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The accuracy of soil and plant analytical results are occasionally called into question by laboratory clientele. Although laboratories generally conduct internal quality assurance procedures, there are few external performance testing programs for the industry. In the spring of 1994, a proficiency testing program was initiated for soil and plant samples for agricultural laboratories in the Western United States to provide an external quality control for the laboratory industry. The program involves the quarterly exchange of soil and plant samples on which soil salinity, soil fertility, and plant nutrition analyses are conducted. For the 1994 program, 103 laboratories from 23 states and Canadian provinces participated. Overall, soil salinity and pH analyses were highly reproducible across soils and laboratories through the year. Variability in soil nitrate results were lower than noted in past interlaboratory exchanges independent of soil sample. Results for extractable soil bicarbonate phosphorus...

DRiWATER*, a poly cellulose gel containing 97.98% water, is a moisturizing substrate made from cellulose gum, alum and aerated water. The substrate which is decomposed by micro‐organisms slowly releasing water, is intended for use on house plants, other container grown plants and newly planted trees and shrubs as a substitute for frequent or costly watering. The manufacturer's label claims that the substrate will water plants for 30 days, will save time and water, and eliminate over watering. A test to determine the efficacy of the poly cellulose and to verify label claims was conducted. Four replicates of two rates of water, three rates of the substrate and an unirrigated check were applied to azaleas, Rhododendron indicum, in one gallon pots. Poly cellulose treated plants were maintained through a four week period. The gel disappeared over a 3 to 4 week period. Irrigated plants grew well. Efficacy claims for DRiWATER* were substantiated.