Combining Strip-Tillage and Cover Crops for Resource Conservation and Profit in North Central Vegetable Cropping Systems

Combining Strip-Tillage and Cover Crops for Resource Conservation and Profit in North Central Vegetable Cropping Systems

Summary

Our work in 2013 included both on-farm trials and continuation of a long-term research farm trial investigating the impact of tillage (strip tillage [ST] vs conventional tillage [CT]) cover crops (none, rye or rye-vetch) and weed management intensity (low vs high) in snap beans and sweet corn. These treatments have been repeated in the same location in two separate adjacent field trials through a three-year sequence of sweet corn/snap beans/winter squash since 2009 (Field 1) or 2010 (Field 2). For both snap beans and sweet corn grown in 2013, ST produced equivalent or higher yields at lower cost than CT. ST in combination with either rye or rye-vetch cover crops also improved soil moisture retention under hot dry conditions. After 5 years we have observed a gradual increase in large crabgrass and horsenettle populations under ST. In the absence of winter cover crops, winter annual weeds have also become more prevalent under ST. However, with winter cover crops, winter annuals populations under ST have been equivalent to CT. Outputs from our work in 2013 included newsletter and journal articles, and presentations at grower meetings and conferences. Outcomes in 2013 included increased understanding among vegetable growers of the potential benefits of reduced tillage and identification of complementary weed and cover crop management practices for reduced tillage production.  

Objectives/Performance Targets

The central objectives of our proposed work in 2013 were1) to evaluate the interactive effects of strip-tillage, cover crops, and weed management intensity within vegetable cropping systems on soil health, pest population dynamics, and crop quality and yield; and 2) to work with growers and extension educators to disseminate useful information and identify and address constraints to adoption of reduced tillage production systems.

Accomplishments/Milestones

Research activities included 1) research farm experiment evaluating the long-term effects of tillage and cover crops on sustainability of vegetable cropping systems; 2) on-farm experiments identifying and evaluating complementary weed and cover crop practices for reduced tillage vegetable production systems.

 Long-term trial. Rotational crops in the long-term experiment in 2013 included sweet corn and snap beans. The trial is evaluating the effects of tillage (strip tillage [ST] vs conventional tillage [CT]) cover crops (none, rye or rye-vetch) and weed management intensity (low vs high) in a sweet corn/snap bean/winter squash rotation initiated in 2009 and 2010 in two adjacent fields (Figure 1). For snap beans in 2013, ST produced equivalent yields at lower cost than CT (Figure 2). Snap bean yields also appeared to improve under rye-vetch relative to bare soil (p=0.07). This cover crop effect may have been due in part to reduced prevalence of common lambsquarters where winter cover crops were present, especially in the between row zone of ST (Fig. 3). For sweet corn in 2013 (Field 2), yields appeared to be improved under ST compared to CT, but only under high weed management intensity (Fig. 4). Improvements in sweet corn growth under ST were evident just before topdressing in late June, when CT sweet corn appeared chlorotic and stunted relative to ST; dry weight of sweet corn in CT at that time was lower than ST, regardless of cover crop treatment (Fig. 5). Weed seedbank analysis in 2013 revealed higher densities of large crabgrass seeds in ST compared to CT and in low-weed management compared to high weed management treatments (Fig. 6). In the absence of winter cover crops, winter annual weeds—including henbit, purple deadnettle and chickweed—have become more prevalent under ST; however, with either winter rye or rye-vetch mixtures, winter annual densities were equivalent to CT (Fig. 7). Under ST, we have observed a gradual increase in the abundance of the perennial weed horsenettle (Fig. 8), which may require additional herbicide applications in the next few years to avoid yield losses.

 On-farm trials and surveys. On-farm trials in 2013 included one trial evaluating the effects of tillage (ST vs CT) and cover crops (spring oats vs none) on sweet corn yields on a commercial vegetable farm. A second trial planned to evaluate strip tillage for pumpkin production was abandoned after excessive flooding in the spring prevented timely planting. In the sweet corn trial, no differences in yields were detected between ST and CT treatments. In addition to research trials, we have continued interviews with sweet corn farmers on their production practices and attitudes towards reduced tillage. We are updating the sweet corn cost of production bulletin for Michigan, and will use economic data generated from this process to better assess the impact of tillage and cover crop practices on farm profits. In addition we initiated a written survey sent to over 300 organic field and vegetable growers to evaluate their attitudes towards reduced tillage and to better understand constraints to adoption. So far we have received over 80 responses and plan to begin analyzing these during 2014.

