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

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

Summary

The purpose of this project is to extend the fall dairy grazing season using intercropped forage radish (FR) and oats. In September 2015, six ratios of FR to oat were planted after manure application in order to study yield potential, land equivalent ratios (LER), nutrient capture from fall applied manure, glucosinolate (GL) content of different rations, and changes to free-living and plant parasitic nematode populations in the soil. We aim to optimize yield and feed value of fall forage production, while maximizing nutrient capture of N&P from fall applied manure. We also aim to encourage populations of free-living nematodes while minimizing plant-parasitic nematodes.  Our overarching goal is to develop a system that facilitates economic gains through sustainable management practices using dual-purpose cover crops.

Objectives/Performance Targets

INDIVIDUAL OBJECTIVES:

1. 1. Determine the (LER) of FR and oats
      2. Determine the ratio of FR and oats with the greatest RFV
      3. Assess levels of GL in each ratio
      4. Define changes to GL levels across individual plants to determine the effect, if any, of planting ratios on GL production
      5. Measure crop N&P capture from fall applied manure
      6. Identify changes to free-living and plant-parasitic nematode populations under different planting ratios, and assess these changes relative to soil organic matter (SOM) and root GL production.

OVERALL OBJECTIVES:

1. 1. Reconcile yield, RFV, GL content, effects on nematode populations, and nutrient capture to determine the optimum FR to oat planting ratio for use as a dual-purpose fall cover crop and grazing crop.
      2. Conduct outreach to disseminate information and recommendations through individual communication, dairy meetings, research conferences, annual field day events, newsletters, and factsheets.

Accomplishments/Milestones

This past fall of 2015, a field experiment with three replications was conducted in order to study our individual objectives. Six planting ratios of FR to oat were planted after manure application. Throughout the fall, soil samples were taken to assess soil N&P, SOM, and nematode populations. When weather conditions suggested winterkill of the crops was imminent, final soil samples were taken, as well as tissue samples to analyze yield, LER, RFV, nutrient uptake, and GL content. All samples are actively being processed and analyzed in order to assess our preliminary results.

In the spring of 2016 soil samples will be taken to assess nematode populations, SOM, and soil nutrient levels, which will conclude sampling of the first year. All samples are expected to be analyzed by the end of the summer of 2016.   

Impacts and Contributions/Outcomes

This research is generating necessary information to encourage and facilitate dual-purpose cover cropping on dairy farms. Adding economic value to cover crops by studying their potential for extended grazing encourages farmers to prioritize their planting; this in turn results in better nutrient management of fall-applied manure, and it creates the opportunity for improved soil quality. Beyond studying nutrient cycling and yield potentials, this work also considers the quality of forage as influenced by GL, and questions the impact intercropping may have on this secondary-metabolite production. With this in mind, we address animal health through safe feed and palatability, while extended grazing translates to quality of life. Finally, monitoring changes to nematode populations helps us understand the effects of our cropping strategy on an important animal population in our soil that has great potential to impact subsequent cash crop production.

Our research approach will provide comprehensive management information for farmers who wish to implement this dual-purpose cropping strategy.

Collaborators: