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r ." . - 583 - 4 2 . 0.37 t:::1 3 2 2 . I- 0.47 4 3(/) Z . W w 0.69 41- z ~ 0 Z Q.. . ~ ='E I 6 0.85 50 0 . U 0 . 0.89 u 0.18 6 I I 0 2 4 -I 0 COMPONENT I Fig. 8 - Counties mapped on principal components, with annual precipitation amounts and their dendritic clustering A. Intensive-Farming Complex Ample precipitation ~luch harvested cropland ~luch value in equipment Dense population Industry-added value Cropland grazed Cropland in cover High value/farm acre Oats produced B. Ranching Complex C. 'Irrigation-Fallow Complex ~luch idle cropland ~luch hay produced Much head of cattle raised Much corn produced Many sheep raised Much failed cropland Little of land farmed Much wheat produced Much irrigated land ~luch fallow cropland Much wheat produced Much pasture and range Much rye produced Large farms ~luch barley grown Low value/farm High ranking in a list implies only that the descriptor is present to a greater extent in that group than in others; it does not infer importance to that descriptor in the function- ing of the complex. Several conclusions follow from even this preliminary exploration of the methods. First, the principal component distinguishing county from county is strongly correlated with precipitation, and there is a secondary component perhaps nonlinearly related to precipita- tion. second, the complex of descriptors characteristic of intensive farming is strongly correlated with precipitation. Third, there are abundant suggestions of more varied and complex dependencies, direct and indirect, on precipitation. Fourth, more sophisticated selection of data, focused on selected issues, promises great improvement in the sharpness with which the issues can be resolved. Application of various classification procedures to refinement of the method of homoclimes appears very feasible. Application to data sets drawn from aspects of the environment other than farming is contemplated. 5. Conclusions a. An integrative or holistic approach to describing how precipitation management may affect environments forms a valuable and necessary complement to the componential approach. The understanding it may yield of how precipitation is related to an environmental system as a ~hole is beyond the reach of present analytic approaches that deal with effects of precipitation management on one or another component. b. To study effects spanning 10 years or less, it is best to examine changes that have occurred in the study area itself during past natural precipitation fluctuations of the same sort as those expected to result from precipitation management.