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Canopy Measurements as Predictors of Weed-Crop Competition

Published online by Cambridge University Press:  12 June 2017

J. I. Vitta
Affiliation:
Dep. de Cereales y Leguminosas, S.I.A. de la Com. de Madrid, Aptdo. 127, 28800 Alcala de Henares (Spain)
C. Fernandez Quintanilla
Affiliation:
Centro de de Ciencias Medioambientales, Consejo Superior de Investigaciones Científicas (CSIC), Serrano 115 dpdo, 28006 Madrid, Spain

Abstract

The development of weed management systems requires accurate prediction of weed-crop competition. In this paper, simple regression models of crop yield losses based on weed density and weed leaf area are compared. In weed leaf area models, variations in the relative damage coefficient (q) were also analyzed. Finally, three simple methods to assess weed cover were compared: visual, photographic, and optic device assessment. Leaf area models were at least as accurate as weed density models. However, the generality of the leaf area models was restricted by changes in q, according to the date of leaf area evaluation and the year. Although all methods to assess weed cover correlated adequately with weed leaf area, visual estimates were the best to predict crop yield losses perhaps because very low levels of weed leaf area could be distinguished visually better than by other methods.

Type
Weed Biology and Ecology
Copyright
Copyright © 1996 by the Weed Science Society of America 

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