Preliminary DRIS Norms for Alfalfa in the Southeastern United States and a Comparison with Midwestern Norms1

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Abstract
Foliar tissue norms were developed for ‘Apollo’ alfalfa (Medicago sativa L.) grown on two highly weathered soils in the Georgia Piedmont for use in the diagnosis and recommendation integrated systems (DRIS). These norms were generated from a data bank comprised of tissue nutrient composition and plant yield and consisting of 3915 field observations. A yield of 3.5 Mg ha−1 per cut was used to divide high yielding from low yielding members. Norms were generated by averaging values from the high yielding segment for all possible ratios of N, P, K, Ca, Mg, Zn, Cu, B, and dry matter (DM) and compared to those previously calculated from midwestern data. Values from Georgia were generally similar to those from the Midwest, except for Mg, which was lower, and B, which was higher. Differences in Mg norms were attributed to soil conditions. Norms generated in Georgia correctly diagnosed nutrient requirements of plants grown in Georgia, but differences between the two sets of norms indicate some regionality in DRIS norms for alfalfa. The DM index was demonstrated to adequately separate nutrients present in sufficient and insufficient quantities for recommendation purposes.