Evaluation of Soybean Zinc and Manganese Requirements by the M-DRIS and Sufficiency Range Methods
- W. B. Hallmark ,
- R. B. Beverly,
- M. B. Parker,
- J. F. Adams,
- F. C. Boswell,
- K. Ohki,
- L. M. Shuman and
- D. O. Wilson
- I beria Res. Stn., Louisiana State Univ. Agric. Ctr., P.O. Box 466, Jeanerette, LA 70544
H orticulture Dep., Georgia Exp. Stn., Griffin, GA 30223
D ep. of Agronomy, Coastal Plain Stn., Tifton, GA 31793
D ep. of Agronomy and Soils, Auburn Univ., Auburn, AL 36849
D ep. of Agronomy, Georgia Exp. Stn., Griffin, GA 30223
The modified-diagnosis and recommendation integrated system (M-DRIS) and sufficiency range method (SUM) have not been compared for accuracy of Zn and Mn diagnoses for soybean [Glycine max (L.) Merr.]. Consequently, M-DRIS and SRM were evaluated for diagnosing Zn deficiencies for two site-years in Alabama, and Mn deficiencies and sufficiencies for three site-years in Georgia. The SRM was more accurate than M-DRIS in detecting when Zn was deficient (P < 0.05) and when Mn was not deficient (P < 0.01). However, M-DRIS and SRM did not differ (P > 0.10) where Mn was deficient. Partial regression analysis indicated that M-DRIS also incorrectly diagnosed Ca as deficient in the Alabama studies. False M-DRIS diagnoses of Mn and Ca deficiencies were attributed to their inflated concentration and ratio means in the M-DRIS data base, which may also have contributed to false diagnoses of K, Mg, Cu, and Fe deficiencies in the Georgia study. Results demonstrate the danger of using inflated nutrient means in M-DRIS diagnoses. Further work is needed to improve the diagnostic accuracy of MDRIS.
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