Integrated on-farm drainage management for drainage water disposal

Abstract

Providing environmentally safe methods for disposal of drainage water containing salt and nutrients is a challenge for irrigated agriculture. A system developed for sequentially using saline drainage water for supplemental irrigation resulted in significant reduction of the drainage water volume. This system dubbed integrated on-farm drainage management' (IFDM) was demonstrated on four 65-ha fields located on a farm on the west side of the San Joaquin Valley of California. Three of the fields were used to grow salt-sensitive crops (tomato, garlic) and the fourth was used to grow salt-tolerant crops, e.g. Jose' tall wheatgrass. Subsurface drainage systems were installed on all fields at a maximum depth of 1.8m and had controls to regulate shallow water table position and drainage flow. The total drainage flow from the site represented 0.7% of the applied water. The area used for salt-tolerant crops was less than 6% of the total area served, compared to using evaporation ponds requiring areas equal to or greater than 10% of the served area. The results demonstrated that the regional groundwater quality masked the concentrating effect of crop water use. Deep percolation from the fields contributing to the reuse area ranged from 6 to 10% of the total applied water. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.