Influence of Soil Tillage System on Agropyron repens and Cirsium arvense Crop Weed Growth

The objectives of research are as follows: establishing the influence of soil tillage method on weed growth in corn crop; establishing the influence of soil tillage method on weed growth in soybean crop; establishing the influence of soil tillage method on weed growth in wheat crop; determining the evolution of weed growth under the influence of a soil tillage system during the three years corn-soybean-wheat crop rotation; establishing the influence of weed growth of couch grass on corn, soybean and wheat crop production; establishing the influence of weed growth of couch grass on corn, soybean and wheat crop production; establishing the influence of weed growth of creeping thistle on corn, soybean and wheat crop production. Results concerning the corn crop, considering the ploughed tillage system as control variant, all the other 3 systems (paraplow, chisel and direct sowing) gave crop yields between 4355 and 5082 kg /ha, with very significant negative differences, with limits between 984 and 1274 for paraplow and chisel, respectively 2001 kg /ha for direct sowing. The weed growth in soybean crop depending on soil tillage system is confirmed by a variation of weeds number/m2 from 94 (in variant worked with plough) to 157 (in direct sowing variant). Based on the registered data, we can estimate an increase by 30.85% of weed growth in paraplow variant, respectively by 138.29% in chisel variant, compared to variant plough worked soil. The 31 - 38% increase in the unconventional variants paraplow and chisel is significant and imposes a change of weed control strategy, due to the pronounced early start of weed growth which will have an influence on soybean crop production. Soil tillage system applied on wheat crop influence on weed growth emphasize a different degree in weed growth depending on tillage system; thus, compared to witness variant with plough, where 85 plants/mp were identified, in chisel and paraplow working systems the number of weed plants range between 104 - 105, meaning an increase with 22 - 24%. In the case of direct sowing, the weed growth degree is the highest, reaching 141 plants/mp, meaning an increase with 65.88%.