Cardboard layering deep compost mulch for weed suppression, soil health, and profitability

View the project final report

Commodities

• Vegetables: greens (leafy)

Practices

• Crop Production: no-till
• Education and Training: on-farm/ranch research
• Soil Management: soil quality/health

Weed pressure is a particular issue at Sweet Hollow Farm. Perennial bindweed is abundant across the farm due to its ability to spread by seed and through its vigorous rhizomes. In previous seasons, weed management consisted of spring-time tillage followed by intensive weeding throughout the growing season. Alongside the prohibitive time demand of this approach, the producers understand the harmful effects of continuous tillage to soil health and desire an alternative bindweed management strategy. Based on preliminary attempts at our farm and at a partnering farm, Foraging Farms, a cardboard layer deep compost mulch system (CLDCM) has shown potential against perennial bindweed. Qualitative assessment of the soil beneath the cardboard layer in these beds also shows worm activity, aggregate formation and moisture retention - indicators for healthy soil. Through this grant and in partnership with the University of Wyoming, we wish to answer the following research question: Can a cardboard layering and deep compost system (CLDCM) be used to reduce bindweed pressure while encouraging productive soil health and crop yield?  If successful, the CLDCM method will have significance for small-scale producers by showing that aggressive weed pressure can be managed without tillage while simultaneously building up soil health and farm profitability. *Bindweed photo in additional documents.

Results of the study will be shared with local and regional agricultural stakeholders through on-farm workshops, field days, and demonstrations. We will create informative pamphlets for other farmers to be distributed though the University of Idaho extension and the Teton Food and Farm Coalition.

The project objectives include: 

1. Weed suppression: Identify whether there is a quantifiable difference in bindweed presence in the cardboard layering and deep compost mulch (CLDCM) strategy compared to our current weed management system that relies on tillage and frequent manual weeding. Reducing weed pressure lessens labor hours for the farm, lowering costs and improving the quality of life for the farmers. Lower costs in turn increases profits for the farm. 
2. Improving Soil Health: Soil samples will be collected at the beginning and end of the study period in the test and control produce beds. The soil samples will be analyzed for chemical, physical, and biological soil health indicators at the University of Wyoming. Comparing results will show if soil health is improving in the cardboard layering and deep compost system compared to our standard tilling practice. Soil health results from Sweet Hollow Farm will also be compared with soil samples from partnering farm, Foraging Farm, which has used the same CLDCM methods since it began five years ago. 
3. Profitability: Differences in productivity will be quantified by harvested produce weights of kale crops. The crop harvest will be weighed upon collection for each test and control plot. Each week the test block and control block will be weeded, timed, and total hours required will be recorded.
4. Education: Producers will host and lead various education and outreach programs to share their findings, but also encourage a new wave of small scale farmers. Activities will include workshops, field days, demonstrations, informational pamphlets, and a podcast recording.