Effect of subsurface drip irrigation on processing tomato yield, water table depth, soil salinity, and profitability

The potential of subsurface drip irrigation of processing tomatoes to reduce subsurface drainage, control soil salinity, and increase farm profits in areas affected by saline, shallow ground water was evaluated at three fields with fine-textured, salt-affected soil along the west side of the San Joaquin Valley of California. No subsurface drainage systems were installed in these fields. Yield and quality of tomato of the drip systems were compared with sprinkler irrigation. Yield increases of 12.90–22.62 Mg/ha were found for the drip systems compared to the sprinkler systems with similar amounts of applied water. Soluble solids of the drip-irrigated tomatoes were acceptable. Response of water table levels during drip irrigation showed that properly managed drip systems could reduce percolation below the root zone. Yields of the drip systems were similar over the range of soil salinity levels that occurred near the drip lines. Profits under drip irrigation were 867 to $ 1493 ha−1 more compared to sprinkler irrigation, depending on the amount of yield increase and the interest rate used in the economic analysis.