Simple methods to stack manure and make compost without nutrient loss

Simple methods to stack manure and make compost without nutrient loss

Summary

This project conducted on-farm studies of methods to stack manure with minimal loss of nutrients from the manure stack. The technology developed will also be applicable to making compost, because stacking manure requires the addition of carbon in some form to make the manure stackable. Without the addition of carbon, manure when placed in a field is a shallow, self-leveling pancake, not a stack. By layering an organic material above and below a stack of farmyard manure, farmers can influence the amount of ammonium and nitrate that move form the manure pile into the soil. This project’s preliminary results are promising, with clear and significant treatment differences.

Objectives/Performance Targets

Building on the ideas of several Connecticut dairy farmers, the objective of this project was to develop methods to stack fresh barnyard manure that minimize the amount of nutrients that escape from the manure stacks.

Accomplishments/Milestones

Four new farmers were recruited to participate in on-farm studies. Each of these farmers made 8 (2 replications of 4 treatments) test stacks with farmyard manure in the fall of 2003. They used available old hay as a carbon source for layering above and below the stacks. As a control, manure was also stacked, without layering of any organic material, a typical farmer practice. Prior to stacking, soil was sampled below and immediately adjacent (down slope) of the area to be occupied by each stack. A background area where no manure or compost was stacked was also sampled. The piles remained in the field for 6-7 months. They were not turned. In spring 2004, the piles were removed and the soil sampled again. All samples were collected from the surface 1-foot of soil and were analyzed for ammonium and nitrate. Pre-stacking values were compared with post -stacking values as indicators of possible loss of nutrients or other soluble compounds from the treatment stacks.

Results varied with the initial quality/age/nutrient content of the manure used in the stacks, but overall trends were similar. The farm that used fresh manure in its stacks had similar results to the farmers that initiated the experiment. The layering of old hay above and below a stack of dairy manure appears to greatly reduce the loss/movement of ammonium and nitrate from the stacks; nearly to background levels. Layering an organic material either above or below a stack also reduces nutrient movement form the stack to the soil, but not to the same extent. Ammonium levels appear to be more influenced by the use of a layer of organic material than nitrate. Stacking manure without any layer(s) of organic material results in elevated concentrations of soil nitrate and ammonium, presumably that has moved from the manure stack.

The on-farm trial results were presented at a field day at Russ Wheeler’s compost site in western Connecticut in September 2004. About a dozen farmers and agency field personnel attended. Results of these experiments have been presented by Tom Morris at meetings for dairy farmers held each year in the eastern and western sections of Connecticut, and at the CCA meeting for New England held at Portsmouth, NH in February 2004. The results will also be discussed and shared at the annual Farmer Research Group meeting in February 2005. The farmers who participated in the on-farm trials will discuss their results at another field day which will be held at the University of Connecticut’s Research Station in Storrs on March 29, 2005.

Impacts and Contributions/Outcomes

This technique has potentially great impact. It may result in new practice standards or BMP recommendations, because it demonstrates the potential of new environmentally acceptable, cost effective options for manure or compost management, particularly for moderate and smaller scale farms.The project’s preliminary results also demonstrate the value of farmer ideas and farmer-scientist collaborations.

ln 2004, a graduate student established a replicated, controlled experiment with the same treatments plus some additional treatments on the University of Connecticut’s Research Station. This will allow the farmers who attend the field day to understand how on-farm and station experiments apply to their farming operations.

On-farm and research station follow-up studies will continue.

Collaborators: