Copyright August 1997, all rights reserved The study is being conducted in a Thompson Seedless vineyard located on the Califomia State University, Fresno, farm laboratory. The vines were planted in 1980, and are spaced 7 feet by 12 feet. New drip irrigation tubing was installed prior to the start of the 1996 season. Netafim Ram, pressure compensating inline emitters spaced at 42 inches, deliver 0.4 gallons per hour per emitter, or 0.8 gallons per hour per vine.
Treatments consist of surface applied gypsum, drip injected gypsum, and control with no treatment.
In the surface applied gypsum treated areas, 1.15 pounds of gypsum was applied by hand directly below each ermitter. The drip injected gypsum treatment area received gypsum directly into the irrigation water with a skid mounted tank and pump provided by Soil Solutions Corporation. The solution grade gypsum is injected daily at a rate of 640 pounds per acre-foot of irrigation water. Irrigations and gypsum were applied on a daily basis. Data collected includes yield, fruit composition, petiole nutrient content, pruning weights, and infiltration rate of the soil.