Effects of Polyacrylamide on Infiltration of High-Sodium Water
Investigators (most current known information)
Irrigated agriculture is feasible only where supplies of water are available and where physical properties of soils promote plant growth. High-sodium waters, such as wastewaters, typically reduce hydraulic conductivity and infiltration, and contribute to surface crusting. These waters may be adequate for irrigation if management strategies can overcome their harmful effects on soil. Polyacrylamide (PAM) may work better than the gypsum presently used to overcome effects of sodium. In laboratory studies, columns containing 8 cm of various soils were exposed to 4 levels of PAM (0, 10, 25, 40 mg/L) applied in 8 cm of water, then to weekly applications of wastewater or simulated rainwater over a period of 8 weeks. Hydraulic conductivity was measured weekly by the falling head method. For each soil, PAM improved hydraulic conductivity significantly--in some cases very dramatically. Effects were most apparent in the first weeks, and tapered off in subsequent weeks. Repeated applications of PAM improved the persistence of PAM effects. In a field study, PAM was metered into irrigation water at the rate of 25 mg/L, and applied in every or every other irrigation. A gypsum treatment, a non-amended control and a non-irrigated control were also established. Irrigation was supplied as needed during summer months, followed by an unusually rainy period. Surface infiltration rates were measured in late winter at heads and tails of irrigation furrows. PAM significantly (P less than 0.05) increased infiltration rates by a factor or two. Effects of gypsum were noted, but were less significant. PAM has the practical potential to facilitate irrigation with high-sodium wastewaters.
Articles in Journals
Gardiner, D., P. Felker and T. Carr. 1999. "Cactus extract increases water infiltration rates in two soils." Communications in Soil Science and Plant Analysis 30:1707-1712.
Gardiner, D.T. 1996. "Gypsum and polyacrylamide soil amendments used with high sodium wastewater." Texas Water Resources Institute. College Station TX. Technical Report 174, 50.
Levy, G.J., J. Levin and I. Shainberg. 1995. "Polymer effects on runoff and soil erosion from sodic soils." Irrigation Science 16:9-14.
Gardiner, D.T., T.A. Carr and R.N. Morgan. 1999. "Soil water distribution following polyacrylamide application." 294. In Annual Meeting Abstracts, Salt Lake City. American Society of Agronomy, Madison WI.
Gardiner, D., Q. Sun, E. Mendez and T. Carr. 1998. "Improving water infiltration and ameliorating soil crusting with polyacrylamide." In Tropical hydrology and Caribbean water resources, ed. R.I. Segarra-Garcia, 167-172. American Water Resources Association.
Gardiner, D.T. and T. Carr. 1998. "Polyacrylamide application affects soil moisture distribution." In Annual Meeting Abstracts, Baltimore, 272. American Society of Agronomy, Madison WI.
Gardiner, D.T., B.E. Mendez and Q. Sun. 1997. "Polyacrylamide to control harmful effects of irrigation with wastewater." In Agronomy Abstracts, Anaheim CA. American Society of Agronomy, 267. Madison WI.
Gardiner, D.T. and B.E. Mendez. 1995. "Effects of polyacrylamide on infiltration of wastewater." In Proceedings of the 24th Water for Texas Conference, 245-250. 16-27 Jan. Austin TX.