Nutrition of Mycorrhizal Soybean Evaluated by the Diagnosis and Recommendation Integrated System (DRIS)
- Gabor J. Bethlenfalvay ,
- Raymond L. Franson and
- Milford S. Brown
Colonization of roots by vesicular-arbuscular mycorrhizal (VAM) fungi affects host-plant growth and nutrition, but standard methods to evaluate VAM effects are lacking. The Diagnosis and Recommendation Integrated Syslem (DRIS) may serve this purpose, and an analysis of mycorrhiza-mediated nutrient-uptake effects on soybean [Glycine max L.) M'err. CY. Hobbit) plants by DRIS is presented. Plants were grown either colonized by one of three geographical isolates of the VAM fungus Glomus mosseae (Nicol & Gerd) Gerd and Trappe or as nonVAM controls in a nutrient-deficient soil. Plant development and nutritional status differed among the treatments. Analysis by DWS confirmed that N, P, and K were limiting, and established different rankings in the degree of deficiency for each nutrient. Nitrogen was least limiting in all four treatments and K or P were most limiting in each of two treatments. The analysis permitted a ranking of the G. mosseae isolates as to their effects on the uptake of each nutrienl. Evaluation of VAM-mediated nutrientuptake effects by DRIS and by nutrient-dilution and concentration analyses could become useful in the selection of specific VAM fungal isolates for their specific crop responses.
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