Not your grandpa’s poultry litter stockpile
By Treena Hein
New research into best management practices for stockpiling and application of poultry litter to cropland is being investigated at Kansas State University.
By Treena Hein
Poultry producers in Arkansas, Missouri, Oklahoma and other areas of the United States and Canada are dealing with added nutrient management regulations on a continuous basis. Insight into best practices in stockpiling and application is critical.
Dr. Peter Tomlinson and agronomy graduate student Barrett Smith are now two years into a large research project evaluating improved storage sites for stockpiling of poultry litter for application to crop land. Dr. Tomlinson has been an assistant professor and extension specialist for environmental quality at Kansas State University since 2011 and his interest in studying manure and nutrient management began during his undergraduate years at the University of Connecticut.
“Poultry producers in Arkansas, Missouri and Oklahoma continue to face nutrient management regulations,” Dr. Tomlinson notes. “Kansas row crop producers in the southeast corner of the state are looking for cost-effective sources of N, P, and K and have found that poultry litter can cost effective way to meet their P, K and a portion of their N requirements. However, before the litter is applied it must be stored, and stored properly. The keys to a good storage site are that it’s accessible in all-weather conditions, is at least 300 feet away from water, has the ability to exclude extraneous drainage, and has an adequate buffer area before the runoff reaches water.”
This is exactly what Dr. Tomlinson has been studying, and he uses the word “encouraging” to describe his and Smith’s preliminary research findings from the last two years.
“Our initial look at the data is encouraging based on flow-weighted mean concentrations of run-off nutrients,” he explains. “We are in the process of calculating total load losses from the pad and buffer, which will allow us to determine if we are retaining the nutrients lost from the pad in the buffer area.”
From previous research and experience in small feedlot design, a chicken litter storage site evaluation sheet [agronomy.k-state.edu/extension/environmental-quality/poultry_litter/index.html] and improved storage site specifications have been developed by Herschel George – Kansas State Research and Extension watershed specialist – and Dr. Tomlinson, with input from state agency personnel, the Kansas Farm Bureau and local watershed restoration and protection strategy groups. Dr. Tomlinson says the evaluation tool can be used to identify suitable locations for developing an improved storage site as well locating suitable locations for short-term in field storage of poultry litter. The lowest score possible (lowest risk possible of detrimental runoff) is desirable.
The general guidelines for litter storage sites include:
- Elevated earthen pad to eliminate ponding of water at the storage site
- Extraneous drainage diverted around the storage site
- From four- to six-inches of agricultural lime or equivalent added to provide an elevated level pad to store poultry litter
Year-round access to the storage site is also critical, says Dr. Tomlinson.
“In conversations with poultry litter brokers/transporters, they have indicated that they really like good all-weather access of the service entrances. What we mean by ‘all-weather’ access is access from a gravel road whereby a semi-truck with a 40-foot trailer can access the pad, even when weather conditions are rainy and or soil conditions are wet and might cause the semi to get stuck.”
Dr. Tomlinson notes that when the popularity of poultry litter increased in southeastern Kansas because fertilizer prices went up, one of the major issues was fear of getting stuck. He explains that drivers would only back the trailer into the field. By the time they finished off-loading the litter, the end of the pile was near or in the road ditch, and/or the trailer had left ruts where runoff was funneled directly into the ditch.
Dr. Tomlinson adds that producers have found the agricultural lime base of the storage pad is helpful when they are loading the manure for spreading because it gives a visual indicator that they have reach the bottom of the pile.
Farmers also need to exclude extraneous drainage from their poultry litter storage sites by limiting water from a higher landscape position from entering the site, obviously because adding water to the runoff that’s already being filtered through the buffer is not desirable.
“This typically involves constructing an earthen berm, during the pad construction building phase, that directs water that would normally run onto the pad away from, and around, the pad,” Dr. Tomlinson explains. “The other option is to find storage locations sites that are at the top/crest of a landscape position such as the top of a hill. The key here is minimizing the water that has to be treated through the buffer to just that which is coming from the storage pad.”
In terms of best practices in creating a sufficient buffer between the storage area and natural bodies of surface water such as streams, Dr. Tomlinson says the storage site location should be at least 300 feet away. The distance from the pad to the edges of occasionally or frequently-flooded soil should be factored in as well (on the storage site evaluation sheet, the greater the distance, the lower the score).
“We have also given different buffer types different values on the evaluation sheet,” explains Dr. Tomlinson. “Dense grass is a more efficient buffer than crop ground, for example. However, this is coupled with the buffer size calculation. So if you have crop ground present, you can reduce the score (risk) by increasing the buffer size. If the area is limited in size, then establishing a grass buffer would reduce your score.”
The project will be continuing for two more years. Although Dr. Tomlinson has only studied storage of broiler chicken litter, he anticipates that the principles and best management practices would be the same for turkey litter.
Kansas State University Soil Science Professor Dan Sweeney and colleagues have compared the application of fertilizer and turkey litter to sorghum grown in clay pan soils (common in Kansas) and found that application of litter is a viable option. At the eight-leaf stage, there were no significant differences between fertilizer and/or turkey litter treatments.
“I haven’t done any price comparisons,” Dr. Sweeney says. “Pricing can certainly be important to producers, but with swings in fertilizer pricing and maybe litter pricing too, it can vary whether it is a cost savings to use poultry litter or commercial fertilizer.”
However, Dr. Sweeney says applying turkey litter annually to clay pan soils must be done carefully.
“Poultry manure has a greater ratio of P to N in comparison to other manures, so if poultry litter application is based on the crop’s N needs instead of its P needs, P can be greatly over-applied.”
Dr. Sweeney and colleagues have also studied nutrient run-off from application of turkey litter versus fertilizer. He found that run-off rates from fertilizer were usually lower than from N-based, and similar to P-based, turkey litter applications.
“Incorporation of the litter reduced the nutrient losses in runoff, but it didn’t always make any significant difference,” he explains. “Applying a lot of litter will build up soil P levels, and annual P runoff losses can accelerate when soil P values are very high.”
The chicken litter storage site evaluation sheet is available here: