Spectral discrimination between soybean and Johnson grass as tool to selective herbicide application

ACCIARESI HORACIO; YANNICCARI, MARCOS; WEBER, C.

Baltimore

Congreso; 53th Annual Meeting of the Weed Science Society of America (WSSA); 2013

WSSA

In recent decades the Argentinean agriculture development was closely linked to the soybean culture expansion, as well as with direct sowing as cultural practice. Consolidation of this sowing system, the use of glyphosate herbicide virtually exclusive and scarce or null rotation with glyphosate-resistant soybean (RR), have resulted in diversity and abundance of many weeds species decreases. Those facts have meant a significant selection pressure over weeds that are not controlled by glyphosate. This pressure helped to the evolution of weed resistant biotypes, as example the Johnson grass (Sorghum halepense (L.)) (S. h). The S.h. is one of main important weeds in the world, that in Argentina. In this study, experiments were conducted to examine the use of spectral reflectance curves to discriminate between RR/S.h plants species. S.h and RR plants were grown in pots, and spectral reflectance data were obtained in various phenological stages of weed and crop.. The ability to discriminate between crop and weeds was not affected by the different phenological stages Spectral signatures curves provided an accurate classification among weeds and crop. This suggests that these data are potentially be used to discriminate crop and weed in field scenarios. This information can be helpful to apply site-specific herbicide application and consequently to vary active ingredient to help delay the resistance onset.