Characterizing Soil Based on Chemical and Physical Properties

A demonstration project for the State Water Resources Control Board consisting of two bioengineered systems, biotrenches and bioswales, will be used to treat agricultural runoff for excess nutrient loading of nitrates, phosphates, and pesticides. This field experiment is being conducted in Santa Paula, California between agricultural areas and the Santa Clara River where all the soil samples were taken. To characterize the physical properties it is important to measure bulk density, specific gravity, moisture content, and texture analysis (particle size) using American Society for Testing and Materials standards. After concluding physical characteristics, chemical properties such as cation exchange capacity, soil organic matter, and dissolved organic matter are measured using the same standards. These experiments will enhance our knowledge of ground water and surface runoff being transported from the fields prior to entering the river. Predicted outcomes for both treatment systems are expected to be around a 60% reduction of pesticides and a 30% reduction of nutrients which will significantly reduce total daily loads.