Comparison of Reduced Tillage Practices for Small-Scale Organic Vegetable Production.

Small, diversified organic vegetable farms (<10 acres) need reduced tillage (RT) practices that work across a range of crops. These growers may effectively reduce tillage and soil compaction by dividing fields into permanent beds that restrict traffic to between-bed areas year after year. We are evaluating the agronomics and economics of RT practices for permanent beds in Freeville, NY and Monmouth, ME, over four years. Cabbage (yr 1) and winter squash (yr 2) were managed with four levels of tillage intensity, from high (deep rototilling) to low (no-till) soil disturbance. We compared two no-till systems, one with a tarp placed on the soil surface for at least six weeks prior to planting. Tarps were impermeable, durable black plastic used to suppress weeds between crops. Within each tillage system, we compared straw mulch to bare soil and measured changes in soil microclimate, weeds, time spent in all field operations, and crop quality and yield. Straw mulch lowered yields in NY in both years, where pest pressure decreased plant growth and stands, but not in ME. Shallow surface tillage (<10 cm) gave similar results to deep tillage (20 cm) at both locations, regardless of mulch. In both years, tarping improved the performance of no-till production, especially for bare soils. Tarps created weed-free planting conditions without soil disturbance and reduced labor for hand weeding by over 70% (yr 1) and 80% (yr 2) when compared to no-till without tarps. Spring soil temperatures increased under tarps and when removed, plant-available soil nitrogen in bare, tarped soil was over four times greater than tilled soils (yr2). Crop yields with no-till tarping were similar to or greater than the tilled systems. Tarping may be a valuable tool for small-scale organic farmers to reduce tillage while improving planting conditions, weed control and crop productivity.