Project Overview
Commodities
- Vegetables: cucurbits
Practices
- Pest Management: mulches - living
Proposal abstract:
Western Colorado cucurbit and diversified vegetable producers face severe challenges from escalating hand-weeding labor costs, repeated tillage-induced soil degradation, and weather in semiarid systems. This project innovatively deploys annual living mulches integrated with strip tillage to suppress weeds, protect soil, and boost profitability at two research centers and three on-farm sites.
Problem and Research Questions
Current strategies, i.e., frequent cultivation, plastic mulches, and intensive hand-weeding dominate weed control in Western Colorado cucurbits but demand substantial labor (often the top expense) while eroding soil structure, organic matter, and water-holding capacity on sloping fields. These burdens contribute to statewide payroll strains of 10-12% of gross crop farm income amid chronic shortages (). Therefore, producers and advisors have prioritized reduced-till, continuous-cover systems. The key questions are as follows: (1) How do living mulches affect weed density, biomass, and composition in strip-tilled cucurbits? (2) What changes occur in soil health indicators, including physical, chemical, and biological properties and metabolomic profiles? (3) Does resource competition or allelopathy primarily drive suppression? (4) Do cover cropped systems yield superior economics via enterprise budgets and breakevens compared to standard practices?
Research and Outreach Components
Research implements two-year randomized block trials at WCRC-Rogers Mesa (organic, drip-irrigated), WCRC-Grand Valley (conventional, furrow irrigated), and three on-farm sites (organic/conventional cucurbits), evaluating nine fall-seeded treatments, including live hairy vetch, white clover, creeping red fescue, fescue-clover, and fescue-clover-vetch mixes; terminated versions; and no-cover weeded/weedy controls. Metrics capture weed dynamics (density, biomass, diversity, seedbank), yields, soil health (bulk density, aggregation, respiration, enzyme activity), soil moisture, and canopy cover (RGB imagery); advanced untargeted metabolomics profiles shifts; and greenhouse bioassays dissect mechanisms. Outreach immerses three producer collaborators in trial design/implementation/feedback, hosts annual field days and workshops reaching 200+ growers, co-develops extension materials, and leverages prior SARE models, such as SW11-072, for adoption.
Potential Significance
This delivers incremental advances in weed suppression and soil metrics alongside transformative impacts: substantial reductions in hand-labor demands (e.g., $100-120/acre per weeding pass as in regional vegetable budgets, potentially 1-3 passes/year), 10-20% gains in aggregate stability and enzyme activity, yield increases (e.g., 11% and $50/acre as in SW04-072), moderated moisture/temperatures, and buffered resilience to labor shortages, wage hikes, and droughts. Thus, enhancing SARE's profitability, stewardship, and quality-of-life pillars across Western systems.
Dissemination Strategy
Results reach stakeholders through annual field days (200+ attendees), producer-vetted extension bulletins with plug-in budgets/break-evens, peer-reviewed papers, and meetings, mirroring SW11-072's 210-participant outreach and adoption.
Expected Project Outcomes
Outcomes include the following: (1) Data showing that top mulches suppress weeds by 50% or more while maintaining yields; (2) quantified soil enhancements (e.g., better aggregation and microbial activity); (3) elucidation of weed suppression mechanisms; (4) budgets proving net gains; (5) one PhD Dissertation, three or more publications, and two bulletins; (6) trained graduate and undergraduate students; and (7) five or more farm adoptions impacting hundreds of acres regionally.
Project objectives from proposal:
Research Objectives:
Objective 1. Quantify how living cover crops affect weed density, biomass, and composition in strip-tilled cucurbit fields across two research centers and three farm sites in western Colorado.
Objective 2. Determine how these living cover crop systems affect soil health indicators (physical, chemical, and biological properties, plus soil metabolomic profiles) versus no cover weeded and weedy controls.
Objective 3. Identify key mechanisms of weed suppression (resource competition versus allelopathy) for the best performing living mulch treatment using greenhouse bioassays.
Objective 4. Develop treatment-specific enterprise budgets comparing living mulch systems with standard weed management and share results through field days and extension publications.
Educational Objectives:
Objective 1: Directly engage with regional producers on trial progress and results.
Objective 2: Educate the public, researchers, and agricultural professionals.
Objective 3: Create content for sustained engagement.
Objective 4: Provide professional development opportunities for students and aspiring agriculturalists.