Volume 9
Issue 3
Agronomy
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume9/issue3/abs-08.html
USE OF MULTIVARIATE ANALYSIS OF VARIANCE AND DISCRIMINANT ANALYSIS TO EVALUATE CHANGES IN WEED COMMUNITY IN WINTER WHEAT DEPENDING ON HERBICIDES DOSE
Agnieszka Kubik-Komar1, Maria Jędruszczak2, Mirosława Wesołowska-Janczarek1
1 Department of Applied Mathematics,
University of Agriculture in Lublin, Poland
2 Department of Soil Tillage and Plant Cultivation,
University of Agriculture in Lublin, Poland
ABSTRACT
The paper is an attempt at evaluating changes in the weed community in winter wheat grown in short-term monoculture as a result of the application of 100, 75, 50, 25 and 0% of the recommended dose of Puma 069 EW (fenoxaprop-P-ethyl) and Aminopielik 450 SL (2,4D + dicamba). A two-factor field experiment carried out over 1997-2000, which involved tillage method and herbicides doses, provided data analyzed in the present paper, limited to the reaction of weeds to the herbicide doses only. Relative abundance of weeds, representing a given weed community was determined, based on species frequency and relative density of individuals which occur in test area (Ra index). The experimental data were verified with multivariate analysis of variance and discriminant analysis. The data were analyzed separately both in successive research experiment years and field weed infestation evaluation dates, namely I – prior to herbicide application, II – about 15 days after application and III – prior to winter wheat harvest. Significant differences between the average Ra values resulting from herbicides doses were found at all the dates analyzed, except for the spring date (II) in 1999. Besides, with the Mahalanobis distance square (M2) revealed that 75% of the recommended dose caused the greatest changes in the average relative weed abundance throughout the research period. However, with such inconsiderable dose differences, the graphic representation of the discriminant analysis results was hardly clear. Therefore three doses of herbicides (zero, low and high) were applied and at high M2 values species strongly related to the dose at respective dates were demonstrated. Dose-specific species pattern was changing depending on the observation date; most frequently such changes were found in APESV, LAMAM, LAMPU, CHEAL, VIOAR, VERAR. There also species connected with one dose only (e.g. CAPBP and MATIN – zero, GALAP, MYOAR – low and STEME – high). In successive experiment years the dynamics of changes in the average relative abundance (Ra) increased. The multivariate statistical methods used are applicable to evaluate changes in the weed community affected by the herbicide dose. The more diverse the levels of the factor studied, the more clear the representation of changes.
Key words: herbicides, multivariate analysis of variance and discriminant analysis, weed control.
Agnieszka Kubik-Komar
Department of Applied Mathematics,
University of Agriculture in Lublin, Poland
email: agnieszka.kubik@ar.lublin.pl
Maria Jędruszczak
Department of Soil Tillage and Plant Cultivation,
University of Agriculture in Lublin, Poland
email: maria.jedruszczak@ar.lublin.pl
Mirosława Wesołowska-Janczarek
Department of Applied Mathematics,
University of Agriculture in Lublin, Poland
email: miroslawa.wesolowska@ar.lublin.pl
Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.