Dual purpose cover crops for grazing season extension, nematode management, and improved resiliency on dairy farms

View the project final report

• 2015 annual report
• 2016 annual report

Commodities

• Agronomic: oats, radish (oilseed, daikon, forage)
• Animals: bovine
• Animal Products: dairy, meat

Practices

• Animal Production: animal protection and health, feed/forage, feed rations, manure management
• Crop Production: cover crops, nutrient management
• Education and Training: demonstration, extension, on-farm/ranch research, technical assistance, workshop
• Pest Management: biofumigation

Fall planted forage radish (FR) and oats have the potential to provide resiliency and sustainability to dairy farmers by extending the grazing season, increasing forage production, and maximizing N&P capture from fall-applied manure. Developing quality, dual-purpose cover crop systems will encourage farmers to plant cover crops that prevent soil erosion and build soil organic matter. However, FR produces glucosinolates, which naturally hydrolyze to toxic compounds that can have adverse effects on dairy cows or nursing offspring when consumed in high quantities; excessive glucosinolates in feed rations can also result in decreased palatability and consumption. Conversely, glucosinolates could influence soil nematode populations, possibly reducing plant-parasitic nematodes due to toxicity and competition from bacterivore nematodes that feed on bacteria decomposing FR roots. As FR continues to gain popularity as a cover crop and for grazing, more information about glucosinolates is needed. Research is lacking in the quantification of glucosinolates in feed rations, and few studies explore the effects of fall cover crops on nematode populations in this region. In our experiment, we will develop an oat and FR planting ratio that results in the greatest yield and lowest glucosinolate content, provides a high RFV, and captures substantial amounts of N&P from fall-applied manure. We will also study the effect of intercropping, i.e. competition, on production of the plant secondary metabolites, glucosinolates, by FR. Furthermore, we will assess changes to both free-living and plant-parasitic nematodes under each ratio in order to understand how cover cropping influences, and can potentially manage, nematode populations.

Our overarching objective is to develop and disseminate technical information to New England dairy farmers that will encourage grazing season extension practices, resulting in savings for farmers, improved nutrient management of fall applied manure, and increased regional resiliency to economic fluctuations.

Specifically, we aim to:

1. 1. Determine the Land Equivalent Ratio (LER) of forage radish to oats and maximum yield.
      2. Determine the ratio of forage radish to oats resulting in the greatest RFV.
      3. Assess levels of glucosinolates in each ratio to minimize consumption by dairy cows to A. reduce the possibility of potentially negative side effects and B. increase palatability, and therefore consumption.
      4. Define changes to glucosinolate levels in individual plants to determine the effect of planting ratio on glucosinolate content.
      5. Measure crop nutrient acquisition, specifically nitrogen and phosphorous, from fall-applied manure to identify the ratio with the greatest nutrient capture potential.
      6. Identify changes to free-living and plant-parasitic nematode populations under different planting ratios; assess these changes relative to soil organic matter and root glucosinolate production.
      7. Reconcile yield, RFV, levels of glucosinolates, effect on nematode populations, and nutrient capture to determine the optimum forage radish to oat planting ratio.
      8. Conduct outreach to disseminate information and recommendations through individual communication, dairy meetings, research conferences, annual field day events, newsletters, and factsheets.