Low-input Reduced Tillage Crop Production Systems for the Southern United States

Low-input Reduced Tillage Crop Production Systems for the Southern United States

Summary

Reduced tillage potentially can play a key role in sustainable agriculture production systems by reducing soil erosion, decreasing fossil fuel use, decreasing weed pressure through maintenance of surface mulch, and enhancing soil productivity through crop residue and organic matter maintenance. Reduced tillage technologies have not been incorporated into low-input cropping systems. The overall thrust of this project is to develop low-input wheat/soybean/corn production systems which incorporate reduced tillage technologies.

Project Results

Low-input reduced tillage crop production systems can potentially play a key role in sustainable agriculture systems by reducing soil erosion, decreasing fossil fuel use, decreasing weed pressure through maintenance of a surface mulch, and enhancing soil productivity through crop residue and soil organic matter maintenance. The overall objective of this project was to develop low-input reduced tillage crop production strategies appropriate for use in the Southern United States.

Results from this study indicate that low-input reduced tillage technologies can be profitably implemented in the Southern United States under certain conditions. Namely, the intermediate mix of inputs (intermediate N fertilizer in combination with a cover crop, intermediate herbicide use and no-tillage) resulted in yields that were comparable to those obtained using a high (currently recommended) mix of inputs (high N fertilizer, high herbicide use and conventional tillage). Additionally, soil conservation benefits associated with no-tillage and legume cover cropping practices included increased water infiltration, increases in soil organic matter content, and increases in soil organic matter content, and increases in soil microbial activity. Additional findings included: 1) tillage and herbicide use patterns can be modified without greatly affecting foliage-inhabiting arthropod populations in soybeans, 2) the negative effects of shading associated with intercropping soybeans into wheat does not result in yield reductions when the period of overlapping crops is relatively short, 3) reduced herbicide use (postemergence application only) can be adopted in intermediate tillage regimes without significantly reducing yield of soybeans or corn, but results in yield reductions under no-tillage conditions, as compared to high (pre- and postemergence application) herbicide applications, and 4) weed management for intercropping systems may require little or no herbicides if intensive crop management, crop rotation, and crop scouting are practiced.

All of these results were presented at professional meetings, and published in scientific journals and the popular press. Demonstration plots were initiated at six locations in agricultural regions in Georgia and South Carolina. Cumulative attendance at field days exceeded 1000 farmers and other clientele. Four farmers are involved in on-farm demonstrations of interseeding techniques, and one farmer has adopted interseeding technology in his commercial operation. Results were presented in farm journals and other non-scholarly publications to inform farmers of the potential of low-input reduced tillage crop production systems and interseeding technologies.

This study indicates that there are many combinations of factor levels that can produce acceptable yields for crop rotations in the Southern United States. However, the primary requirement for the success of low-input reduced tillage systems is that they must be flexible to account for variations in environmental conditions, and that they must employ various combinations of input factors that are suitable for prevailing conditions. In conclusion, the yield results obtained in this study indicate that tillage, herbicide, and N fertilizer applications by prescription are an anathema to successful sustainable agriculture systems.

Objectives

(1) Evaluate combinations of three levels of three important factors in sustainable, low-input production systems, namely tillage, nitrogen fertilizer, and herbicides.

(2) Determine the profitability of the systems evaluated in the field.

(3) Demonstrate profitable low-input, reduced tillage production systems on a field-scale.

(4) Optimize relay intercropping technologies, including weed management.

(5) Evaluate crop rotation benefits with respect to pest management and control.

(6) Evaluate legume germ plasm for use as nitrogen-supplying cover crops.