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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #148087
Title: PAM AND STRAW RESIDUE EFFECTS ON IRRIGATION FURROW EROSION AND INFILTRATION

Author
item Lentz, Rodrick
item Bjorneberg, David - Dave

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2003
Publication Date: 12/1/2003
Citation: Lentz, R.D., Bjorneberg, D.L. 2003. Pam and straw residue effects on irrigation furrow erosion and infiltration. Journal of Soil and Water Conservation. 58(5):312-319.

Interpretive Summary: The presence of plant residues in irrigation furrows is beneficial because it reduces furrow stream velocity and increases the breadth and depth of the flow. This reduces soil erosion and increases water infiltration. However, farmers commonly clean till their furrow irrigated fields because residue left in furrows becomes detached and is transported down-furrow by the water stream, where it is collects in deposits that block the furrow. This results in flooding and poor irrigation uniformity. This study shows how a small application of polyacrylamide (PAM) to furrows containing plant residue produces erosion-controlling and infiltration-enhancing benefits that exceed those produced when PAM or residue are used alone. The PAM also stabilizes the plant residues in the furrows, preventing them from moving downstream, forming dams, and causing flooding. This study demonstrates how PAM and irrigation practices can be used to alleviate problems caused when farmers attempt to use conservation tillage on furrow irrigated fields. This management can potentially reduce production costs by eliminating the time and expense associated with the additional tillage operations needed to plow-down plant residues in furrow irrigated fields.

Technical Abstract: Water soluble anionic polyacrylamide (PAM) is a highly effective erosion deterrent in furrow irrigation. We hypothesized that increasing plant residue in irrigation furrows may alter PAM's ability to control erosion. Treatments included furrows with 10 g/m (485 kg/ha on treated area) and 30 g/m (1490 kg/ha) wheat straw applications with or without PAM (33 g/furrow or 1 kg ai/ha as granular patch), and conventionally irrigated furrows (no PAM and no straw). Five irrigations were monitored on a field with 1.5% slope and silt loam soil (Durinodic Xeric Haplocalcids). Compared to controls, individual straw and PAM+straw treatments reduced sediment loss in all irrigations by 64 to 100%, but increased infiltration (1.3x to 2.5x) only for irrigation one, when furrows were fresh. Adding more straw to low-straw (with or without PAM) treatments increased average sediment loss reduction from 86 to 94% in the first two irrigations, but provided no extra benefit in subsequent irrigations (relative to controls). Adding PAM to low- and high-straw treatments increased average sediment loss reduction from 80 to 100% in the first two irrigations, and from 94 to 99.8% in subsequent irrigations. Combining plant residue and PAM in furrows produced greater erosion control and larger infiltration enhancements than with straw alone. An important additional benefit of PAM is that it greatly reduced detachment, transport, and redistribution of residue in furrows, which helped prevent furrow blockage and attendant overflow problems, and allows farmers to use conservation tillage in furrow irrigated fields.