Subirrigation with brackish water for vegetable production in arid regions

Brackish water is the principal source of irrigation water in many arid reg ions. Surface irrigation with brackish waters is limited to salt tolerant c rops or is used alternately with scarce freshwater resources. However, subi rrigation may help overcome some of the limitations associated with the use of brackish water in arid agricultural regions. Use of this technique to p roduce potatoes (Solanum tuberosum? L.), one of the world's major food crop s, is investigated in this study. The yield and tuber grade of 'Atlantic' a nd 'Russet Burbank' potatoes were evaluated in field lysimeters packed with a sandy soil, salinized to 3.5 dS/m, and then subirrigated with water havi ng salinity levels (ECi) of 1, 5 or 9 dS/m, beginning 13 days after plantin g. Preventing rainwater entry by using plastic mulch simulated arid conditi ons. Water tables were maintained at 40 or 80 cm below the soil surface. At harvest, soil solution salinity (ECw) in the lysimeters ranged from 3.5 to 7.6 dS/m. Water table depths or subirrigation water salinity levels had no significant effect on the total tuber weight of either cultivar. However, yield of grade A Russet Burbank tubers was greater when the water table was maintained at 40 cm. This trend was similar but not significant for Atlant ic tubers. Productivity of Atlantic was lower than that of Russet Burbank. Subirrigation with brackish water in the saline soil resulted in yield that was 59% above the global average, thus demonstrating its utility for agric ulture in dry regions. (C) 1999 Elsevier Science Ltd. All rights reserved.