Polymer charge and molecular weight effects on treated irrigation furrow processes

EFECTOS DE LA CARGA DEL POLIMERO Y EL PESO MOLECULAR EN PROCESOS DE SURCOS TRATADOS DE irrigación

Lentz, R.D. and Sojka, R.E. and Ross, C.W. (2000) Polymer charge and molecular weight effects on treated irrigation furrow processes. International Journal of Sediment Research. 15(1):17-30.

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Abstract

Application of 5-10 mg L-1 water soluble anionic polyacrylamide (PAM) to furrow irrigation water
during flow advance substantially reduces sediment loss and increases net infiltration. We hypothesized
that PAM_s solvated molecular conformation influences its irrigation-management efficacy. The study
was conducted in Kimberly, Idaho, on Portneuf silt loam (Durinodic Xeric Haplocalcids); under furrow-
irrigated beans (Phaseolus vulgaris ) at a 1.5% slope. Polyacrylamides with contrasting molecular
weight (anionic: 4-7, 12-15 and 14-17 MDa, i.e. Mg mol -1 ), charge type (neutral, anionic, cationic), and
charge density (8, 19, 35 mol %) were tested in two studies. Inflow rate was 23 L min d during furrow
advance, and 15 L min-1 for the remaining set. Anionic and neutral PAMs were twice as effective as
cationic PAMs for controlling sediment loss in new furrows. The order of effectiveness for overall soilloss
control was: anionic > neutral > cationic PAM, and efficacy increased with increasing charge density
and/or molecular weight. Net furrow infiltration increased by 14 to 19% when PAM treatment molecular
weight was reduced from 17 to 4 MDa. General trends suggested that medium and high charge density
anionic and neutral PAM produced the greatest increase in infiltration compared with controls.
Compared with untreated furrows, neutral PAM gave the greatest season-long net infiltration gains (5%);
while charged PAMs tended to increase net infiltration early in the season on new furrows but decreased
infiltration on repeat-irrigated furrows later in the season.

Item Type:	Article
NWISRL Publication Number:	1023
Subjects:	Mass Import - unclassified
Depositing User:	Users 6 not found.
Date Deposited:	20 Nov 2010 21:50
Last Modified:	14 Nov 2016 19:03
Item ID:	111
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/111