M. Magaritz - The Weizmann Institute of Science, Rehovot, Israel
Extensive agricultural activity often increases the salt load of the unsaturated zone. The focus of the study was a field investigation of the effects of saline‐water irrigation and gypsum addition in a semiarid region with loessial soils, where intensive evaporation conditions prevail. Using drilling (∼20 m) to obtain sedimentary deposit samples, it was shown that most of the salts added by agricultural activity accumulate in the unsaturated profile. Seventy to ninety percent of SO4−2, Na+, and Cl− added are retained in the upper 2–4 meters of the profile after 6 to 12 years of cultivation, regardless of the soil type. The most common accumulating ions are Na+ and SO4−2 that minimize gypsum amendment thereby increasing with time the danger of an irreversible loss of the loessial soil as productive land.
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