Sprinkler Irrigation Runoff and Erosion Control with Polyacrylamide — Laboratory Tests

Abstract

Many semiarid and arid soils are prone to irrigation-induced erosion. Polyacrylamide (PAM) greatly reduces erosion from furrow irrigation. We hypothesized that PAM applied via sprinklers will provide erosion control and benefit water infiltration and aggregate stability. Screened (6.4 mm) Rad silt loam (coarse silty, mixed, superactive mesic Durinodic Xeric Haplocambid) was placed in 1.5 by 1.2 by 0.2 m steel boxes with 2.4% slope. An oscillating nozzle, 3 m above the soil, produced a median drop size of 1.2 mm diameter. We applied 0, 1, 2, 4, and 6 kg ha' PAM in 20 mm of water in the first irrigation, followed by two 20-mm water-only irrigations. In a second test, we applied 0, 2, and 4 kg ha ' PAM in 8 mm of water in the first irrigation, followed by two 20-mm water-only irrigations. Two kilograms per hectare PAM in the first 20-mm irrigation reduced runoff 70% and soil loss 75% compared to control. Polyacrylamide in 8 mm of water was less effective. Polyacrylamide in the 20-mm irrigation did not affect tension infiltration; PAM in the 8-mm irrigation doubled tension infiltration following the third irrigation. Wet aggregate stability following the first irrigation was greater in all PAM treatments than on the check. With 2 kg ha" PAM in the 20-mm irrigation, it was 55%; in 8 mm, 77%. Polyacrylamide applied in the first irrigation at low rates effectively reduced runoff and erosion. Erosion was more effectively controlled than runoff.

Affectability of splash erosion by polyacrylamide application and rainfall intensity

“…We can understand from the results of this research that for controlling soil erosion in marly soils, there is a need to use a considerable amount of PAM, because soil winds have a high potential in generating sediments and also as it was mentioned in research, the rate of 0.4 g/m 2 of PAM has the highest effect on reducing the erosion rate in soils. The result of this study has a great accordance with the results obtained by Sepaskhah and Bazrafshan-Jahromi (2006) and Aase et al (1998). We concluded from results that PAM reduces erosion and it mainly reduces the initial stage of erosion, i.e.…”

Controlling Sprinkler Irrigation Runoff, Erosion, and Phosphorus Loss With Straw and Polyacrylamide

“…Applying 3 to 12 kg PAM ha-1 with simulated rainfall can also reduce runoff and erosion (Ben-Hur et al, 1989;Levy et al, 1992). During the initial irrigation in a laboratory simulation, applying 2 to 4 kg PAM ha-1 with 20 mm of water reduced runoff 70% and soil loss 75% compared to untreated soil (Aase et al, 1998). However, after two subsequent irrigations with only water, runoff was similar between untreated and PAM-treated soil.…”

Technologies to Minimize Water Quality Impacts of Irrigated Agriculture

“…In situations where tillage, management and system design do not adequately control sprinkler irrigation runoff, PAM can be used to improve infiltration. Laboratory tests showed that applying 2 to 4 kg/ha PAM with 20 mm irrigation on 1.9 m2 soil boxes, reduced runoff by 70% and soil loss by 75% compared to untreated soil (Aase et al, 1998). Applying PAM with multiple irrigations was more effective than applying the same total mass of PAM with a single irrigation in both laboratory (Bjorneberg and Aase, 2000) and field tests .…”