Crop Weediness, Soil Seed Bank and Yield of Winter Wheat Spelt under Organic Agriculture

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. Purpose of investigation was to evaluate winter wheat spelt (Triticum spelta L.) 'Franckenkorn' agrophytocenoses at three growth stages of two sowing times under conditions of organic agriculture. In the experiment crop weediness and soil weed seed bank were established at three growth stages of winter wheat spelt and weed mass influence on the spelt grain yield. For experiment establishment standard research methods were used. In the spelt crop of later sowing, weeds spread and accumulate air-dry mass more intensively than in the crop of earlier sowing. During crop vegetation air-dry weed biomass regularly increased from 0.22 to 3.55 g m(-2) and from 0.52 to 10.63 g m(-2). Soil weed seed bank did not change essentially comparing crop soil before and after over-wintering of the winter wheat spelt. At hard stage of wheat maturity, weed seed bank significantly increased in both crops of different sowing time. Cereal earlier or later sowing time did not significantly influence winter wheat spelt grain yield. Because of particularly low crop weediness, homologous wheat grain yield dependences on crop weed mass were not established.