Polymer additives in irrigation water to reduce erosion and better manage water infiltration

Water-soluble polyacrylamide (PAM) was identified as an environmentally safe and highly effective erosion preventing and infiltration-enhancing polymer when applied in furrow irrigation water at 1-10 g m(-3), i.e. 1-10 ppm. The agricultural use of polyacrylamide, PAM, as an additive in irrigation water has grown rapidly since commercial introduction in 1995 because it improves water infiltration and reduces erosion-induced soil losses up to 97%, saving tons of topsoil per hectare per year Various polymers and biopolymers have long been recognized as viable soil conditioners because they stabilize soil surface structure and pore continuity. The new strategy of adding the conditioner, high molecular weight anionic PAM, to the irrigation water in the first several hours of irrigation enables a significant costs savings over traditional application methods of tilling soil conditoner into the entire (15 cm deep) soil surface layer By adding PAM to the irrigation water soil structure is improved in the all-important 1-5 mm thick layer at the soil/water interface of the 25 to 30% of field surface contacted by flowing water Recent studies with biopolymers such as chitosan, charged polysaccharides, whey, and industrial cellulose derivatives show potential as biopolymer alternatives to PAM. Their success will depend on production economics.