Weed seedling over-wintering and vegetation dynamics in organically grown winter wheat spelt crop under climate changing conditions

Abstract

The experiment was carried out at the Perloja Experimental station of the Lithuanian Research Centre for Agriculture and Forestry during 2010–2011. The experimental soil was Hapli-Albic Luvisol. Winter wheat spelt (Triticum spelta L.) 'Franckenkorn' agrophytocenoses weed seedling over-wintering and dynamics under changing climate conditions of two crop sowing times in organic agriculture were investigated. Winter wheat spelt crop weed seedling over-wintering and continuous density dynamics were established arranging three fixed plots of 0.25 m2 (total 24 continuous plots) in each experimental plot. A coloured marker for each evaluation using different colour near new germinated weed seedlings was stacked. Unsurvived, i.e. dead weed seedlings were calculated collecting stacked markers. Marker colours near dead seedling indicated date of seedling emergence. Weed seedlings were counted each month according to the experimental design in the crop in autumn (BBCH 13), during wintering (BBCH 13), in spring (BBCH 25-37) and summer (BBCH 49-87) vegetation of winter wheat spelt. Weed seedling germination, death and total dynamics during vegetation of winter wheat spelt agrophytocenoses of different sowing time was in confirmity with general weed germination dynamics. During over-wintering (January – March) the highest weed seedling death was established. In organic winter wheat spelt crop of earlier sowing during winter 76.7% of all during autumn germinated weed seedlings unsurvived. In the crop of later sowing only 12.9% of all during autumn germinated weed seedlings were dead in the crop. Uniform number of weed seedling total number, germination and death in organically grown winter wheat spelt agrophytocenoses during June – August were influenced by the meteorological conditions