The effect and dynamics of weed competition on maize in Germany and Benin

Publication Type

Contribution to conference

Authors

Martina Keller and Geoffroy Gantoli and Alexandra Kipp and Christoph Gutjahr and Roland Gerhards

Year of publication

2012

Published in

Proceedings of the 25th German Conference on Weed Biology and Weed Control

Editor

Henning Nordmeyer and Lena Ulber

Pubisher

Julius-Kühn-Institut , Berlin, Germany

Band/Volume

434/

Series/labeling

Julius-Kühn-Archiv

ISBN / ISSN / eISSN

978-3-930037-84-1

DOI

10.5073/jka.2012.434.036

Page (from - to)

289-300

Conference name

25. Deutsche Arbeitsbesprechung über Fragen der Unkrautbiologie und -bekämpfung (25th German Conference on Weed Biology and Weed Control)

Conference location

Braunschweig

Conference date

13.-15. März 2012

Four field experiments were carried out in maize at one location in Southern Germany (2009 and 2010) and at two locations in West Atacora, Benin (2010), to determine and compare the effect and dynamics of weed competition under two different environments. Further aims were to determine the critical period for weed control in Benin to provide recommendations to farmers on weed control strategies. Weeds were removed at different crop growth stages of the crop: Emergence, 4-, 8-, 10-leaf stage and flowering and maize plots were kept weed-free until harvest. In Benin, weeds were additionally removed until the aforementioned growth stages and then allowed to reemerge until harvest. Crop growth parameters and weed biomass were monitored over the whole growing season. Dry grain yield was recorded at harvest. Logistic and Gompertz equations were used to determine the critical period for weed control. The four main weeds in Germany were the dicotyledonous species Chenopodium album, Galium aparine, Stellaria media and Capsella bursa-pastoris. In Benin, the two grasses Setaria pumila and Bulbostylis hispidula and the two dicotyledonous weeds Stachytarpheta indica and Mitracarpus villosus prevailed. For all sites, the main weeds were primarily annual species. In Germany, grain yield levels without weed competition ranged from 8.5 to 10.3 t/ha; in Benin the average yield was considerably lower (3.4 t/ha). As expected, yield loss increased significantly with duration of weed competition and yield losses were highest in the control amounting to 49-86 % (Germany) and 38-58 % (Benin). For Benin, the results confirmed that weeds have to be controlled from about the 4-leaf stage until almost flowering to reduce yield loss below 20 %. As weed control is mainly done by hand, this is difficult to achieve due to the shortage of family labor and the high costs of hired labor.