Effect of crop rotation and tillage types on weed seed bank

Crop rotation and tillage systems with affect the size, composition and distribution of weed seed banks have an important role in weed management. These experiments was conducted to evaluate the effect of crop rotation and tillage on soil seed bank of weeds in agriculture research center in Isfahan province.Soil sampleswere taken at three depths 0-10, 10-20 and 20-30Cm from the wheat research Farm was over 3 years (from October 2011) under three tillage systems (No- tillage, Minimum-tillage and moldboard plow) and six crop rotation (Barely-Corn-Wheat, rapeseed – sunflower-Wheat, Fallow-Sugarbeet-Wheat, Wheat – Fallow-Wheat, rapeseed – Fallow - Wheat, rapeseed – Corn-Wheat).The results showed that number of annual seeds and followed the number of annual species in the soil seed bank was highest density. Theannual seeds density at 10-0 depth was 4time than 30-20 depth, approximately. In between number annual, was greater the number of annual broadleaf than annual grasses. Moldboard tillage and fallow-sugarbeet-wheat rotation reduceddensity ofgrassseeds than on-tillage system andrapeseed- fallow-wheat rotation19 times. Use cultivator established the lowest species richnessIn 20-30 depth with 0/06 and the greatest diversity in 0-10 depth with 2/38. Lowest and highest Simpson species evenness index also observed at20-30 depth and using minimum tillage system with0/48 and 0-10 depth with 1/26 respectively.