Achieving Nodulation in Guar: Investigating the Impact of Management Factors.

Guar is a summer legume that produces a seed containing galactomannan gum that is used in many industrial and food applications as a lubricant, thickener, binder, and hardener. The primary U.S. production area for guar is the Southern Great Plains. Some have reported that guar does not nodulate effectively in this environment, limiting its contribution to soil health and nitrogen fertility, though little scientific work has been done verify or characterize this. In this greenhouse study, we investigated the impacts and interactions of rhizobium inoculant [Micronoc (SonoAg, Hale Center, TX), USDA 3385 bradyrhizobium, and no inoculant], soil type (sandy loam and clay loam), and guar variety (Lewis and Kinman) on nodulation in guar in Vernon, TX. The study consists of two iterations. At the end of first iteration of the study, data was recorded for the nodule counts, nodule weight, number of fruiting/flowering nodes, and total plant biomass. The size and number of nodulations varied depending upon the soil type in our preliminary observations. However, the final results will give us a better understanding on that regard. The results of this study will broaden our knowledge of the conditions under which successful nodulation of guar can be achieved in the Southern Plains region.