Luba NENOVA, Iliana IVANOVA, Svetlana STOYANOVA
Abstract. During the period 2008–2010 at the Experimental field of IASS “Obraztsov chiflik”–Rousse a field experiment was conducted, including cultivation and rotation of crops: beans Obraztsov chiflik” variety, wheat Yantur variety, soybeans Zarya variety, and wintering oats line RS–2 in four–field crop rotation under conditions of organic farming. The experiment started after the Block method in two variants–controls (without fertilization) and foliar fertilization by the humate fertilizer Humustim in four replications, the size of harvesting plot being 52.5 m2. In crop growing in crop rotation technological schemes were applied according to the requirements of the organic farming without using chemicals, following the Regulation N 22 from 04.07.2001 of MAF for organic plant production. The field experience was located in an area, where two–year period of conversion was observed. During the period of investigation in crops of crop rotation, the density of perennial weeds had remained relatively constant. In variants with fertilization by Humustim the total number of weeds was lower than those without fertilization. It was founded from the monitoring that the lowest density of weed infestation was observed in wintering oats, grown after soybeans–100 pcs./m2 and in wheat, grown after field beans–122 pcs./m2.
Keywords: field crops, weed infestation, organic farming