On-farm rainfall harvesting in drylands of Jordan

Abstract

Rainfall harvesting in arid regions and semi-arid regions increases soil water availability for plant during the growing season, thus increasing crop production. Jordan is facing the most serious water shortages in the Middle East. It is an arid country located east of the Jordan River with a land area of about 90,000-km. Contour stone terraces have been widely used by Jordanian farmers in the hilly areas for soil and water conservation purposes. Traditionally, farms’ soil is subjected to systematic deep plowing to break up the surface rocks and then remove stones for installation of stone terraces. A new land reclamation method for water harvesting has been experimented in the hilly parts of Jordan that improves the effectiveness of traditional stone terraces. The method consists of designing semi-circular stone bunds randomly based on the micro topography of land. Semi-circular bunds were located at areas having deep soil pockets and adequate runoff rocky area and do not require deep plowing with minimum land disturbance. This method minimizes soil erosion, maximizes rainfall harvesting due to the high runoff efficiency from runoff rocky areas, and promotes biodiversity. The cost of this method is about 85% less than that of the traditional stone terraces used by Jordanian farmers. Field evaluations showed that semi-circular bunds increased soil moisture and Sage yield in the cropping areas by about 7% and 35% compared to control areas, respectively. The soil depth in some of the cropping terraced areas increased by about 3 and 25 cm at the end of the 2003/2004 and 2016/2017 rainy seasons, respectively.