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

Project planning meetings took place immediately upon grant award with project leaders and UVM Extension System professionals to discuss details of project including data collection, analysis, size and structure of research plots, and coordination.

Jennifer Alexander met individually with each farmer to discuss the project details. In May, she and intern Michael Middleman staked out plots and again discussed exact procedures with each of the four participating farmers. Diagrams of layouts on each farm are attached in Appendix A. 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 2010 growing/research season:

Soil tests at the beginning and end of the crop season
Cornell Soil Health test
Manure nutrient test
Forage samples were taken based on timing of
aeration(Forage samples are being compared between plots,
not between cuts).

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 be calibrated daily to ensure accuracy.

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

• Appendix A -Diagram of farm plot layouts

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 farmers who used the 15’ aerator on hard clay felt the GenTill was too light, even with added weights, and they preferred the Aerway.

  • The holes created by the aerator in clay soils seemed to close up more quickly than the sandy or silty loams which surprised us. Even when the Hamlin Silt Loam plot was flooded several times, holes were still visible whereas the Vergennes Clay closed up quickly.

  • Aeration on wet soils can be very detrimental by tearing up sod

  • Farmers with severe compaction felt the aerators were extremely beneficial in helping with this concern.

  • No apparent affect to the crop stand with multiple passes of the aerator (maximum of 3) though it is necessary to evaluate winter kill to confirm

  • Clover seemed to thrive with the disturbance, though this must be replicated under different growing seasons for confirmation

  • No definitive differences were seen in crop yield (both anecdotally and in research plots). Several farmers felt that it was valuable to disturb the roots of permanent sod

  • Small aerator was very effective as a tillage tool for reseeding a hayfield

  • We did not feel we had any data that could definitively conclude exact runoff control. We had our intern in the field watching manure after rain on several events. 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.

  • Articles about the project were included in three issues of the Spreading Times newsletter which reaches 700 producers and partners.

  • A field day was held at one of the participating farms on October 12, 2010 to demonstrate the aerator and discuss the project.

  • A workshop for farmers to discuss results will be held on March 6, 2011.

  • We also were able to secure funding to continue this project through the growing season of 2011 from the Lake Champlain Basin Program.

Accomplishments/Milestones

The research and data collection part of the project went mostly according to plan. We realized early on that the plots are far too large for hand collection to evaluate yield, and will decrease plot size in the second year of the project. We also realized (as expected) that it is impossible at this size scale and science to attempt to quantify runoff, however we expected to see some indications of this in our visual documentation (photographs, inspection of individual holes in the field, etc). Our intern visually examined aerator holes within 12-24 hours of rainfall, and it was clear that many factors influence the infiltration (as explained above).

We are also very pleased to have a second year to continue these plots. Several uncontrollable factors such as rainfall affect the results with the aerator, and we look forward to having a second year for data comparison for farmers.

Impacts and Contributions/Outcomes

Farmers are hesitant to try any new practice until they have seen it done elsewhere (preferably on a neighbor’s farm). In addition to conducting the research plots, we have encouraged the use of the aerator by other farmers throughout the watershed, and have seen increased interest as the season progressed. The data results of the research are critical, but the secondary value of the having the aerators in extensive use is increasing the practice use and implementation.

This year (2011) we also have a new employee, a full-time agronomist who can help promote and educate about this tool and encourage additional implementation, as well as monitor individual changes, experiences and outcomes.

• Photos of aerator passes
• Measured plots – photo
• Photos -disturbance with aerator

Collaborators: