Diagnosing Nutrient Deficiencies in Soybean, Using M‐DRIS and Critical Nutrient Level Procedures

Abstract

Plant nutrient deficiencies may be diagnosed with DRIS (diagnosis and recommendation integrated system) or critical nutrient level (CNL) procedures. While extensive efforts have been made to improve diagnoses by DRIS and M‐DRIS, little has been done to refine CNL diagnoses for soybean [Glycine max (L.) Merr.]. In this study, we compare diagnoses made by M‐DRIS with those from CNL and modify these procedures to improve their diagnostic accuracy. Two databases of R2 (full bloom) soybean leaf nutrient concentrations from 828 field observations of known K, Mn, Zn, or P deficiencies or sufficiencies were used for comparing the procedures. We optimized critical nutrient levels (modified CNL) using the same cases from a database that was used earlier to improveM‐DRIS. Using this optimization database, the M‐DRIS and modified‐CNL procedures had ≤ 13 misdiagnoses each of K nutrient status compared to 81 by unmodified CNL. M‐DRIS was more accurate than the two CNL procedures in diagnosing P deficiencies from cases in the optimized and independent data sets. Unmodified CNL produced 18 misdiagnoses for Zn status from cases in the independent data set, versus >27 for M‐DRIS or modified CNL. Generally, M‐DRIS was the same or more accurate than CNL methods in diagnosing nutrient status. We recommend CNL concentrations for R2 stage soybean of 3.1 g P kg−1, 15.1 g K kg−1, 17 mg Mn kg−1, and 21 mg Zn kg−1. For M‐DRIS, we recommend critical index values of zero for K and Mn, 18 for P, and −19 for Zn.

Starch and nitrogen status in soybean during shading and nutrient deficiency

“…The range for P in that same study is 0.31 to 0.50% for sufficiency, and less than 0.31% to be deficient in P. In Arkansas, soil and plant diagnostic tests are done in a site-specific manner, where plants from a good area of the field are compared to plants from a poor area in that same field. We find tissue levels of P and K in soybean are often at the lower ends of the ranges listed in Bell et al (1995). Frequently plants that have deficient levels of P and K do not result in yield reduction.…”

“…A recent survey of the combined data banks for nutrient levels of soybean grown in Alabama, Arkansas, Iowa, Georgia, and Louisiana report the recommended critical nutrient concentrations of K to be between 1.25 and 2.5% for sufficiency, and below 1.51% for deficiency (Bell et al, 1995). The range for P in that same study is 0.31 to 0.50% for sufficiency, and less than 0.31% to be deficient in P. In Arkansas, soil and plant diagnostic tests are done in a site-specific manner, where plants from a good area of the field are compared to plants from a poor area in that same field.…”

Soybean Cultivar Differences in Ureides and the Relationship to Drought Tolerant Nitrogen Fixation and Manganese Nutrition

“…Although these effects of Mn treatment were significant, the concentrations were three to four times greater than those seen in the greenhouse experiment. These concentrations are relatively high but are considered nontoxic for soybean growth (Bell et al, 1995)…”

Diagnostic Efficiency of the Blacklayer Stalk Nitrate and Grain Nitrogen Tests for Corn

“…The selection of the right P c will undoubtedly be some function of the rate of acceptable failure to several different groups, including farmers, environmental groups and organizations, and private entities such as the insurance industry. Beverly's ER (Table 5) is one example of a weighting scheme that has been used in the tissue‐diagnostics literature (Bell et al, 1995; Beverly, 1993). His approach strongly favors the farmer's yield‐loss concerns (Beverly and Hallmark, 1992, Beverly 1993).…”