Submitted to: International Conference on Water Resources Engineering Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 9, 1999
Publication Date: N/A
Interpretive Summary: We determined the ability of PAM-treatment of furrow irrigation water applied to an agricultural field to remove several categories of microorganism from the inflow and runoff. Treatments were 1) PAM application and a control, 2) flow rate, 3) distance from the inflow point, and 4) time during irrigation. At 1 meter below the inflow point, at 15.5 liter/m , PAM-treatment reduced active and total bacterial and microbial biomass, total fungal biomass, and the total fungal/total bacterial ratio (TF/TB) relative to the control treatment. At 40 meters below the inflow point, at 7.5, 15.0, and 22.5 liter/min, PAM-treatment reduced algae, active and total bacterial biomass, total fungal and microbial biomass, (TF/TB) compared to the control treatment. Flowing water can carry various soilborne plant pathogens, such as Phytophthora spp., Pythium spp., Fusarium spp and Polymyxa spp. Limiting the movement of plant pathogens in water might have a positive impact on control of plant diseases caused by these pathogens. Apart from furrow irrigated crop agriculture, new ways to manage overland movement of harmful microorganisms in surface waters might also be used to control transmission of pathogens from animal waste in runoff and ground water.
Technical Abstract: Polyacrylamide (PAM) use in irrigation for erosion control has increased water infiltration and reduced soil erosion. Since non-toxic high molecular weight anionic PAMs removed clay size sediment particles in flowing water, we hypothesized that PAM would effectively remove or immobilize microorganisms in flowing water. In an agricultural field, we determined the efficacy of PAM-treatment of furrow irrigation water to remove several categories of microorganisms in the inflow and runoff. Treatments were 1) PAM application and a control, 2) three flow rates, 3) two distances from the inflow point, and 4) three times during each irrigation. After water traveled 1 meter at 7.5 and 15.5 liter/min, PAM-treatment reduced total bacterial and microbial biomass and total fungal biomass relative to the control treatment. After water traveled 40 meters at 7.5, 15.5, and 22.5 liter/min, PAM-treatment reduced algae, the numbers active and total bacteria, active and total fungal length, and total bacterial biomass, total fungal and microbial biomass relative to the control treatment.