Julius-Kühn-Archiv (Mar 2012)

Composition of weed populations in maize as a function of plant or crop management: Results of a nation-wide survey in Germany conducted from 2002 to 2004

  • de Mol, Friederike,
  • von Redwitz, Christoph,
  • Schulte, Martin,
  • Gerowitt, Bärbel

DOI
https://doi.org/10.5073/jka.2012.434.085
Journal volume & issue
no. 434
pp. 655 – 662

Abstract

Read online

Data sets, comprising information on weed densities of 1103 maize fields in Germany as well as their crop management practices and site-specific characteristics, were analysed. The objectives were to describe the joint occurrence of weeds and to asses the influence of crop management on weed species composition.Per field, weed densities were assessed in ten, 0.1 m2 quadrats in young maize (2-6 leaves) before herbicide application. Fields were distributed all over Germany but the emphasis was on regions with high proportions of maize. Weed species composition was described with correspondence analysis and partial canonical correspondence analysis, using geographic location, climate, soil, and year as conditions. Tillage (mouldboard or chisel), crop rotation (proportion of maize and oilseed rape; maize as previous and/or pre-previous crop), maize density and whether or not manure was applied were added as independent crop management parameters. The net effects of these parameters were tested with a permutation test and were proved to be significant (p < 0.05).The relationship between weed density and herbicide use was analysed on a 200 field subset, involving 17 weed species. The potential herbicide use intensity was deduced from the efficacy data of advice papers. There was a significant relationship between the respective distance-matrices (rM = 0.21; p = 0.04). To visualize this relationship, separate correspondence analyses were conducted on weed incidence and theoretical herbicide effects, and a Procrustes analysis was performed. A Procrustes test indicated a correlation of 0.42 (p = 0.11) between weed assembly and herbicide use, which was characterized by the theoretical herbicide-weedefficacy. Consequently, in particular with crop rotations farmers seems to have a powerful tool to influence weed species composition.

Keywords