Impacts and Contributions/Outcomes

Short-term outcomes

1)    Increased understanding of the potential benefits of ST systems for improving soil health and reducing energy and labor costs: In 2013 we observed improvements in soil moisture retention under strip tillage, reductions in energy costs, and equivalent or higher yields in both snap beans and sweet corn. In sweet corn we saw benefits of ST for early growth, due perhaps to better retention of sulfur (under investigation).  

2)    Identification of complementary weed management practices to optimize strip-tillage systems: In 2013, we identified the need for greater attention to weed management practices to address potential problems from build-up of large crabgrass and horseweed under ST. We also saw benefits of cover crops for suppression of winter annual weeds and common lambsquarters.

3)    Increased understanding of optimal cover crop practices for strip-tillage systems: In 2013, we observed benefits of both rye and rye-vetch cover crop residues for reducing weed problems and improving weed suppression under ST. In the case of snap beans, rye-vetch cover crops appeared to provide a yield benefit.

4)    Increased awareness of the circumstances under which reduced tillage systems are most/least likely to be beneficial due to changes in insect, disease and weed dynamics: In 2013, we saw no major impact of tillage or cover crops on insect or disease pests in sweet corn or snap bean. In some previous years we have seen reductions in potato leaf-hopper in snap beans under ST.

5)    Greater grower understanding and interest in reduced tillage systems for vegetable crops: We have seen strong interest in ST systems, both in sweet corn and winter squash.

Outputs

Peer-reviewed Publications

1. Brainard, D.C., E. Haramoto, M.M. Williams and S.B. Mirsky. 2013. Towards a no-till no-spray future? Introduction to the symposium on non-chemical weed management in reduced tillage cropping systems. Weed Technology 27: 190-192.
2. Brainard, D.C., E. Peachey, E. Haramoto, J. Luna and A. Rangarajan. 2013. Weed ecology and management under strip-tillage:  Implications for Northern U.S. vegetable cropping systems. Weed Technology 27: 218-230.
3. Bryant, A., D.C. Brainard, E. Haramoto and Z. Szendrei. 2013. Cover crop mulch and weed management influence arthropod communities in strip-tilled cabbage (Brassica oleracea). Environmental Entomology 42: 293-306.

Presentations at Grower Conferences

1. Brainard, D.C. 2013. Protecting soils and boosting profits with strip tillage and cover crops. Soil Health Session. Great Lakes Fruit, Vegetable, and Farm Market Expo, Grand Rapids, MI, December.
2. Brainard, D.C. 2013. Cover crop research and your bottom line. Making Sense with Cover Crops Workshop. Midwest Cover Crop Council Annual Meeting. London, Ontario, Canada. Feb 28.
3. Brainard, D.C. 2013. Reduced tillage and cover crops in vegetables. Midwest Cover Crop Council Annual Meeting. London, Ontario, Canada. Feb 28.
4. Brainard, D.C. 2013. Weed ecology and management in vegetable cropping systems. Integrated Pest Management Session. Great Plains Grower Conference. St. Joseph, MO. Jan 11.
5. Brainard, D.C. 2013. Benefits and limitations of cover crops in vegetable production. Illinois Specialty Crops, Agritourism, and Organics Conference. St. Louis, MO. Jan 9.
6. Brainard, D.C. 2013. Using cover crop residues and reduced tillage to protect soil and reduce energy costs in sweet corn production. Illinois Specialty Crops, Agritourism, and Organics Conference. St. Louis, MO. Jan 9.

Other Extension Presentations

1. Brainard, D.C. 2013. Overview of long-term reduced-tillage field study. MSU Vegetable Extension Group Summer Tour. South West Michigan Research and Extension Center, Benton Harbor, MI. August 5.
2. Brainard, D. C. 2013.Reduced tillage strategies for sweet corn and hard squash. Ag. Consultants Breakfast. Hart, MI, June 20.
3. Hayden, Z.D., Ngouajio, M., and D.C. Brainard. 2013. Cover Crops, Strip-Tillage, and Nitrogen Management. Oceana County Soil Management Extension Workshop, Shelby, MI. 20 March.

• Figures

Collaborators: