A Crop Stress Index to Predict Climatic Effects on Row-Crop Agriculture in the U.S. North Central Region - The Ecology of Agricultural Landscapes - page 91

Figure 4.8 . Distribution of the mean Crop Stress index (CSI) by county in the NCR during (A) May, (B) June, (C) July, and (D) the mean CSI
sum for May—July from 1971-2001. See Fig. 4.6 for data sources.