Impact of sequential applications of rain and irrigation into a cropped soil

Authors: Suarez, Donald; Wood, James; LESCH, SCOTT - UNIV. CA - RIVERSIDE

Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2007
Publication Date: 11/1/2007
Citation: Suarez, D.L., Wood, J.D., Lesch, S.M. Impact of sequential applications of rain and irrigation into a cropped soil. American Society of Agronomy Abstracts. Soil Science Society of America Annual Meeting held in New Orleans, LA. November 4-8, 2007. Paper No. 230-18 CD-ROM.

Interpretive Summary:

Technical Abstract: The SAR salinity criteria for irrigation have been developed for conditions where the irrigation water is the only source of water supply. It is not clear that these criteria are applicable to conditions where there are rain and irrigation events during the growing season. The low electrical conductivity of rainfall is expected to result in increased sodicity hazard to soil hydraulic properties. In this study we examine the effects of irrigation waters of SAR 2, 4, 6, 8, and 10 and electrical conductivities of 1 and 2 dS/m on the infiltration rate of two soils in a management system where there are alternating cycles of rain (simulated with a rainfall sprinkler) and irrigation water separated by drying cycles. A sandy loam and silty clay soil were evaluated under cropped conditions of full canopy cover for 200 d. At the end of the experiment undisturbed soil cores were taken for laboratory determination of saturated hydraulic conductivity. Reductions in infiltration in the outdoor container studies were significant for both soils for SAR above 2, indicating high sensitivity to SAR under combined rain irrigation conditions and despite surface soil protection from the alfalfa crop. Sensitivity to SAR was comparable to that determined earlier for these same two soils under uncropped conditions.