatively correlated with soil enzyme activity. Tillage appeared to play a major role in the soil property changes with crop rotation system differences being minor. Using soil erodibility as the baseline, a set of soil quality indicators was developed. For soil quality rating, a standard scoring function was developed, and the three management systems were rated from the lowest to the highest: moldboard plow ∼ no-till < chisel plow due to the unusual nature of this no-till field. Results suggest that soil biochemical and biological properties are potential indicators of soil quality with regard to soil erodibility.

Degree

Ph.D.

Advisors

Stott, Purdue University.

Subject Area

Agronomy|Soil sciences

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