CULTIVATION SANDY SOILS USING SUBSURFACE WATER RETENTION TECHNOLOGY (SWRT) UNDER DROUGHTS AND WATER SCARCITY IN IRAQ

A study was carried out to assess the impact of using SWRT on irrigation water use efficient IWUE and yields of chili pepper. Experiments were performed by planting chili pepper in greenhouses during the spring of 2015 at Najaf Province. Soils of location are classified as sandy loam texture. The experiments included four treatments: SWRT, organic matter, tillage and notillage farming and the design was randomized complete blocked design RCBD with four replications. Irrigation scheduling was performed according to soil moisture content as 35% of available water was depleted then irrigation water was added from subsurface drip system to bring soil moisture content back to field capacity. Soil sensors GS3 from the Decagon Devices, USA were used to measure volumetric water content. The results showed the use of SWRT technology leads to saving 22% and 36% of the amount of irrigation water added to the pepper crop compared to the organic matter treatment and the tillage (Control) and no tillage treatments. Increasing the productivity of the agricultural unit in SWRT with improved quality of fruits, the increase percentage of pepper 13%, 8% and 20% compared to the treatment tillage, organic matter and no tillage treatments, respectively. The decrease in the amount of irrigation water added leads to an increase in water use efficiency in SWRT 78%, 38% and 89% compared with control treatment, organic matter and no tillage treatments, respectively.