Influence of minimum tillage systems on the control of Convolvulus arvensis L. on wheat, maize and soybean

Convolvulus arvensis L. causes special problems because of its ability to reproduce both through seeds but particularly through vegetative propagation, and also because it’s relative tolerance to numerous herbicides. Extending new tillage systems, conservative systems specific to conservative sustainable agriculture, is a difficult task to accomplish under the circumstances of strong dicotyledonous perennial weed infestation. C. arvensis is one of the most dangerous perennial dicotyledonous weeds when applying minimum tillage systems. A research was conducted in the pedoclimate of Cluj-Napoca, Romania, investigating the control of C. arvensis by minimum tillage. The goal was to determine the relationship between soil tillage system and herbicide on wheat, maize and soybean. Except for the soil tillage system, all other variables were held constant for a 3-year crop rotation. The use of minimum tillage systems caused, at the end of a 3 year crop rotation, the increase of the C. arvensis pervasion in all three crops: 11.2-39.1% for soybean, 0.9-4.2% for wheat, and 11.9-24.4% for maize. The occurrence of C. arvensis seeds in the soil increased to 169% under the disk + rotary harrow minimum tillage system, with 77% of those seeds located in the upper 10 cm of the soil profile. Total weed density was significantly lower under the conventional tillage than under the minimum tillage system. Related to conventional soil tillage system, the productions registered in minimum tillage system represented 93-99% in wheat, 89-97% in maize and 103-112% in soybean. The main benefit of the conventional tillage is a highly important decline of perennial weeds.