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Prognose des Wachstums und der Konkurrenz einjähriger Unkräuter in Weizen
Author(s) -
WILSON B. J.,
WRIGHT KATHRYN J.
Publication year - 1990
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1990.tb01704.x
Subject(s) - galium , weed , stellaria media , biology , agronomy , crop , avena fatua , competition (biology) , weed control , interspecific competition , papaver , crop yield , cirsium arvense , botany , ecology
Summary: The growth and competitiveness of 12 annual weed species were studied in crops of winter wheat, in which weeds were sown to give a wide range of plant densities. Weed growth patterns were identified; early species which senesced in mid‐summer were less competitive than those with a growth pattern similar to that of the crop. Most species had little effect on crop yield in 1987, and this was attributed to a high crop den sity. Crop yield‐weed density relationships for all species in 1988 and for Galium aparine in 1987 were well described by a rectangular hyperbola. Species were listed in the following competitive order based on the percentage yield loss per weed m −2 : Avena fatua > Matricaria perforata > Galium aparine > Myosotis arvenis > Poa trivialis > Alopecurus myosuroides > Stellaria media > Papaver rhoeas > Lamiumpur‐pureum > Veronica persica > Veronica hederi‐folia > Viola arvensis . Prediction of yield loss is discussed. The assumptions inherent in using Crop Equivalents (based on relative weights of weed and crop plants), are challenged; with intense competition, weed biomass at harvest failed to replace lost crop biomass, and harvest index was reduced. It is concluded that a competi tive index, derived from yield density relation ships, and expressed as the percentage yield loss per weed m −2 , is more likely to reflect the com petitive ability of a species than an index obtained from plant weights in the growing crop.