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Evaluation of arbuscular mycorrhiza populations for enhancing switchgrass yield and nutrient uptake
Abstract
To enhance the economic viability of switchgrass (Panicum virgatum L.) as a forage or biomass crop, rapid stand establishment and high yields are needed using low inputs, particularly nitrogen (N) and phosphorus (P) fertilizer. Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with mycotrophic species, and can increase water and nutrient uptake by their host, and colonization by AMF may be essential for plant establishment and survival with mycorrhizal dependent plant species. Arbuscular mycorrhizal fungal inoculum was collected from native and seeded switchgrass stands in Nebraska, Kansas, Iowa, Missouri, Virginia, and North Carolina. Four switchgrass cultivars were inoculated with AMF from each collection, and grown in sand cultures for 12 wk. Mycorrhiza inoculated plants produced 15-fold greater shoot and root yields, and recovered six-fold more N and 36-fold more P than non-mycorrhizal plants, indicating that switchgrass is highly mycorrhizal dependent. Plants inoculated with AMF from seeded switchgrass stands averaged 1.5-fold greater shoot and root yields than plants inoculated with AMF from native prairies. Switchgrass, big bluestem (Andropogon gerardii Vitman), sorghum (Sorghum bicolor L. Moench) and soybeans (Glycine max (L.) Merr.) were grown for 12 wk in sand cultures inoculated with three highly or three moderately effective AMF populations. Switchgrass and big bluestem responded similar to inoculation with the different AMF. However, sorghum and soybeans responses were different from switchgrass, suggesting that highly effective AMF associated with seeded switchgrass stands are not highly effective for these crops. Switchgrass seedlings were inoculated with highly effective, moderately effective, or indigenous AMF populations, and grown in cone-tainers for 12-wk prior to transplanting in a Sharpsburg silty clay loam (fine montmorillonitic mesic typic Argiudoll) and an Ortello loam (coarse loamy mixed mesic udic Haplustoll) near Mead, NE. Switchgrass yield or N- and P-uptake were not significantly different between the introduced and the indigenous AMF at either site. This may have resulted from the inability of the introduced AMF to compete with the indigenous AMF for colonization of new switchgrass roots.
Subject Area
Agronomy|Range management
Recommended Citation
Brejda, John Joseph, "Evaluation of arbuscular mycorrhiza populations for enhancing switchgrass yield and nutrient uptake" (1996). ETD collection for University of Nebraska-Lincoln. AAI9715956.
https://digitalcommons.unl.edu/dissertations/AAI9715956