RT Journal Article
SR Electronic
T1 Nitrogen and phosphorus runoff from cropland and pasture fields fertilized with poultry litter
JF Journal of Soil and Water Conservation
FD Soil and Water Conservation Society
SP 400
OP 412
DO 10.2489/jswc.64.6.400
VO 64
IS 6
A1 Harmel, R.D.
A1 Smith, D.R.
A1 Haney, R.L.
A1 Dozier, M.
YR 2009
UL http://www.jswconline.org/content/64/6/400.abstract
AB Application of litter and other organic by-products to agricultural land off site of animal production facilities has created both environmental concerns and agro-economic opportunities, but limited long-term, field-scale data are available to guide management decisions. Thus, the objective of this study was to determine the water quality effects of repeated annual poultry litter application as a cropland and pasture fertilizer. Eight years of data collected on ten field-scale watersheds indicated several significant water quality differences based on litter rate (0.0 to 13.4 Mg ha−1 [0 to 6 ton ac−1]) and land use (cropland and pasture). On cropland fields, increasing litter rates (with corresponding decreases in supplemental inorganic nitrogen [N]) increased runoff orthophosphate phosphorus (PO4-P) concentrations but reduced extreme high nitrate nitrogen (NO3-N) concentrations. Whereas runoff PO4-P concentrations were somewhat similar between land uses, NO3-N concentrations were much lower in pasture runoff because of supplemental inorganic N application, reduced nutrient uptake potential, and faster litter mineralization on cropland. Although considerable variability was observed, intra-annual runoff NO3-N and PO4-P concentrations generally exhibited curvilinear decay based on time since fertilizer application. In spite of repeated annual litter application and buildup of soil phosphorus (P) at high litter rates, few long-term trends in N and P runoff were evident due to the dynamic interaction between transport and source factors. These results support several practical implications, specifically: (1) combining organic and inorganic nutrient sources can be environmentally friendly and economically sound if application rates are carefully managed; (2) high runoff N and P concentrations can occur from well-managed fields, which presents difficulty in regulating edge-of-field water quality; and (3) change in the animal industry mindset to view by-products as marketable resources could mitigate environmental problems, provide alternative fertilizer sources, and enhance animal industry revenue opportunities. © 2009 by the Soil and Water Conservation Society