Evaluating the on-farm environmental and economic impacts of the use of aerators with liquid and semi-solid manure under various management conditions

Evaluating the on-farm environmental and economic impacts of the use of aerators with liquid and semi-solid manure under various management conditions

Summary

Jennifer Alexander met individually with each farmer to review project and what was expected from each farmer in March. In April, she and our intern set up the individual plots from the winter marking stakes on each farm. The intern also assisted with harvesting and data collection throughout the summer.
Diagrams of layouts on each farm are in the grant proposal. All research plots were on perennial cropland, with side-by-side plots that allowed for an experimental and a control area. Size of plots between farms varied based on the size of the aerator used (15’ or 8’9”), but were consistent within farms. Plots included a control, sections aerated once, aerated twice or aerated three times (if applicable). The control strip was not aerated. Aeration occurred prior to manure application in liquid systems and after application in semi-solid systems.

The following tests were conducted during the 2011 growing/research season:

Penetrometer readings on each plot, on all farms, occurred in April
Soil tests at the end of the crop season
Manure nutrient test
Forage samples were taken based on timing of aeration(Forage samples are being compared between plots, not between cuts).
Clover counts

In addition, the following data was collected:

Forage yields within individual plots were determined by hand harvesting and weighing of yield. Yields were weighed with a portable scale that has a certificate of accuracy within 3/4 pound. Scale was calibrated between plot measurements to ensure accuracy.
Dry Matter content was also evaluated between plots. Dr Sid Bosworth, UVM Extension, was consulted for proper protocols on this measurement.

Extensive digital photograph was done during aeration and within 24 hours of aeration to anecdotally evaluate infiltration and aerator holes.

Objectives/Performance Targets

Objectives/Performance Targets
1. Evaluate use of aerators for incorporation of manure on the farm scale level
Four farms participated. The above data was collected and is currently being evaluated. While further evaluation needs to occur, the following anecdotal information has been shared with farmers:
• Two farms that have used both the Aerway and GenTil units felt that the GenTil unit pulled less stones.
• There were differences in the penetrometer readings between the control and the 2 and 3 pass plots. Whether the difference is statistically different remains to be seen.
• As with 2010, there was no definitive difference seen in crop yield (both anecdotally and in research plots).
• As in 2010, we did not feel we had any data that could definitively conclude exact runoff control. Flow was influenced by manure consistency, amount of forage in the field and rate of application, but manure never seemed to “flow” directly into holes. Measurement of exactly infiltration is far beyond the scope and ability of our research, however we will continue anecdotal visualizations.

2. Provide information and education to farmers in the area about the project as well as overall recommendations and best management practices for use of the aerator.
• 2 Aerator Demonstrations were held in August. One at a research farm in Clarendon on August 12th, and another at a non-research farm in Wells on August 22nd.
• A workshop was held on March 7th to discuss the Year One results of the Aerator trials. This workshop was held at the East Poultney Baptist Church in Poultney.
Data collection will end in spring of 2012

Accomplishments/Milestones

Accomplishments/Milestones
The research and data collection part of the project went mostly according to plan. Unfortunately, we had a very wet spring and only 1 of the research farms was able to harvest 1st cut at a reasonable time. On 3 of the farms, first cut was exceptionally wet, over grown, and of poor nutritional value. Due to this we did not collect 1st cut harvest data on those farms. Third cut was also a challenge due to Tropical Storm Irene and the weeks of on and off again rain that followed. Because of this, harvest data and forage samples were collect by hand as none of the farms that had planned on a 3rd cut felt that they would be able to do it. One of the research plots was under water for 3 weeks after Tropical Storm Irene. Remarkably the flags in the plots were not swept away by the flood waters. There was a noticeable increase in ash content in his forage tests.

Impacts and Contributions/Outcomes

Impacts and Contributions/Outcomes
Farmers are still hesitant to use the aerator unless there is a direct monetary benefit to them in the form of CCPI or FAP payments. The smaller diversified and grazing farms seem more willing to try aeration, especially in their pastures, than the larger confinement dairy farms. We suspect this is mostly due to time constraints and the low direct monetary return from aeration. While we believe that over time there will be improvements to the soil in the form of reduced soil compaction in the top six inches that could lead to better water and nutrient utilization, that does not provide a direct financial benefit immediately. Our educational approach for this practice will need to include both short and long term benefits.

Collaborators: