Submitted to: Pacific Division American Association for the Advancement of Science
Publication Type: Proceedings
Publication Acceptance Date: 6/21/1999
Publication Date: N/A
Technical Abstract: California's Central San Joaquin Valley (SJV) is one of the world's most productive agricultural regions. Changes in cropping patterns in this area during the last 30 years have resulted in intensified production and concerns about the quality of the soil resource base. In 1995, the West Side On-Farm Demonstration Project was initiated with 14 large-scale SJV farmers to evaluate a variety of alternative soil management practices including compost and manure applications and cover cropping. A data set of soil quality indicator properties was identified and compiled at each on-farm demonstration in the spring and fall of each year of the project. At demonstration sites that maintained somewhat consistent and deliberate management programs between the conventional and alternative fields during the course of the project, differences in a number of indicator properties resulted. Indicators that tended to change the most frequently included total soil carbon, microbial biomass carbon and nitrogen, exchangeable potassium, and organic matter. These data provide the basis for the development and testing of a soil quality index and considerable extension education throughout the region.