Reduced-Tillage Weed Management for Organic Farming
Sustainable Agricultural Systems Laboratory
2011 Annual Report
1a.Objectives (from AD-416)
Develop improved agronomic approaches for terminating cover crops, establishing crops, and suppressing weeds in reduced-tillage, high residue organic farming systems. Evaluate the performance of minimum-tillage organic systems in the long-term Farming Systems Trial.
1b.Approach (from AD-416)
Component experiments will be conducted by the Coooperator to investigate the following factors for improving and increasing the consistency of reduced-tillage organic systems. First, cover crop mixtures at selected ratios will be assessed for facilitation of cover crop kill, ease of planting and crop establishment, and weed suppression. Second, the timing of planting relative to cover crop kill will be assessed for interactions with the cover crop mixture factor. Third, the spatial distribution of cover crop species relative to planting patterns will be explored. Fourth, rescue cultivation approaches will be evaluated that effectively control weeds with minimum soil and residue disturbance. The long-term Cooperator's Farming Systems Trial (FST) provides a unique opportunity to determine the long-term effects of tillage in organic systems and how they compare to the well-known effects of tillage in conventional systems. The FST has recently been redesigned to include a tillage split (plow tillage versus reduced-tillage) within both the organic and conventional systems. We propose to enhance the capability of the Cooperator to collect data during the next five years at FST in order to more comprehensively determine weed population dynamics and crop performance in these systems. In addition, influences on soil quality and how these changes indirectly affect weed and crop responses to tillage will be determined. This information will be used by both ARS and the Cooperator to develop peer-reviewed publications as well as recommendations for improved no-tillage organic systems that can be distributed through field days, web-sites, and other appropriate technology transfer channels.
Reducing tillage frequency in organic soybean production requires optimal soybean establishment and supplemental control for perennial weeds. A second year of two field trials was conducted by collaborators at Rodale Institute. The first experiment evaluated planter coulter and trash wheel configurations to improve no-till planting of soybeans into a rye mulch. A soybean crop was planted at rolling or at 7-10 days after rolling and at rye anthesis or soft dough stage to evaluate the influence of rye residue quality on establishment. The second experiment evaluated the frequency and timing of high-residue cultivation on weed-crop competition in a cover crop-based rotational organic no-tillage soybean crop. Coordination of field projects were completed through project meetings and updates throughout the year including two at Rodale Institute. In addition, planning sessions via teleconference calls and emails were conducted with collaborators to address implementation and protocol.