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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #328890

Research Project: ENHANCED MODELS AND CONSERVATION PRACTICES FOR WATERSHED RESOURCE MANAGEMENT AND ASSESSMENT

Location: Grassland Soil and Water Research Laboratory

Title: Assessment and synthesis of 50 years of published drainage phosphorus losses

Author
item Christianson, L - University Of Illinois
item Harmel, Daren
item Smith, Douglas
item Williams, Mark
item King, Kevin

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2016
Publication Date: 9/16/2016
Publication URL: http://handle.nal.usda.gov/10113/5510076
Citation: Christianson, L.E., Harmel, R.D., Smith, D.R., Williams, M.R., King, K.W. 2016. Assessment and synthesis of 50 years of published drainage phosphorus losses. Journal of Environmental Quality. 45:1467-1477. doi:10.2134/jeq2015.12.0593.

Interpretive Summary: The wide spread use of artificial drainage systems in intensively cropped areas across North America combined with the importance of freshwater resources in these regions has created a critical intersection where understanding drainage phosphorus (P) transport is vital. In this study, drainage nutrient load data were reviewed and analyzed to develop a more comprehensive understanding of the P loading and crop yield impacts of agronomic management practices within drained landscapes. Using the new Drain Load table in the "Measured Annual Nutrient loads from AGricultural Environments" (MANAGE) database, the effect of factors such as soil characteristics, tillage, and nutrient management on drainage P loading were analyzed. Across site-years, generally less than 2% of applied P was lost in drainage which corroborates the large difference between agronomic P application rates and P loadings that can contribute to water quality degradation. The practice of no-till significantly increased drainage dissolved P loads compared to conventional tillage (0.12 versus 0.04 kg P/ha). The timing and method of P application are both known to be important for drainage P losses, but these conclusions could not be verified due to low site-year counts. Findings indicate there is a substantial need for additional field-scale studies documenting not only drainage P losses, but also important cropping management, nutrient application, soil property, and drainage design impacts on such losses.

Technical Abstract: The prevalence of artificial drainage systems in intensively cropped areas across North America combined with the importance of freshwater resources in these regions has created a critical intersection where understanding drainage phosphorus (P) transport is vital. In this study, drainage nutrient load data were reviewed and quantitatively analyzed to develop a more comprehensive understanding of the P loading and crop yield impacts of agronomic management practices within drained landscapes. Using the new Drain Load table in the "Measured Annual Nutrient loads from AGricultural Environments" (MANAGE) database, the effect of factors such as soil characteristics, tillage, and nutrient management on drainage P loading were analyzed. Across site-years, generally less than 2% of applied P was lost in drainage which corroborates the order of magnitude difference between agronomic P application rates and P loadings that can cause deleterious water quality impacts. The practice of no-till significantly increased drainage dissolved P loads compared to conventional tillage (0.12 v. 0.04 kg P/ha). The timing and method of P application are both known to be important for drainage P losses, but these conclusions could not be verified due to low site-year counts. Findings indicate there is a substantial need for additional field-scale studies documenting not only drainage P losses, but also important cropping management, nutrient application, soil property, and drainage design impacts on such losses.