Nutrient Management Research Database

Use of subsurface drip irrigation (SDI) has progressed from being a novelty employed by researchers to an accepted method of irrigation of both perennial and annual crops. This paper reviews the SDI research conducted by scientists at the Water Management Research Laboratory over a period of 15 years. Data are presented for irrigation and fertilization management on tomato, cotton, sweet corn, alfalfa, and cantaloupe for both plot and field applications. Results from these studies demonstrated significant yield and water use efficiency increases in all crops. Use of high frequency irrigation resulted in reduced deep percolation and increased use of water from shallow ground water when crops were grown in high water table areas. Uniformity studies demonstrated that after 9 years of operation SDI uniformity was as good as at the time of installation if management procedures were followed to prevent root intrusion. Published by Elsevier Science
B.V.

• Plot studies were conducted at the California State University, Fresno and the University of California West Side Research in Fresno and Extension Center, and at the USDA-ARS Irrigated Desert Research Station in Imperial Valley as well as on-farm field studies in Mendota .
• This article comprised a review of several experiments over many years.
• Experiments focused on water management, irrigation scheduling, fertilizer use and crop quality or productivity in relation to subsurface drip irrigation (SDI).

• At California State University, Fresno, SDI plots produced more marketable tomatoes than furrow-irrigated tomatoes.
• In general, a dramatic increase of yields were found in tomatoes, corn and cantaloupes with SDI due to improved water and fertilizer management
• Tomato quality was significantly higher in treatment 2, irrigated once every six days and twice per day, and treatment 8, irrigated multiple times per day, but less than 6.
• The use of SDI eliminated surface sealing which occured in furrow irrigated plots.
• At West side field station, SDI treatments produced greater red tomato yields than either high or low frequency surface irrigation.
• Maximum yields occurred with P fertilizer injected at a level of 67kg/ha.
• For Canaloupes the number of ground-spotted and rotten cantaloupes was lowest with SDI when compared to high or low frequency irrigation, although growth cracks were more prevalent with SDI and yield was not significantly affected.
• For all crops, SDI demonstrated potential for increasing water use efficiency and minimizing deep percolation.
• At the USDA-ARS Irrigated Desert Research Station, Alfalfa yield for SDI plots was 26-35% higher in 1994-1995 than furrow plots.
• In the field study in Mendota, CA, Cotton yields improved in drip-irrigated plots over the 3 year study, while furrow yields remained constant.

Depth of placement of SDI was not studied, but research suggested that a depth of 45cm was routinely used for the lateral depth placement and was very successful. In all cases the SDI system was not used for the germination of the crop and pre-plant irrigation was conducted to leach salts and refill the root zone.