Polymers check furrow erosion, help river life
Hal McCutchan, UC Cooperative Extension
Phil Osterli, Stanislaus County
John Letey, UC Riverside
California Agriculture 47(5):10-11.
Each year, irrigation runoff from West Stanislaus County farmland carries about 1.2 million tons of sediment into the San Joaquin River. The sediment contains pesticide residues which threaten aquatic wildlife. One solution for this problem is to inject polyacrylamide polymers into irrigation water, a practice which reduces soil erosion and has economic benefits to the grower, such as increasing infiltration rates. In recent trials, this practice reduced soil erosion and runoff water from a furrow-irrigated spinach field. Polyacrylamide-treated furrows had a 10% lower outflow rate than the untreated furrows. In addition, the polyacrylamide flocculated the suspended soil particles; on average, 99.7% settled out compared to soil particles in untreated furrows.
H. T. McCutchan is a Postgraduate Researcher, UC Cooperative Extension, Stanislaus County; P. P. Osterli is County Director and Farm Advisor, Stanislaus County; J. Letey is Professor of Soil Physics, Department of Soil and Environmental Sciences, UC Riverside;
The authors would like to acknowledge Gary Mall of Orestimba Ranches for his assistance; Allied Colloids, Inc. for providing the polymer and equipment; and laboratory and field support from Laboratory Technician Neil Iacklin and Field Assistant Ray Hill, both of UC Cooperative Extension.