Effect of tillage methods and corn residue management on wheat yield and weed control in Zarghan region of Fars province

To evaluate the effect of different tillage methods (CT: conventional tillage, RT: reduced tillage, and NT: no-tillage), and residue management of corn on species diversity, density and dry weight of weeds, as well as yield and yield components of wheat, a 3-years trial was conducted using a split-plot experiment based on a randomized complete block design (RCBD), with three replications during 2014-2017 at the Research Center of Zarghan, Fars Province, Iran. Results showed that species diversity of weeds was affected by tillage methods and residue management, so that conservation tillage especially RT method decreased 30% of weed infestations. Over time, applying NT method increased perennial weed density, while CT and RT methods accompanied by residue retention reduced 60% of perennial weed density compared to NT method. Applying RT method and residue retention maximized grain yield of wheat (8113 kgha-1) up to 30% compared to residue removal. The highest harvest index (40.26%) was obtained by CT method and residue retention, but the maximum 1000-grain weight (40.18 g), grain number per m2 (20827 seeds), and biological yield (20084 kgha-1) were achieved by RT method and corn residue retention. In general, adopting RT bill age method and retaining 30% of corn residue is recommended for wheat-corn cropping system in fars provience.