- Vegetables: multiple vegetable crops
- Soil Management: nutrient mineralization
Years of research on nitrogen contributions from cover crops to following cash crops have been conducted all over North America, but farmers still struggle to manage timely nitrogen (N) release from cover crops on their own land to match their cash crop peak demand. Managing N demands of vegetable crops on diversified farms in New England is particularly challenging given the high crop diversity with different nutrient needs (amounts and timing). Prior research resulted in the development of the Pre-sidedress Nitrate-nitrogen Test (PSNT) as a tool for nitrogen management in corn. We believe that the same test may be used effectively to monitor N mineralization from various cover crops to improve timing of N contributions to other vegetable crops beyond corn. There are over 1,400 vegetable farms in Massachusetts covering over 17,700 acres (USDA Agriculture Census, 2012) who could benefit from improved cover crop management and use of soil nitrate testing to determine crop N sufficiency. This proposed project will evaluate cover crop mixtures with diversified vegetable farmers to measure nitrogen availability and sufficiency from spring incorporated cover crops to subsequent summer vegetable cash crops.
Project objectives from proposal:
The main goals of this project are: 1) to expand evidence based N management for vegetable farmers who plant cover crops and 2) select cover crops with N mineralization rates that best match cash crop demands.
Five farmers who participated in a July 2016 workshop conducted by the MA SARE state program titled “How to conduct an on-farm trial” were trained in implementing the specific trial for this project on their own farms in the Fall of 2016. Experimental design (Fig 1) is identical for all farms including 4 replications and 3 broadcast seeded treatments: 1) No cover 2) Rye (70lbs/A) and Vetch (25lbs/A) 3) Farmer Choice (Table 1). Each treatment will be split in the spring after incorporating cover crops and an additional 60 lbs/A of N will be added to half of each plot to ensure that cash crops receive normal amounts of nutrition and the effect of cover crop N on yield can be measured. Figure 2 shows this experimental design. The project team distributed cover crop seed donated by Seedway at the beginning of the trial, assisted in cover crop establishment, and reviewed methods for rating % ground cover. Although not part of the original plan, we also sampled biomass from winterkilled cover crops and weeds to assess the C:N ratios and amount of N becoming available over the winter of 2016-2017 after the cover crops died. At the time of cover crop incorporation in May of 2017, the team will visit each farm again to collect biomass samples and farmers will receive training in PSNT sampling protocols. Soil samples for PSNT will be taken from each plot every 2 weeks over a period of 8 weeks to determine peak N-release time from the cover crops. At the end of the growing season, yield data will be collected from each plot. Cash crops grown will be farmer’s choice at each trial location.
A field walk will be hosted on 2 of the farms conducting the trial in 2017 and the farmers will present their experience with the trial (expected attendees: 10 Agricultural Service Providers and 30 Farmers). Advertising events and results of this trial will be published in Vegetable Notes and Crops, Dairy, Livestock Newsletter. Event notifications will also be distributed by MA team member mailing lists such as: NRCS, Southeastern MA Agricultural Partnership (SEMAP) and the New England Vegetable and Berry Growers Association (NEVBGA). Trial results will be published in 2 Extension publications reaching over 3,000 subscribers and submitted to HortScience if conducted for 2 years.