Water Harvesting for Olive (Olea europaea L.) Trees in a Marginal Dry Area of Northwestern Syria

Abstract

Olive production in marginal dry areas requires careful soil, water, and nutrient management. Farmers in the Khanasser Valley, Syria, developed their own water-harvesting technique by combining V-shaped bunds with up- and down-slope tillage furrows after examination of the semi-circular structures in a no-till water harvesting research site. The farmers cooperated with the researchers to investigate the effects of their new water harvesting technique in this dry environment (220 mm annual rainfall). Soil moisture content was monitored weekly during the first half of 2004. A control treatment without water harvesting structures was also monitored. Throughout the rainy season, soil moisture content in the rootzone of the trees with water harvesting structures was 4 to 15% higher than in the control. Almost all water gained by water harvesting was stored in the layers below 40-cm depth. This study showed that little labor investments by farmers can provide critical extra water needs to olive trees in dry, sloping lands.