Effects of Different Fertilizer Sources on Weed Growth in Organic Wheat

Fertilization and weed control are the most significant problems in organic farming. Since herbicides are prohibited in organic farming, generally cultural, mechanical and biological practices are implemented for weed control. In current research, effects of 7 different fertilizer sources [control, standard inorganic (ammonium sulphate + triple superphosphate) (NP), soil amending bio-organic (Bio), soil amending bio-organic SR (Bio SR), organic soil amending leonardite (Leo), organic manure (OM) and cattle manure (CM)] on weed control in two wheat varieties (Kirik,Dogu-88) were investigated among the years 2006-2009. Weed intensity, frequency and dry weights were analyzed to assess the impacts of treatments on weed control. A total of 43 different weed species were observed in Dogu-88 plots and 45 different species were observed in Kirik plots during the entire experimental years. Average weed density for Dogu-88 and Kirik cultivars were found to be 36.6 weed m(-2) and 42.8 weed m(-2) respectively. However, the difference in weed density of cultivars was not found to be significant statistically. Significant differences were observed among cultivars with regard to weed densities and weed dry weights per square meter and dry weights were determined as 139.5 kg da(-1) for Kirik and 90.3 kg da(-1) for Dogu-88. While the lowest weed density was observed in OG (organic manure) treatment, the highest values were observed in CM (cattle manure) treatments with 40.0 weed m(-2) in Dogu- 88 and 49.5 weed m(-2) in Kirik. Dry matter yields of weed per unit area were lower in OM, Bio, NP, BioSR treatments than the other treatments. Along with current findings, Dogu- 88 cultivar with OG fertilizer can be recommended for organic wheat farming in Erzurum.