Effect of Tillage Methods on Soil Physical Properties and Water Productivity of Wheat Cultivars in Wheat-Corn Rotation

This research is based on the results of a study that was carried out to evaluate the effect of direct drilling of wheat in maize residues on yield and water productivity (WP) for two years of 2016 and 2017. For this purpose, a field experiment was conducted as split plots with a randomized complete block design with three replications in Safiabad Agricultural Research Center located in Dezful, north of Khuzestan province. The main plot treatments were including: No-Tillage (NT), Minimum Tillage (MT), and Conventional Tillage (CT) and sub plots treatments were Chamran 2, Mehregan, Shoosh, Falat, and Darab 2 cultivars. The results showed although there was no significant difference between tillage methods, but the average yield of cultivars in the NT (4830 kg ha-1) was more than the MT (4610 kg ha-1) and CT (4680 kg ha-1). On the other hand, the average yield and WP of both Mehregan and Chamran2 cultivars (5000 kg ha-1 and 1.25 kg m-3,respectively) were more than the other cultivars. Although in this research, reducing passes of tillage and planting machinery from 6 to 7 times in MT and CT to only 2 times in NT method (chemigation and planting in maize residues) did not have a significant effect on the soil cone index and soil bulk density, the soil organic carbon increased 16 to 32 percent in NT method in comparison to other tillage methods. Therefore, the use of new wheat cultivars under direct drill planting conditions in maize residues without yield reduction and 3-4 percent WP improvement is recommended in similar areas.