The University of Vermont Extension’s Champlain Valley Crop, Soil and Pasture Team recently wrapped up a two-year grant project bringing new manure injection technology to Addison County hay fields and pastures. 
Perennial forages are the largest crop by acreage in the state, providing important livestock forage for cows and other livestock. Perennial crops are typically at low risk for erosion as they have deep roots with permanent coverage of grass, legume and forb plants, which protect the soil surface and do not undergo tillage while in hay. However, they pose unique risk in comparison to annually cropped fields (like corn and soybeans) because all of the nutrients are usually applied on the surface, leaving them vulnerable to dissolved runoff — nutrients going into solution with water. This is of concern for phosphorus and Lake Champlain, as the dissolved form of phosphorus is a more potent food source for algae that blooms in the lake.
Over the years, farmers and custom manure applicators have fine-tuned the ability to inject liquid dairy manure in fields where we grow corn and soybeans, making manure less susceptible to runoff. For these annual crops, applying manure outside of the crop production window means the field has some capacity to withstand soil disturbance and not impact the main crop. However, in the past we did not have an ideal piece of equipment to accomplish the same results on hay fields and pastures. Previous attempts either left too much of the manure on the surface or caused too much damage to the hay crop through soil and root disturbance.
In 2017 we found a fantastic alternative — a shallow slot grassland manure injector. With funding from the Vermont Agency of Agriculture, Food and Markets’ Clean Water Fund and the help of Ken and Debbie Hicks at Hicks Equipment, we purchased the right equipment from the Netherlands. With the expertise of Eric Severy of Matthew’s Trucking to operate it, we began demonstrating the utility of this system. 
Shallow slot grassland manure injection gets liquid dairy manure just two inches below the soil where it is protected from runoff during rain events while still well within the root zone where the plants will use it. We purchased a 40-foot wide Veenhuis Euroject slurry injector and outfitted it to attach to a draghose manure system. We used a portion of the grant money to pay for the cost of injecting manure for farms willing to use the equipment.
After two summers of use, the situations that worked the best with the injector were immediately after harvesting hay (or grazing), during dry weather to maximize infiltration and increase nitrogen retention, and with thinner manure that is more prone to runoff losses. We look forward to finding more and better ways to use this equipment on Vermont farms. There is still a lot of work to be done investigating the impacts on nutrient runoff, crop yields and quality, and how to best use this technology, stay tuned.  
Kristen Workman is an Agronomy Specialist at UVM Extension.