Irrigating with polyacrylamide (pam) - nine years and a million acres of experience

摘要

Polyacrylamide (PAM) has been available commercially since 1995 for reducing irrigation-induced erosion and enhancing infiltration. The first series of practical field tests was conducted in 1991. PAM used for erosion control is a large water soluble (non-crosslinked) anionic molecule (12-15 megagrams per mole) containing < 0.05 percent acrylamide monomer. In controlled field studies PAM eliminated, on average, 94 percent (80-99 percent range) of sediment loss in field runofF from furrow irrigation, with atypical 15-50 percent relative infiltration increase on medium to finen textured soils compared to untreated controls. Similar but less dramatic results have been seen with sprinkler irrigation. Under some conditions infiltration is unchanged orcan even be slightly reduced, e.g. in sandy soils or where PAM application rates are very high. Results are achieved with per irrigation field application rates of about 1 kg per hectare, for furrow irrigation, and 2 to 4 kg per hectare for sprinkler irrigation. Cost of PAM is 7 dollar to 13 dollar per kg. Seasonal application 'totals vary from 3 to 7 kg per hectare. Farmer field sediment control has been around 80 percent of test plot results. Substantial runoff reductions have been documented for nutrients, pesticides, microorganisms, BOD, and weed seed. No adverse effects have been seen for soil microbial' populations. Crop yields have not been widely documented, though evidence exists for yield increases related to infiltration improvement. Higheffectiveness, low cost, and ease of application, compared to traditional conservation measures, has resulted in rapid technology acceptance in the US and internationally. PAM-use for runoff water quality protection is one of the most potent new irrigation environmental technologies in the market place. New uses in construction and dryland erosion control are being developed rapidly. This paper discusses new insights and understanding of PAM-use and potential for future developments.