Location: Soil Dynamics ResearchTitle: Determination of phosphorus loss in runoff from soils with different soil test phosphorus ratings
|BHATTA, A - Auburn University|
|PRASAD, R - Auburn University|
|CHAKRABORTY, D - Auburn University|
|Torbert, Henry - Allen|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/2021
Publication Date: 11/7/2021
Citation: Bhatta, A., Prasad, R., Chakraborty, D.B., Watts, D.B., Torbert III, H.A. 2021. Determination of phosphorus loss in runoff from soils with different soil test phosphorus ratings [abstract]. ASA, CSSA, SSSA International Annual Meeting, Nov. 7-10, 2021, Salt Lake City, UT.
Technical Abstract: Phosphorus (P) application at rates greater than the crop requirement leads to build up of soil P level in agricultural lands. Soils containing high P concentrations when transported via surface runoff during storm events can accelerate eutrophication in water bodies. The objective of this study was to evaluate the differences in P loads in runoff water from soils having distinct soil test P ratings (STP) and determine the differences in P loads in immediate and subsequent rainfall occurring within 24 hours. Artificial rainfall simulations on runoff plots were conducted at 4 sites on a hay field receiving swine effluent multiple times during the year. Among the 4 sites, 1 and 2 had “extremely high” STP rating whereas site 3 had “high” and 4 had “very low” STP rating. The runoff samples were analyzed for dissolved reactive P (DRP) and total P. Flow weighted mean concentration (FWMC) was calculated as the mass of nutrient loss (total load) in 30 minutes runoff duration divided by the total volume of runoff during that period. Phosphorus loadings in runoff for each site was determined by multiplying FWMC and the total discharge. In the first rainfall simulation, the sites with “extremely high” and “high” STP ratings (i.e., sites 1, 2 and 3) had a DRP loading of 35 g ha 1, 258 g ha 1 and 65 g ha 1, respectively. The minimal DRP loading (7 g ha 1) was found at site 4 which had “low” STP ratings. After the second rainfall simulation (performed 24 hour after the 1st simulation) the total DRP load were 35 g ha 1, 251 g ha 1, 57 g ha 1 and 15 g ha 1 for sites 1, 2, 3 and 4, respectively. The findings suggested that the soils with higher STP levels are of greater environmental concern and best management practices to reduce P loadings should be implemented wisely.