Surface irrigation with saline water on a heavy clay soil in the Medjerda Valley, Tunisia.

Abstract

On a clay soil rich in lime, with drain spacings of 30 and 60 m, one section (A) after four crops of artichokes over a two-year period, with fairly intensive irrigation with saline water (approx 700 mm annually) showed no harmful salinity effects; in the upper 120 cm the electrical conductivity of soil extracts (EC) seldom exceeded five. On section B, with well-distributed irrigation, which was not intensive except for tomatoes in one summer, salinity was fairly uniform in the profile (EC 4-6). In section C, under continuous lucerne and with 1000-1200 mm water annually, salinity increased, especially with depth, and a fallow period was needed. In section D, under four artichoke crops followed by maize, with more intensive irrigation than in A and B, EC of the 80-120 cm layer was 7-8, and maize growth was retarded slightly. In addition to fallowing, the inclusion in rotations of winter crops and of perennials with a resting period in summer, e.g. artichokes, is recommended. A drain spacing of 60 m was adequate. (Abstract retrieved from CAB Abstracts by CABI’s permission)