US broiler farms monitor nutrient runoff practices

The Arkansas Discovery Farm Program (ADF) monitors water quality on private working poultry farms to document the true impacts of agricultural production on environmental quality and efficiency of current conservation measures.

The Arkansas Discovery Farm Program monitors water quality on private working poultry farms to document the true impacts of agricultural production on environmental quality and efficiency of current conservation measures. | graphicphoto, Bigstock.com
The Arkansas Discovery Farm Program monitors water quality on private working poultry farms to document the true impacts of agricultural production on environmental quality and efficiency of current conservation measures. | graphicphoto, Bigstock.com

The Arkansas Discovery Farm Program (ADF) is a stakeholder-led research and development program that monitors water quality on private working poultry farms to document the true impacts of agricultural production on environmental quality and efficiency of current conservation measures. Being conducted on private broiler farms, these results resonate with the poultry farming community. In many cases, neighboring poultry farmers are voluntarily introducing additional conservation practices to further reduce nutrient runoff after seeing the results. Most importantly, the ADF Program is empowering farmers to proactively address environmental concerns.

Nutrient enrichment remains a major impairment to the designated uses of fresh and coastal waters of the United States. While there are many sources of nutrients, the contribution of agriculture has received increased attention to reduce nutrient losses. This attention has been fueled by recent modeling efforts and surveys which suggest agriculture contributes up to 85 percent of the phosphorus (P) and nitrogen (N) entering the Gulf of Mexico. However, there have been few farm-scale studies of phosphorus and nitrogen loss from agriculture in the Basin, particularly the Lower Mississippi River Basin.

Government, NGOs, poultry groups cooperate in ADF

Several state government (Natural Resources Conservation Service, Arkansas Association of Conservation Districts, and Arkansas Natural Resources Commission), non-profit organizations (Nature Conservancy and Walton Family Foundation) and producer groups (Poultry Federation and Arkansas’s cotton, rice and soybean boards) have combined to support the Arkansas Discovery Farm Program.

The ADF program brings these groups working together to identify on-farm conservation issues and potential solutions to agricultural sustainability challenges. The ADF is based on four cornerstones; 1) sound science, 2) unbiased research, 3) stakeholder driven transparency, and 4) strong partnerships. Currently there are 11 Discovery Farms operating across Arkansas, as shown in Figure 1.

Arkansas-Discovery-Farms

Figure 1. The Arkansas Discovery Farms include the production of a variety of agricultural commodities, including poultry.

Cost effectiveness of practices to reduce nutrient runoff

In northwest Arkansas, we are assessing the potential for nutrient runoff from around poultry broiler production facilities on three ADFs and one University farm. Here we are determining the cost effectiveness of several conservation practices to minimize any nutrient runoff that might occur. These practices include grassed waterways, berms to redirect runoff from poultry houses, larger concrete pads at the front of poultry houses to allow easy cleaning of spilt poultry litter during routine house operations (Figure 2), and by-product residuals to trap phosphorus on site.

Concrete-pads-help-reduce-nutrient-runoff

Concrete-pads-help-reduce-nutrient-runoff

Figure 2. Runoff is collected from two sets of poultry houses, one with traditional gravel entrance pads (top) and newly constructed concrete pads (bottom) which allow cleanup of cleanout spillage.

Generally, three to four sites (fields) are equipped with monitoring stations, which allow for comparison of the management of two to three scenarios to a control. At each site, state-of-the-art equipment is installed to measure surface runoff and automatically collect runoff (Figure 3). Samples are brought to the lab within eight hours of collection and analyzed for phosphorus (as dissolved and total P), nitrogen (as nitrate-N and total N), and suspended solids, following U.S. Environmental Protection Agency methods.

Sampling-of-nutrient-runoff

Sampling-of-nutrient-runoff

Figure 3. Automated samplers collect water during runoff from two set of poultry houses

On one farm, surface runoff from around two poultry houses is sampled before and after passing through a grassed waterway (NRCS Conservation Practice 412 – see https://goo.gl/vmwqo5) of approximately 670 feet (200 meters) to determine the efficiency of the grassed waterway to decrease nutrient runoff, prior to entering a stream. The loss of phosphorus and nitrogen in runoff from two poultry houses decreased by over 50 percent after passing through the unfertilized, ungrazed pasture (see Table 1). In fact, the loss of phosphorus and nitrogen was less than measured in runoff from a monitored pasture approximately 10 miles away, to which poultry litter was broadcast annually at a rate of 1.3 tons acre-1 year-1 from 2012 to 2015 (see Table 1). A point of note here is that loss of the phosphorus and nitrogen from the pasture was only 0.2 percent of that applied annually in poultry litter.

Grassed-waterway-to-reduce-nutrient-runoff

Table 1. Annual nutrient runoff from two poultry houses is compared before and after passing through a grassed waterway and from a fertilized pasture in the same area, averaged for 2012 to 2015.

Concrete pads reduce reduces nutrient runoff

One year of runoff data from around poultry houses with an expanded concrete front pads that allows for easier cleanup, and four houses with traditional small concrete and gravel front pads, shows total phosphorus and nitrogen runoff is over 50 percent lower with the expanded concrete pads. Although, this is too short a monitoring period to draw reliable conclusions, it does show the potential benefits of this measure. Monitoring is continuing.

On the University-operated poultry research farm, we are evaluating the use of two locally sourced byproducts, red-mud iron tailings from steel-belt production and a residual from the area drinking water treatment facility, to trap phosphorus adjacent to the poultry houses. These byproduct materials previously land filled, can still bind large amounts of phosphorus added to them (Figure 4). By placing these byproducts in removable trays below exhaust fans, red muds decreased potentially leached phosphorus from 11.0 mg L-1 to 0.7 mg L-1 and water treatment residual to 1.1 mg L-1. The beneficial use of these byproducts as a future conservation practice continues to be investigated.

Byproducts-filter-phosphorus-from-runoff

Figure 4. Red mud iron tailings remove 98 percent of added phosphorus. Water treatment removes 92 percent of added phosphorus.

Recommended practices to reduce nutrient runoff

Results from the ADF program demonstrate that the loss of phosphorus and nitrogen in runoff from around poultry houses is only slightly greater than that from pastures fertilized with poultry litter to meet the phosphorus requirements of warm season grasses. However, we are documenting the effectiveness of several conservation practices, which might be adopted by farmers to further minimize nutrient runoff. Practices that we recommend to minimize nutrient runoff from broiler production facilities are listed in Table 2. In the next three years, the ADF should be able to provide reduction efficiencies for these practices, along with estimates of cost-reduction benefits.

Recommended-practices-to-reduce-nutrient-runoff

Table 2. These conservation practices are recommended to minimize nutrient runoff potential from broiler poultry production facilities.

 

Read more:

Poultry renderer recognized for wastewater reclamation, www.WATTAgNet.com/articles/28628

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