GLP soil characterization--the laboratory.

Good laboratory practices (GLP) for field studies have been implemented to provide accurate and complete data in all phases of field trials, including the characterization of the soil where the test system is grown. The soil characterization analysis generally offers two packages or series of analyses from which the sponsor may select. The Series I soil characterization is more comprehensive than the Series II. The Series II characterization includes pH, percent organic matter, cation exchange capacity (CEC), bulk density, percent sand-silt-clay, U.S. Department of Agriculture textural class, and 1/3-bar water-holding capacity. In addition to these analyses, the Series I characterization includes: 15-bar water-holding capacity, and percent total nitrogen, phosphorus, and soluble salts.