This project investigated no-till spring vegetable production after low-residue winterkilled cover crops, primarily forage radish (Raphanus sativus L.), throughout the northeast. Experiment station research at two contrasting sites in Maryland, Clarksville and Wye, during 2011-12 and 2012-13, one year of on-farm experiments in Maine, 12 small on-farm trials in Maryland, Pennsylvania, and New Jersey, and one experiment station trial in Massachusetts revealed that differences in fall cover crop performance and soil conditions lead to variable results from no-till seeding spring vegetables after forage radish. Successful no-till seeding in spring requires early fall cover crop seeding, rapid growth, and early canopy closure to ensure spring weed suppression. Additionally, soil conditions in spring must not hinder water movement, gas exchange, seed emergence, and root growth. Poorly aggregated and/or easily compacted soils appear not to support no-till seeded vegetable crop growth.
Results from Clarksville showed no-till spinach yields after forage radish as high as 17,000 lb/acre. No-till spinach yields were equal or greater than the yields in tilled seedbeds both years at Clarksville. In contrast, tilling in a radish cover crop increased spinach yield more than 60% compared to the no-till spinach at Wye, though the differences were significant only in 2013. Limited trials with lettuce and kohlrabi indicated that while emergence was equal or greater in no-till plots, maturity was delayed. In on-farm experiments in a sandy soil in Maine, no-till seeded carrots after forage radish matured at an equal rate to those in tilled seedbeds and were of higher marketability, but one farmer in Maryland with silt loam soils reported poor root development in no-till seeded carrots. Five of the collaborating farmers reported that they have incorporated the forage radish no-till system into their regular practices for spring crops including spinach, peas, beets, onions, and carrots, whereas five expressed concerns that dissuaded them from no-till seeding after forage radish, or using forage radish as a cover crop at all. These concerns include the possibility of disease or pest carry-over into other brassica cash crops, the early seeding date required for optimal forage radish performance, and the poor performance of no-till seeded crops in their soils.
During this project, we have given presentations to over 1500 individuals at over 20 meetings and field days throughout the northeast and at international meetings, had over 40,000 unique visitors to our website and blog devoted to cover crop-based reduced tillage vegetable production, had over 2700 YouTube video views, had bulletins and articles in outlets with circulation totaling over 40,000, and have had one peer-reviewed journal article published and another in review.
- 120 farmers growing 2,400 acres of spring-planted vegetables will use forage radish and/or other winterkilled cover crop no-till planting system for half their spring acreage. They will reduce fall/winter N leaching by 100lbs/acre (total reduction of 120,000 lbs of N) and will use 50 lbs/acre less N fertilizer (saving >$400/acre for organic growers) in spring (60,000 lbs less N fertilizer used per year). They will use no primary spring tillage and no burndown herbicide on these acres resulting in 3 tons less erosion per acre (36,000 tons less erosion) and 1,000 lbs less herbicide sprayed. On average, they will plant their crops 10 days earlier and harvest 7 days earlier than with their old system; they will save $100/acre seedbed preparation costs ($120,000 per year) and earn $500/acre ($600,000 total) more in crop sales per year.
- 12 vegetable farmers in Maryland, Pennsylvania and New Jersey will collaborate in this research by putting out replicated strips on their farms comparing forage radish no-till planting with their customary practice for early spring vegetable planting (August 2011-May 2012).
- 6 of these farmers will experiment with other winterkilled cover crops or mixtures of forage radish and other cover crops (August 2012-May 2013).
While it is impossible for us to assess the extent of adoption of this system and the savings it has incurred, we collaborated with 12 farmers in Maryland, Pennsylvania, New Jersey, and Maine who all tried no-till seeding their spring crops after forage radish. Our original targets did not include New England farmers, but because of personnel involved on this project, we were able to extend the region for research and outreach activities beyond the mid-Atlantic. The “success” rate of these trials was about 50%. Our research documented that radish increases spring soil inorganic N content, and translating this increased N into reduced fertilizer recommendations requires further documentation. Despite interest in mixtures, fewer farmers were interested in trying them and those who did had less success with weed suppression, making them unfavorable for no-till seeding without herbicides.