Effects of Tillage, Rotation, and Organic Inputs on Soil Ecological Properties in Vegetable Crop Production Systems
Agricultural management decisions that influence biological activity and diversity include tillage, fertilizer and pest-control inputs, cover crops, and crop rotations. Our objective was to characterize relationships between biological and physical properties resulting from long-term agricultural management decisions. This research employed a factorially-designed field experiment to examine the effects of tillage (moldboard plow or strip-tillage), input (synthetic fertilizers and pesticides or organic inputs), and crop rotation (continuous staked tomatoes or 3-year vegetable rotation) on a suite of biological and physical soil parameters. Biological measurements were generally responsive to all treatment combinations, but tillage provided the strongest treatment effect in most cases. Tillage consistently yielded significantly lower values compared to strip-tillage for the following biological measurements: total C and N, above-ground biomass, microbial biomass, enzyme activity, soil respiration, N mineralization, and earthworms. Synthetic inputs consistently induced significantly lower values compared to organic for the following biological measurements: microbial biomass, enzyme activity, some nematode trophic groups, and soil respiration. We examined relationships between biological and physical soil properties using redundancy analysis. Of the physical properties measured, microporosity was the best predictor variable for most biological parameters. We conclude that soil organisms responded to the implemented treatments in the following order: tillage > input > rotation.
PhD Graduate Student
Dept. of Soil Science, NCSU
Raleigh, NC 27695-7619
Office Phone: 9195133037