Design & Treatments
These studies were conducted at the USDA Agricultural Research Service George E. Brown Salinity Laboratory in Riverside, California, in outdoor sand tanks. he tank dimensions were: 82 cm in length, 202 cm in width and 84 cm in depth, were filled with coarse sand. Budded 2-yr old pistachio trees (P. vera scion on the three rootstocks) were obtained from a commercial nursery. Three trees, one of each scion/rootstock combination, were planted in each of 24 sand tanks. Trees were irrigated daily with a standard nutrient solution with an EC of 3.5 dS/m. Trees irrigated with the nutrient solution alone served as the experimental controls.
Table 1. Composition of salts in the four treatments.
Salts are measured in (mol/m3), the molar concentration
of the salt in a liter volume.
Irrigation treatments consisted of four water qualities designed to simulate the saline-sodic drainage waters typical of the SJV (Table 1). Each was replicated six times. Treatment waters were pumped from reservoirs to the tanks, and returned through a drainage system. At each irrigation, 9x the maximal daily requirement to evapotranspiration (ET) was applied, thus the composition of the sand water was similar to the treatment water. Treatments commenced in April 1999.
Plant measurements included leaf chlorophyll using a SPAD meter and leaf porometer measurements. Trees were harvested in October 1999, and the trunk and canopy measurements were taken. Leaf area and the ratio of injured to noninjured leaf tissue was determined. Leaf and woody tissue was also analyzed for specific salts (P, CA, Mg, Na, K) and boron.