Water harvesting for reclaiming alkali soils

Abstract

Alkali soils give a considerable amount of runoff during the monsoon and hence provide excellent opportunities for rainwater harvesting. This paper presents a rainwater harvesting technique in which alkali plots are divided into two compartments: the upper compartment is for rainwater harvesting and in the lower one alkali-tolerant grasses are grown. Results of a 4-year study show that a water harvesting compartment at least twice as large as the grassed compartment can provide sufficient rainwater for growing grasses. The pH value of the soil decreased from 10.6 to 9.0 in the 0-15 cm soil layer and in the lower layers to about 9.6. This proposed method of reclamation offers good possibilities for poor farmers, who cannot afford to install tubewells and purchase gypsum. This technique not only reclaims the land but also decreases the runoff from alkaline areas and thus reduces downstream problems. © 1986.