Spatial distribution of soil phosphorus, calcium, and pH after long-term broiler litter application

Authors: JIANG, YING-YING - Shenyang Agricultural University; SUN, ZHONG-XIU - Shenyang Agricultural University; Owens, Phillip; Adhikari, Kabindra; WANG, QIU-BING - Shenyang Agricultural University; DORANTES, MINERVA - University Of Arkansas; Read, John; Ashworth, Amanda; LIBOHOVA, ZAMIR - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2019
Publication Date: 4/18/2019
Citation: Jiang, Y., Sun, Z., Owens, P.R., Adhikari, K., Wang, Q., Dorantes, M.J., Read, J.J., Ashworth, A.J., Libohova, Z. 2019. Spatial distribution of soil phosphorus, calcium, and pH after long-term broiler litter application. Journal of Environmental Quality. 48:594-602. https://doi.org/10.2134/jeq2018.11.0406.
DOI: https://doi.org/10.2134/jeq2018.11.0406

Interpretive Summary: Poultry litter is a valuable fertilizer resource for forage and crops in the Southeast Area. However, when poultry litter or any fertilizer is over applied, the excess nutrients may end up in the waterways leading to deterioration of freshwater ecosystems. Soil sampling is key for understanding the soil nutrient levels and the potential need for optimum crop growth. Many producers sample on a grid or take only a few samples in the field to understand nutrient levels. This research identified locations within fields that my be higher in nutrients due to the topography of the field. This research found that water accumulates due to topographic controls, bring nutrients with it and that increases the nutrients in an area. Also, research found that areas where cattle congregate also have higher nutrient contents. Sampling based on landscape position is key to optimize application of poultry litter which increases profit while protecting stream water quality.

Technical Abstract: Water movement over and through soil is largely driven by topography and soil management across landscapes. This research tested the hypothesis that the water movement determines the potential for P and Ca redistribution and pH variance across landscapes. This hypothesis was evaluated by using digital elevation model-derived terrain attributes in fields after 55 yr of broiler litter applications on pastures in Smith County, Mississippi. Results show that soils receiving broiler litter had mean Mehlich-3 P levels of 1221.8 mg kg-1 at 0- to 15-cm depth and 618.6 mg kg-1 at 15- to 30-cm depth, and Ca with mean values of 768.3 and 645.0 mg kg-1 at 0- to 15-cm and 15- to 30-cm soil depths, respectively. Across fields, soils in areas of predicted convergent flow contained higher P, Ca, and lower pH values in the upper 0 to 15 cm, suggesting contributions via surface overland flow from areas with higher elevation and lower slope gradient. On the other hand, soils in areas with lesser slope and higher elevation also contained high levels of P, Ca, and pH for the subsurface soil depth, suggesting that vertical flow of water on this landscape is a mechanism for movement of P and Ca deeper in the profile. The incorporation of topographic characteristics across fields offers promising results that may be incorporated into improved P indices and management, making them more robust indicators of P mobilization to waterways