Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/26/2004
Publication Date: 2/10/2005
Citation: Papiernik, S.K., Grieve, C.M., Lesch, S.M., Yates, S.R. 2005. Effects of salinity, imazethapyr, and chlorimuron application on soybean growth and yield. Communications in Soil Science and Plant Analysis. 36:951-967. Interpretive Summary: Soybean is an important crop worldwide. Soybean cultivars differ in their sensitivity to soil salinity and herbicide damage. Little information exists on the combined effects of multiple stresses on soybean growth and yield. In these experiments, we examined the impact of salinization and herbicide application on the growth and yield of two soybean cultivars. For both soybean cultivars, growth parameters indicated that plants irrigated with fresh water were consistently larger and faster-growing than plants irrigated with saline water. Cultivar differences were observed in yield, where for one cultivar, plants irrigated with fresh water had significantly larger yield components than plants irrigated with saline water, while the opposite response was observed for the second cultivar. Herbicide treatment significantly impacted several growth parameters, but there was no observable reduction in yield as a result of herbicide application in either salinity treatment. A large proportion of agricultural land is affected by sulfate salinity, and the results of these experiments may help determine soybean response and herbicide injury in these systems, allowing for better herbicide and cultivar selection and improved yields.
Technical Abstract: Soybean (Glycine max L. Merrill) is an important crop worldwide. Soybean cultivars differ in their sensitivity to soil salinity and herbicide damage. In these experiments, we examined the impact of salinization and herbicide (imazethapyr and chlorimuron ethyl) application on the growth and yield of two soybean cultivars, 'Essex' and 'Manokin'. Experiments were conducted in small pots in the greenhouse, in outdoor sand cultures, and in drip-irrigated field plots. Plants were irrigated with fresh water (electrical conductivity, EC = 2 dS/m) or saline water (EC = 7 dS/m) with a composition typical of areas affected by sulfate-dominated salinity. Morphological changes resulted from herbicide application, including leaf elongation and formation of large shoots at the cotyledonary node. For both soybean cultivars, salinity and herbicide treatment had a significant impact on main stem height, number of nodes on the main stem, total leaf area, and stem diameter. Salinity reduced growth of Essex to a greater extent than Manokin. Herbicide-treated plants tended to be smaller than non-treated plants, but responses from the two herbicides were not significantly different. Salinity had a significant effect on seed weight: Essex plants irrigated with fresh water had significantly larger yield components than plants irrigated with saline water, while Manokin yield parameters were significantly larger for plants irrigated with saline water. No yield differences were observed between herbicide treatments.