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Effects of Irrigation Management on the Quality of Irrigation Return Flow in Ashley Valley, Utah
Author(s) -
Bliesner Ron D.,
Hanks R. J.,
King L. G.,
Willardson L. S.
Publication year - 1977
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1977.03615995004100020051x
Subject(s) - leaching (pedology) , irrigation , environmental science , lysimeter , salinity , hydrology (agriculture) , leaching model , soil salinity , return flow , soil water , precipitation , soil science , agronomy , geology , flow (mathematics) , mathematics , geography , oceanography , geotechnical engineering , geometry , meteorology , biology
The relationship between leaching fractions obtained under field conditions and soil water salinity profiles on nature alfalfa was studied by applying three qualities of water at three leaching fractions to areas of an alfalfa field ( Medicago sativa L.) having three depths to water table. The electrical conductivity of the irrigation water and of the soil solution extract at various depths was measured for each irrigation. ET measurements from several lysimeters located in the field were used to determine depths of irrigation water to apply. A sprinkler irrigation system was used for application of the irrigation water to the plots, and the depth applied was determined by measuring the depth of water caught in cans placed in a sample plot during each irrigation. The electrical conductivity of the irrigation waters applied averaged 0.98 mmhos/cm, 2.22 mmhos/cm, and 2.80 mmhos/cm for the season. Leaching fractions for the low leaching treatment of each water quality averaged 0.003. The other leaching treatments ranged from 0.082 to 0.343. Assuming an inert soil with no precipitation or dissolving of salts, there should have been increases in average soil profile salinity ranging from 1.81 mmhos/cm to 5.45 mmhos/cm during the season depending on the treatment. The largest increase measured on any treatment was 0.32 mmhos/cm. Some treatments actually caused a decrease in salinity where an increase was expected. For the condition of this study it appears that soil profile salinity is relatively insensitive to leaching fraction for short periods of time (1 or 2 years). This is attributed to the high relative concentrations of calcium and sulfate in the irrigation water and soil solution. Bearing these factors in mind, it appears that the quantity of salt removed in the drainage water varies directly with the quantity of drainage water since the concentration is relatively constant.