WATER RESOURCES RESEARCH GRANT PROPOSAL
Project ID: 2004AR73B
Title: Nutrient losses in runoff and leaching from poultry litter applications to loblolly pine stands and pastures
Project Type: Research
Focus Categories: Nutrients, Water Quality, Non Point Pollution
Keywords: Runoff, poultry litter, leaching, nitrogen, phosphorus, arsenic, loblolly pine, best management practices
Start Date: 03/01/2004
End Date: 02/28/2005
Federal Funds: $18,241
Non-Federal Matching Funds: $36,635
Congressional District: 4th
Hal O. Liechty
Mike B. Daniels
The poultry industry in the United States produces massive amounts of poultry
litter that needs to be disposed of in an environmentally sound manner. In
Arkansas, broiler houses alone produce 1.3 million metric tons of litter annually.
This litter is commonly used to fertilize pastures. Research on pastures has
shown that excessive applications of poultry litter can negatively affect
the quality of surface and soil water and raise nutrient levels above water
quality standards. Poultry litter applications may also lead to unacceptable
high levels of arsenic and heavy metals in the environment. Poultry litter
applications to forests could be used to increase timber production and C
sequestration while, at the same time, expanding the options for litter disposal.
In the southern United States more than 530,000 ha of pine forests are fertilized,
and fertilization is estimated to increase productivity by 35% in intensively
managed plantations. Potentially, poultry litter could be routinely used in
forests in Arkansas because many landowners that produce poultry litter also
own forest land and/or are located within short distances of pine forests.
As seen for other types of waste, forests can absorb and retain relatively
large amounts of the elements found in poultry litter without causing environmental
problems. However, few planned field experiments have been initiated to investigate
the ability of forests to mitigate environmental impacts of poultry litter
applications. As part of a larger study, this proposed research will address
the impacts of poultry litter application on water quality in mature loblolly
pine stands and compare the impacts to those observed in pastures. Specific
1.quantify the impacts of poultry litter application to forests and pastures on sediment loads, nutrient and other environmentally important elements in surface water runoff.
2.quantify the impacts of poultry litter application to forests and pastures on nutrients and other environmentally important elements in soil water. Poultry litter will be applied to plots within a 13-ha loblolly pine plantation that is 26 years old as well as to plots within nearby pastures. Soil water will be sampled with tension lysimeters while surface runoff will be measured in runoff plots. Total suspended solids will be determined in runoff samples, and both runoff and soil water samples will be analyzed for NH3-N, NO3-N, SO4-S, total Kjeldhal N, total P, Ca, Mg, K, Na, As (V), Cu, Fe, Mn and Zn. Amounts of runoff, and fluxes and concentrations of the analyzed nutrients, As, and metals will be compared between plots that received the poultry litter and those that did not. Changes in nutrients, As, and metals in runoff and soil water by poultry litter applications in pine plantations will be compared to those in pastures. Comparisons will be made on an event, season, and the study period basis. Results will be made available to state and federal agencies related to water quality monitoring as well as to forest landowners and landowners associations. The study will help to develop Best Management Practices for poultry litter applications in forests. The experimental site will be also used for technology transfer and teaching activities of the Arkansas Forest Resources Center and the Arkansas Agricultural Experimental Station.