Using Reclaimed Water for Irrigation.

Using Reclaimed Water for Irrigation

J. Escalera, D. Jenkins, and C. Amrhein

University of California, Riverside

 Drought and water shortages are becoming an unavoidable crisis in arid regions.  As a result, cities are considering switching agricultural irrigation over to reclaimed water to free up good quality ground water for municipal uses. However, reclaimed water can decrease hydraulic conductivity in the soil because it contains a high concentration of dissolved salts and sodium.  Sodium reduces hydraulic conductivity by swelling and dispersing clay particles in the soil thus reducing the water-conducting pores. Reduced water infiltration may cause ponding, root rot and damage to crops.  Furthermore, high concentration of boron found in recycled water can lead to toxicity in plants like citrus.  The purpose of these laboratory experiments was to determine the effect of reclaimed water on hydraulic conductivity and changes to the boron concentration in soils cropped to citrus. Results show that reclaimed water can significantly decrease hydraulic conductivity on soils found in Riverside orange orchards.  Soils with horizons of clay accumulation showed a greater reduction in hydraulic conductivity and higher boron adsorption. This suggests that farmers might have to change their irrigation practices if they are forced to use reclaimed water for irrigation.