'Squashing' the Nutrient Competition: Optimizing Fertility and Weed Management for Profitable Low-Till Organics

Commodities

• Vegetables: cucurbits

Practices

• Crop Production: no-till, nutrient management, water management, zone till
• Production Systems: organic agriculture

The long term soil health benefits of cover crop-based no-till and low-till are well established, and conventional herbicide-based no-till systems for squash and pumpkins are expanding nationally. Of particular interest for our region, reduced tillage systems offer significant benefits for managing soil moisture and erosion. However, best practices for organic growers, especially as regards managing weed pressure and soil fertility, are still in need of research and experimentation.

This project will conduct side-by-side trials of two organic, reduced tillage vegetable systems for winter squash production. These trials will (1) refine best practices for and (2) to evaluate the relative profitability of Organic cover-crop-based reduced tillage as compared to plasticulture. Centering our research on the financial bottomline will enable us to answer small and medium-scale growers' crucial questions about the risks and rewards of no-till, especially given relatively high specialty equipment costs.

Over two years, we will compare (1) our own organic Deep Zone Tillage system (DZT), (2) a cover crop-based no-till soil occultation system, and (3) an organic plasticulture control. We will compare these systems' relative profitability and identify the optimal fertility regimen for cover-crop based reduced till (CCBRT) production. In addition to comparing yields, we will track and compare production costs, labor costs, and differences in soil moisture and plant health to create a holistic picture of practice profitability. We will share our results with an on-farm equipment demonstration, a conference presentation, and a webinar disseminated online through a regional farming non-profit.

We are proposing side-by-side trials of these three systems, with data collection on yields, cost of production, crop health, and soil moisture to help answer the following novel research questions:

• Can we "fertilize our way out of" the nutrient challenges in mid-scale, cover crop-based reduced tillage systems? With additional inputs throughout the season can Deep Zone Till approach the yields of plasticulture and tarping?
• How do high temperatures and in-season rainfall quantity and intensity affect yields in these systems?
• When each system is optimized, which is the most profitable when evaluating yield, marketability, and cost of production?
• Can we model effective enough mid-scale reduced tillage systems to encourage other farmers to adopt and experiment with them on their own farms?

We will do so via the following goals:

1. Evaluate the relative profitability of two cover-crop based reduced tillage systems for winter squash production by conducting side-by-side trials, in two replications per year, over two years. Systems:
   • Cover crop-based Deep Zone Tillage (DZT)
   • Cover crop-based soil occultation ("Cover Crop-Tarp-No-Till" or CCTNT), as outlined in SARE project LNE18-371R and related UME-published guide
   • Plasticulture control
   • For each system, we will use two bush-type squash varieties: Atlas F1 butternut (an industry standard for wholesale) and Tiptop PMR (specialty acorn important for CSA and market garden operations)
2. Identify optimal fertigation regimens for the above reduced till systems.
   • All treatments will receive the Mid-Atlantic Commercial Vegetable Production Recommendations based on soil tests
   • Half of beds also receive an additional 66% of recommended nitrogen pre-plant, at planting, and sidedressed via fertigation. Attempting to "over"-fertilize to overcome nutrient tie-up from cover crop residues
   • Send two mid-season plant tissue samples (one three weeks after transplanting, and one after sidedressing when vines "run") from all treatments and compare nutrient data
   • Compare per-plant yields from random sections of each treatment
3. For all varieties and treatments above we will track the following:
   • Yields
   • Supplies costs, including single use materials (eg, plastic mulch) and pro-rated reusable materials (eg, silage tarps)
   • Tractor and labor time in: Field prep; Planting; Weed, pest, and disease management; Harvest; Post-harvest (eg, mulch and tarp removal)
   • Collate above tracked data over the two years to compare the relative profitability of each cropping system
4. Track impact of tillage treatments on soil moisture throughout season
   • Install soil tensiometers in each treatment in each plot
   • Track soil moisture weekly and rainfall as relevant throughout the season.
5. Conduct outreach based on our results in the following ways
   • Conduct an on-farm Equipment Demonstration for DZT and CCTNT approaches in Spring 2027, at which we will share preliminary results from the 2026 season. Demo will be promoted by Future Harvest.
   • Apply to present final results of the experiment at two regional conferences.
   • Record a podcast/ webinar with Future Harvest to be disseminated online.