The use of PAM -- a linear polyacrylamide for use in irrigation water

Uso de PAM -- un poliacrilamido linear para el uso en agua de irrigación

Sojka, R.E. (2002) The use of PAM -- a linear polyacrylamide for use in irrigation water. In: Proc. National Alliance of Independent Crop Consultants 2001 Annual Meeting. Available: http://www.NAICC.org/

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Abstract

This overview will be familiar to anyone who has visited the "PAM page" of the Northwest Irrigation and Soils
Research Laboratory's web site. The reader is encouraged to visit that web site,
<http://kimberlv.ars.usda.qov/ pampaqe.shtml>, for graphics and photos that were used in this NAICC presentation in
Orlando in January, 2001, as well as for other more detailed technical information.
PAM has been sold in the United States since 1995 for reducing irrigation-induced erosion and enhancing
infiltration. Its soil stabilizing and flocculating properties have also substantially improved runoff water quality by
reducing sediments, N, ortho and total P, COD, pesticides, weed seeds, and microorganisms in runoff. The first
series of practical field tests of PAM for irrigation erosion control was conducted in the U.S. in 1991. PAM used for
erosion control is a large (12-15 megagrams per mole) water soluble (non-crosslinked) anionic molecule, containing
<0.05% acrylamide monomer. In a series of field studies, PAM eliminated an average 94% (80-99% range) of
sediment loss in field runoff from furrow irrigation, with 15-50% relative infiltration increases compared to untreated
controls on medium to fine textured soils. Similar but less dramatic results have been seen with sprinkler irrigation.
In sandy soils infiltration is often unchanged by PAM or can even be slightly reduced. Results are achieved with per
irrigation field PAM application rates of about 1 kg ha-1 for furrow irrigation and about 4 kg ha-1 for sprinkler
irrigation. Often only fractions of these rates are required on subsequent irrigations (if the ground has not been
disturbed between irrigations) to maintain efficacy. Typical seasonal application totals vary from 3 to 7 kg per
hectare. Farmer field sediment control has generally been about 80% or more of test plot results.
Research has shown no adverse effects on soil microbial populations. PAM effects on crop yields have only been
sparsely documented. Initial studies, focused mostly on erosion and runoff water quality effects, conducted largely in
field beans or maize, showed little effect on yields, probably because all treatments were supplied adequate water.
Some evidence exists for PAM-related yield increases where infiltration was crop-limiting, especially in field portions
having irregular slopes, where erosion prevention eliminated deep furrow cutting that deprives shallow roots of
adequate water delivery. PAM's ability to increase lateral spread of water during infiltration is useful for early season
water conservation. Only small amounts of water are needed to germinate seed or sustain small seedlings shortly
after planting. Water conservation is accomplished by not needing to completely fill the soil profile because wetting
patterns of PAM-treated furrows spread further laterally for a given volume of water applied. High effectiveness and
low cost of PAM for erosion control and infiltration management, coupled with relative ease of application compared
to traditional conservation measures, has resulted in rapid technology acceptance in the US, with about 400,000 ha
of irrigated land currently employing PAM for erosion and/or infiltration management.
Water soluble anionic high-purity PAM is a safe environmentally friendly soil conditioner, that when delivered via
irrigation, reduces erosion, prevents sediment and chemical and biological pollutants from entering runoff and greatly
expands management options for all forms of irrigated agriculture because of its soil stabilizing effects and direct
effects on water properties influencing field water management. PAM is economical, typically $4.50 to $12 per
kilogram of active ingredient, effective at low rates (1 to 5 kg per hectare per season) and relatively easy to use.

Item Type:	Conference or Workshop Item (Paper)
NWISRL Publication Number:	1075
Subjects:	Polyacrylamide (PAM) > Water-soluble PAM (WSPAM) Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:58
Last Modified:	24 Oct 2016 15:31
Item ID:	1235
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/1235