Fig. 1. Median North Carolina Mehlich-3 soil test P index values for all crops by county for the year 2003. Data are from soils submitted to the North Carolina Department of Agriculture and Consumer Services, Soil Testing Division. Data compiled by R. Austin and D. Osmond, North Carolina State University, Department of Soil Science. A soil test index value of >50 indicates a site on which crops are not expected to show a response to further P additions.