Effects of Tillage Methods and Rates of Corn Residues on Wheat Growth, Yield and Yield Components

In order to evaluate the effects of tillage methods and rates of corn (Zea mays L.) residues on yield and yield components of wheat (Triticum aestivum L.), a two-year (2008-2009) field experiment was conducted at Agricultural Research Station, Shiraz University (Badjgah), Shiraz, Iran, with the split plot design arranged in randomized complete blocks with four replications. Treatments were tillage methods [conventional (moldboard plow with two harrow disks) and reduced tillage (two chisel plow with one harrow disk)] as main plots and corn residues rates (0, 50 and 100%) as subplots. The results showed that tillage methods had significant effects on ears number per m2, and rates of crop residues on grains per ear, 1000-grain weight and plant height in both years. The highest grain yield (4.40 t ha-1) was obtained when the residues were completely removed and reduced tillage method was used, with no significant difference with 100% crop residues. Increased crop residues rates in reduced tillage method increased soil organic carbon (SOC) and nitrogen. In general, application of appropriate rates of crop residues to increase SOC, is recommended. If it could persist short terms yield reductions, it will achieve desirable yield in long terms