In the past decade, 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 mg L-1 - 10 mg L-1 , i.e., 1 ppm- 10 ppm.[1-9] 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
irrigation water in the first several hours of irrigation
implies a significant costs savings over traditional
application methods, in which hundreds of kilograms per
hectare of soil additives are tilled into the entire (15 cm
deep) soil surface layer. By adding PAM to the irrigation
water, soil structure is improved in the important 1-5 mm
thick layer at the soil/water interface of the 25%-30% of
field surface contacted by flowing water.
In 1995, the U.S. Natural Resource Conservation
Service (NRCS) published a PAM-use conservation
practice standard for PAM-use in irrigation water." 01 A
3-year study[21 applying these standards showed that PAM
at dosage rates of 1 kg ha-1 -2 kg ha-1 per irrigation
eliminated 94% (80%-99% range) of sediment loss in
furrow irrigation runoff, while increasing infiltration
15%-50%. Seasonal application rates using the NRCS
standard typically total 3 kg ha -1 -5 kg ha-1 .
As PAM-use is one of the most effective and
economical technologies for reducing soil-runoff, it has
branched into stabilization of construction sites and road
cuts, with formal statewide application standards set in
Wisconsin and several southern states. Recent studies with
biopolymers such as charged polysaccharides,[11-143
whey," 51 and industrial cellulose derivatives[11.141 introduce
potential biopolymer alternatives to PAM
