Alfalfa for Hydrologic Control of Saline Seeps1
- A. D. Halvorson and
- C. A. Reule2
Saline seeps affect extensive dry cropland areas in the northern Great Plains and methods need to be devised to control them. The effectiveness of alfalfa (Medicago sativa L.) in controlling saline seepage on northern Great Plains small grain dryland farms was studied from 1971 to 1977.
Alfalfa, when grown on about 80% of the recharge area, reduced the deep percolation of soil water and provided hydrologic control for two seep areas within 1 year after its establishment in recharge areas. As the perched water table receded, the soil surface in the discharge (seepage) area dried allowing passage of farm implements, soil salinity decreased, and weeds, grasses, and crops grew better in the seepage area.
In contrast, a buffer strip of alfalfa (occupying about 20% of recharge area) on the upslope side of a saline seep did not provide hydrologic control. Greenhouse data indicated that alfalfa yields will decrease rapidly if soil salinity increases to high levels above a saline water table. Reduced plant growth resulted when salts accumulated in the root zone as water moved upward by capillary action. When in situ root zone soil salinity reached an EC of 38 mmho/cm, alfalfa growth essentially ceased.
We concluded that alfalfa can effectively control the hydrology of saline seep areas if it is grown on a major portion of the recharge area.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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