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United States Department of Agriculture

Agricultural Research Service

Research Project: INNOVATIVE ANIMAL MANURE TREATMENT TECHNOLOGIES FOR ENHANCED ENVIRONMENTAL QUALITY

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Erosion control practices integrated with polyacrylamide for nutrient reduction in rill irrigation runoff

Authors
item Szogi, Ariel
item Leib, B - UNIV. TN, KNOXVILLE
item Redulla, C - WA STATE UNIV., PROSSER
item Stevens, R - WA STATE UNIV., PROSSER
item Mathews, G - WA STATE UNIV., PROSSER
item Strausz, D - WA STATE UNIV., PROSSER

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 17, 2007
Publication Date: May 16, 2007
Citation: Szogi, A.A., Leib, B.G., Redulla, C.A., Stevens, R.G., Mathews, G.R., Strausz, D.A. 2007. Erosion control practices integrated with polyacrylamide for nutrient reduction in rill irrigation runoff. Agricultural Water Management. 9l:43-50.

Interpretive Summary: Application of polyacrylamide (PAM) is an economical practice rapidly adopted in the Yakima River Basin, Washington, that substantially reduces soil erosion in rill irrigation and improves water quality in irrigation return flows. Yet, several Yakima River tributaries need to meet the regulatory sediment concentration standard (total maximum daily load or TMDL) and should have plant nutrient levels below reference values recommended by USEPA guidelines. A two-year field study was conducted that combined PAM application with the following four conservation practices: 1) check dams, 2) surge irrigation, 3) surface drains, and 4) grass filter strips. The study was conducted at three sites: two vineyards (A and B) and a cornfield. During irrigation events, water samples and flow records were taken at periodic intervals from each treatment to determine nutrient concentrations and loads. For all treatments and sites, total nitrogen (TN) and total phosphorus (TP) concentrations were compared to USEPA reference value concentrations in streams of the Xeric West for full support of aquatic life and drinking water standards. Results showed that TN exceeded the USEPA reference condition of 0.36 mg TN per liter in all samples, while 96 percent of the samples exceeded the USEPA recommended TP concentration value of 0.1 mg per liter. All samples showed nitrate concentrations below the USEPA drinking water standard of 10 mg per liter. Although PAM is an excellent practice to control soil erosion with widespread adoption, additional off-site treatment will be needed for reducing nutrient concentrations in irrigation return flows below the strict EPA’s reference conditions that would fully support aquatic life.

Technical Abstract: The objective of this research was to assess soil conservation practices for improving water quality of return flows from rill irrigation in the Yakima River Basin, Washington, by combining patch application of polyacrylamide (PAM) with an additional erosion control practice. A two-year field study was conducted that combined PAM with 1) check dams, 2) surge irrigation, 3) surface drains, and 4) grass filter strips. The study was conducted at three sites: two vineyards (A and B) with silt loam soils at 1.2 percent slope and a cornfield with sandy loam soils at 0.2 percent slope. During irrigation events, water samples and flow records were taken at periodic intervals from each treatment to determine nutrient concentrations and loads [total nitrogen (TN), total Kjeldahl N (TKN), nitrate-N, total phosphorus (TP), particulate P (PP), soluble phosphorus (SP), and sediment load (SL)]. For all treatments and sites, TN and TP concentrations were compared to USEPA reference value concentrations in streams of the Xeric West for full support of aquatic life and drinking water standards. Results showed that TN exceeded the USEPA reference condition of 0.36 mg TN/L in all samples, while 96 percent of the samples exceeded the USEPA recommended TP concentration value of 0.1 mg/L. All samples showed nitrate-N concentrations below the USEPA drinking water standard of 10 mg/L. The only nutrient component in irrigation runoff that was strongly related to SL was PP concentration (r = 0.87). For TKN, significant concentration and load reduction between control and the other four erosion control practices (P < 0.05) occurred only in vineyard A. As for PP, the four PAM integrated control practices showed statistically significant effects with respect to the PAM control in vineyard B only. Although PAM is an excellent practice to control soil erosion with widespread adoption, additional off-site treatment will be needed for nutrient concentrations in irrigation return flows to meet USEPA’s reference conditions that would fully support aquatic life.

Last Modified: 9/2/2014
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