|Mitchell, J. - UNIVERSITY OF CALIFORNIA|
Submitted to: Proceedings California Plant and Soil Conference Farming in Crisis
Publication Type: Abstract Only
Publication Acceptance Date: January 20, 2000
Publication Date: N/A
Technical Abstract: Managers need decision tools for sustainable management. Indices of soil quality may fill this need. We tested 2 methods for choosing a minimum data set (MDS) and 2 methods of index formation. Ten years of chemical, biological, and physical data from vegetable rotations of the Sustainable Agriculture Farming Systems (SAFS) project, near Davis, CA, were used. The MDS components were chosen using principal components analysis (PCA) or expert opinion. Indices were created using an additive index or a decision support system. The efficacy of each minimum data set was tested by multiple regression of MDS variables against management variables such as yield, % weed cover, and water use. For the MDS chosen by PCA for tomato, R**2 values were 0.64 against yield, 0.97 against weeds, and 0.99 against water use. The corn MDS regressed against yield, weeds, and water use had R**2 values of 0.81, 0.90, and 0.90, respectively. Results are reported for organic, low-input and conventional treatments.