About effect of weeds on spectral reflectance properties of winter wheat canopy

Among the poorly studied factors affecting the spectral reflectivity of crops and, consequently, the success of detection of their condition based on remote sensing data is crop weedness. On the basis of field survey data, the effect of weed infestation on winter wheat spectral reflectivity at different stages of vegetation was analyzed using the example of individual fields in the Tula region with chernozems, grey forest, and alluvial arable soils. Under field conditions, crop weedness, spectral reflectance of crops, weeds, winter wheat leaves and soil was determined using FieldSpec® HandHeld 2™ field spectro-radiometer (ASD, Inc., USA) was assessed several times during the growing season, and the crop surface was photographed. The decoding of the photos showed that the projective weed coverage on the crop surface is low enough at the beginning and middle of the wheat growing season, but increases significantly since the beginning of leaves yellowing. At the same time, the projective coverage of weeds in the field with chernozems was minimal at the beginning and middle of the growing season, and maximal - by the end of the growing season...