Integrating Perennial Living Mulches into Irrigated Cropping Systems

View the project final report

• 2009 annual report
• 2010 annual report

Commodities

• Agronomic: corn, oats, grass (misc. perennial), hay

Practices

• Animal Production: stockpiled forages, winter forage, feed/forage
• Crop Production: conservation tillage
• Education and Training: demonstration, extension, on-farm/ranch research
• Farm Business Management: budgets/cost and returns
• Pest Management: mulches - living
• Production Systems: agroecosystems
• Soil Management: organic matter, soil quality/health
• Sustainable Communities: sustainability measures

Soil erosion and the high cost of fuel and fertilizers are critical issues that threaten the sustainability of agricultural systems. Integrating “living mulches” with irrigated crop production practices can potentially offset these environmental and economic issues. Living mulches consist of perennial plants that are used as cover crops in the production of annual cash crops. Much in the same way as annual cover crops, living mulches can decrease soil erosion, suppress weeds and insects, improve soil structure and nutrient cycling, sequester carbon, protect seedlings of other crops during establishment, and supply nutrients to the associated crop, especially nitrogen when using legumes. A major advantage of perennial living mulches is that they provide soil cover all year since they do not have the regular establishment periods required for annual cover crops. The benefits of living mulch systems have been proven in the upper Midwest and Northeast under rain-fed conditions, but have not been tested in the semi-arid West. The ability to control the timing and amount of water applied in an irrigated environment should improve the success of this type of system. The objectives of this project are to: 1) determine methods of establishing various perennial plant species potentially adapted for use as living mulches under irrigation, 2) evaluate methods of suppressing living mulches that both conventional and organic producers can use to avoid reduced yields of associated crops, 3) quantify the environmental and economic benefits of using living mulch systems under irrigation, and 4) demonstrate the benefits of using living mulch systems for crop production under irrigation to producers through on-farm trials. This project will be conducted at two of Colorado State University’s research facilities and two on-farm producer sites. These sites represent diverse environments within Colorado that will have direct application for producers in surrounding states. Plot studies will be used to evaluate potential species for use as living mulches including alfalfa, birdsfoot trefoil, red, white, and kura clover, and crownvetch. Only legumes will be investigated because of their nitrogen fixing capability. Species evaluated will be seeded alone, in mixtures, or with cover crops such as small grains and corn. Several rates of starter nitrogen will be evaluated as a method of improving establishment. Broadcast and band applications of herbicides and strip tillage will be evaluated in conventional and mowing, flaming, and strip tillage in organic cropping systems as methods of suppressing the living mulch to avoid yield reductions of associated crops. Nitrogen replacement values will be determined by comparing yields from conventionally fertilized and living mulch plots. Besides crop yields, return flow water quality will be monitored along with yield and quality of the living mulch and any crop aftermath that could be utilized as forage. Information from this project will be disseminated at field days, via newsletters, extension fact sheets, technical reports, and web sites, and at producer oriented seminars and workshops. Additionally, two scientific articles will be prepared and published in Agronomy Journal. Producers will initially gain awareness of the living mulch concept and then learn how to integrate these systems with their irrigated crop production practices through our outreach activities. By learning of the potential economic and environmental benefits associated with living mulch systems, producers will be moved to adopt this technology on their farm. This project involves the direct participation of two innovative producers who represent diverse areas of Colorado. One is a conventional producer while the other produces organic crops. This project will be evaluated using survey forms filled out by participants who attend field days, tours, and formal technology transfer meetings. Participants will evaluate their understanding of the potential environmental and economic benefits of living mulch systems, any potential barriers to adoption, and number of acres implemented.

• 1. Determine methods of establishing various perennial plant species potentially adapted for use as living mulches under irrigation.2. Evaluate methods of suppressing living mulches that both conventional and organic producers can use to avoid reduced yields of associated crops. 3. Quantify the environmental and economic benefits of using living mulch systems under irrigation. 4. Demonstrate the benefits of using living mulch systems for crop production under irrigation to producers through on-farm trials.