Cover Crop Grazing: Optimal Seasonality for Soil and Livestock Benefit

View the project final report

• 2016 annual report

Commodities

• Agronomic: millet, peas (field, cowpeas), radish (oilseed, daikon, forage), sorghum (milo), wheat
• Animals: sheep

Practices

• Animal Production: feed/forage, grazing management
• Crop Production: cover crops, fallow, no-till
• Education and Training: extension, on-farm/ranch research
• Production Systems: integrated crop and livestock systems
• Soil Management: soil quality/health

Cover cropping has recently been codified in national agricultural policy to enhance soil and protect the environment (NAS 2010). In low rainfall areas of the northern Plains, cover cropping is appropriately aimed at greening the summerfallow period; however it is an economically risky practice, especially in the short run (O’Dea et al., 2013; Miller 2014). Producer feedback and results from a formal survey sent to 450 Montana farmers showed that there is strong interest in grazing cover crops to accomplish soil management goals while providing economic returns in the short run. Further, practitioners of no-till systems are seeking greater diversity in their crop rotations in the form of warm-season crops which are generally poorly adapted for grain yield formation in this region. Research is required to investigate the impacts of integrating livestock in wheat-cover crop systems on soil quality, economic viability, and sustainable food production. This study addresses cover crop seasonality (spring, summer, and winter) and measures biomass production and livestock weight gain in association with various cover crop treatments. In addition, soil quality and nutrient supply parameters will be measured, as will subsequent wheat yield and protein content on cover crops with and without grazing. Experiments will be conducted on two sites as the basis for a M.Sc. graduate student research project (Robert Walker) in high and moderate rainfall areas, on soils with high and low organic matter, respectively. This research will help identify the potential benefits (soil and economic) of crop-livestock integration in dryland wheat systems via the mode of cover crop practice within no-till systems. By making this research and its findings widely available via multiple modes of engagement, producers will be provided valuable information regarding methods of sustainable food production in both soil management and economic contexts, and researchers will likely be presented with new questions. Diverse systems may create more resilient and robust food productions systems and farms that increase economic viability and provide social benefit to local communities and society as a whole.

The purpose of this research is to investigate the effects of integrating livestock grazing into dryland wheat-cover crop systems. The study objectives are:

Soil and Agronomic Objectives

1. 1. To investigate how grazing cover crop mixtures as a termination method affects soil biochemical properties in comparison to using herbicide for crop termination.

1. 1. To assess how changes in soil properties, catalyzed by grazing, affect subsequent wheat yields.
      • • Spring-sown cool-season and summer-sown warm season cover crop mixtures will be terminated chemically and by grazing at an immature stage targeted to conserve soil water. Additionally one warm-season treatment will be left until after soils are frozen and grazed in place.

 Livestock Grazing Objective

3. 3. To evaluate both cool- and warm-season annual cover crop mixtures for potential forage in dryland wheat-cover crop systems.
      • • Weight gains in immature sheep will be measured during three grazing periods (cool-season, warm-season, and early winter) and converted to economic value.

Economic Objective

4. 4. To investigate the marginal net value of annual cover crop mixtures when grazed vs terminated chemically, including their yield and protein effects on subsequent spring wheat
      • • Spring wheat will be grown in the following year at three N fertilizer rates to assess potential economic interactions with cover crop seasonality or termination method.

Educational Implications

5. 5. To increase local producer knowledge of cover crop mixtures and termination methods and potential benefits for soil quality.
      • • We will use pre- and post-presentation mini-surveys to measure changes in local producer knowledge at a field day.

5. 5. To provide local producers with information regarding the potential benefits of ICLS and methods of ICLS adoption in Montana through scientific publications, extension publications, popular press articles, social media, public presentations and research summary, and factsheets.
      • • We will track the number of viewers at each presentation to assess the impact of presentations on producers and others present; use scientific journal impact factor rating to assess the number of researchers impacted by my research; track the circulation and readership of popular press publications to assess the audience impacted by my research; track the number of people who “like”, “follow”, or “view” the information I provide on social media.

The results of this research will help the research and producer communities understand the implications of ICLS systems in comparison to chemical-fallow rotations and rations which include cover crops, but with non-livestock methods of cover crop termination. In a broader sense, this research will further our understanding of the role of livestock and cover crops in sustainable dryland agriculture in Montana. Increasing producer adoption of sustainable practices through research and information dissemination is a vital part of this research project.

Research Timeline: This study will be conducted from the fall of 2015 to the spring of 2017 and will include two growing seasons. During year 1, cover crops are planted and terminated in contrasting treatments using funds provided by other sources from the M.Sc. advisory committee. During year 2, spring wheat is planted, harvested, and analyzed. A second field site will be set-up during year 2 and planted in cover crops with the help of a local producer. This will allow for the continuation of this project and a further examination of cover crops and ICLS in a more arid environment. Research papers from this study will be submitted for publication during the fall of 2016 and spring of 2017. A Master’s thesis covering this research will be produced and defended no later than the spring of 2017 after two cover crop years and one wheat test crop year. The final wheat test crop will be harvested, analyzed, and reported under Perry Miller’s direction using other funding sources.