Submitted to: Pesticide Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2014
Publication Date: 3/13/2015
Citation: Huang, Y., Reddy, K.N., Thomson, S.J., Yao, H. 2015. Assessment of soybean injury from glyphosate using airborne multispectral remote sensing. Pesticide Management Science. 71:545-552. Interpretive Summary: Traditional method of detecting crop injury from herbicide using biological responses, such as plant height and leaf chlorophyll content, is laborious and time-consuming. Remote sensing is expected to create a more convenient and rapid detection method. The scientists at USDA-ARS Crop production Systems Research Unit, Stoneville, MS, and Geosystems Research Institute, Mississippi State University, have collaboratively conducted a study to determine the effects of glyphosate on biological responses of non-glyphosate-resistant soybean and their relationship with the vegetation indices derived from aerial multispectral imagery. The results indicated that the vegetation indices were closely related the plant height and the crop yield but poorly related to chlorophyll regardless of one, two or three weeks after glyphosate treatment. This study suggests that airborne multispectral remote sensing could be used to determine soybean injury from glyphosate.
Technical Abstract: BACKGROUND: Glyphosate drift onto off-target sensitive crops can reduce growth and yield, and is of great concern to growers and pesticide applicators. Detection of herbicide injury using biological responses is tedious, so more convenient and rapid detection methods are needed. The objective of this research was to determine the effects of glyphosate on biological responses of non-glyphosate-resistant (non-GR) soybean and to correlate vegetation indices (VIs) derived from aerial multispectral imagery. RESULTS: Plant height, shoot dry weight, and chlorophyll content decreased gradually with increasing rate regardless of weeks after application (WAA). Accordingly, soybean yield decreased by 25% from 0.0X to 1.0X. Similar to biological responses, the VIs derived from aerial imagery, NDVI (normalized difference vegetation index), SAVI (soil adjusted vegetation index), RVI (ratio vegetation index), and GNDVI (green NDVI), also decreased gradually with increasing glyphosate rate regardless of WAA. CONCLUSION: The VIs were highly correlated with plant height and yield but poorly correlated with chlorophyll regardless of WAA. This indicated that indices could be used to determine soybean injury from glyphosate as indicated by the difference of plant height.