Determination of economic threshold densities for the mayor weed species competing with bread wheat in Ethiopia
Material type:
TextPublication details: Addis Ababa (Ethiopia) CIMMYT : 1999ISBN: - 92-9146-058-3
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| Conference proceedings | CIMMYT Knowledge Center: John Woolston Library | CIMMYT Publications Collection | Look under series title (Browse shelf(Opens below)) | 1 | Available | W629146 |
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| Look under series title Indigenous agroforestry: | Look under series title A study of variety by management interaction in bread wheat varieties released in Ethiopia | Look under series title An agronomic and economic analysis of a long-term wheat-based crop rotation trial in Ethiopia | Look under series title Determination of economic threshold densities for the mayor weed species competing with bread wheat in Ethiopia | Look under series title Determination of economic optimum fertilizer levels using discrete and continuous analytical methods | Look under series title The response of bread wheat to N and P application under improved drainage on bichena vertisols in North-Western Ethiopia | Look under series title Pre- and post-emergence herbicides for irrigated wheat in Ethiopia |
Competition effects of four grass weed species (Avena abyssinica, Lolium temulentum, Snowdenia polystachya, and Phalaris paradoxa) and three broadleaf weed species (Guizotia scabra, Amaranthus retroflexus, and Galium spurium) on he grain yield, yield components and morphological characters of bread wheat (Triticum aestivum) were studied in Ethiopia. The weed species varied significantly in their effects on the number of fertile wheat spikes m-2, grains per spike, thousand grain weight, biomass and grain yield, harvest index and plant height. A. abyssinica and S. polystachya were the most competitive grass weeds, reducing wheat yield components and morphological characters to a greater extent than L. temulentum and P. paradoxa. Grass species by seedling density interaction effects were significant for most of the crop and weed characters measured, indicating a differential rate response for individual species. The reduction in wheat grain yield at the maximum grass weed density of 320 seedlings m-2 ranged from 48 to 86% across the four species studied. Among the three broadleaf weed species, G. scabra exerted the greatest effect on wheat grain yield. The wheat yield reduction at the maximum broadleaf weed seedling density of 160 seedlings m-2 was 47.8,29.6 and 18.6% for G. scabra, A. retroflexus, and G. spurium, respectively. Competitive yield losses were fitted to a rectangular hyperbola model to facilitate the prediction of wheat grain yield loss, and to derive economic thresholds for herbicidal intervention in relation to weed seedling density
English
0007|AGRIS 0101|R99-00CIMPU|AL-Wheat Program|AL-Economics Program
Jose Juan Caballero
CIMMYT Publications Collection