Effect of cover crops residue on weed control and yield in conservation tillage tomato (Lycopersicon esculentum Mill.) production

It has been proved that cover crops combined with minimal or no till in tomato production reduce weed pressure and simultaneously slow down soil erosion, conserve soil organic carbon, and improve soil fertility. Therefore, a study was conducted to evaluate the interaction effects of cover crops including legumes, (Vicia villosa Roth and Vicia sativa L.), and legumes mixed with grasses (Secale cereale L. and X Triticosecale Wittmack), and cover crop biomass management (incorporation of residues into soil, strip tillage and no tillage) on weed control, tomato yield, nitrogen level of tomato leaf and soil, and soil organic carbon for 2 years. Generally, cover crops reduced weed dry weight in all tillage systems, and increased tomato leaf N level compared to that of conventional methods, but soil N and organic carbon contents were not affected throughout the experiments. In 2017, the highest tomato yield (40.5 and 41.1 t ha(-1)) was recorded in legumes and mixed legumes-grasses treatments with no-till management, respectively. However, in 2018, the tomato yield decreased about 41% in the latter treatment. Totally, legume treatments in incorporation residue into soil and no-till systems with 61.3 and 61.2 t ha(-1), and mixed legumes-grasses treatments in strip-till system with 62.2 t ha(-1), respectively, had the highest tomato yield compared to that of other treatments. It seemed legumes-grasses treatment in the strip-till was generally more advantageous over the no-till. Based on results, to make possible no-till in vegetable systems, cover crops should provide an appropriate seedbed for tomato roots in the soil.