The Effect of Conventional and Conservation Tillage Methods on the Improvement of Wheat Yield in Different Planting Dates and Seeding Rates

Production in areas under rainfed cultivation is always associated with different constraints that among them, changes in precipitation and air temperature from year to year are widespread and uncontrollable. In this regard, the current study was conducted in order to compare conservation and conventional tillage methods on wheat yield in sowing dates before and after effective autumn rainfall. The experiment was carried out as split-split plots based on a randomized complete block design with 3 repetitions in two years 2018 to 2020. Experimental treatments included planting time as main plots with two levels D1= before rainfall and D2= after rainfall tillage method as sub-plots including T1= conservative and T2= conventional and seeding rate as sub-sub-plots including S1= 200, S2=300 and S3= 400 seeds. The results demonstrated that although the planting date and seeding rate had no significant effect on the studied traits, the values obtained from the cultivation before rainfall and under 300 and 400 seeding rates were remarkably better. Tillage method caused a significant difference in grain yield and biomass of treatments 3634 and 8394 kg. ha-1, respectively, whereas conventional tillage the values were 2819 and 6114 kg. ha-1. Conservation tillage and cultivation before rainfall associated by using 300 seeds/m2 led to the highest values in number of plants, spikes, and 1000-grain weight compared to conventional method and cultivation before rainfall. Consequently, considering the cost of production, pre-autumn rainfall sowing under conservation tillage and with a 300 seeds/m2 is recommended for Gachsaran region.