effect of tillage method and rice cultivation on machine parameters, yield and yield components of wheat and residue management for rice-wheat rotation in khuzestan

paddy rice residue covers more than 60000 ha of the khuzestan plain. high soil moisture content (low evaporation and heavy soil texture), time limitations, and the likelihood of rainfall make conventional tillage methods unsuitable for wheat cultivation after the rice harvest. the present study investigated the best residue management method, and fuel and time savings, to produce acceptable yields and improve the physical properties of the soil. the study was conducted on silty-clay soil from 2010-2012 at shavoor agricultural research station in northern ahwaz province in iran. testing was conducted in strip plots using a randomized complete block design with three replications. the main plots were tillage method: t1 = conventional plow + disc harrow + leveler; t2 = chisel plow + disc harrow + leveler; t3 = chisel plow + rotavator; t4 = disc harrow + rotavator; t5 = two passes of disc harrow + leveler; t6 = one pass of rotavator; and t7 = no tilling or drilling. subplots combine two rice residue cover varieties (ld183 and anboory) with two rice-growing methods (paddling and dry seeding). the results showed that the highest (49.1 l/ha) and lowest (20 l/ha) fuel consumption were recorded for t1 and t7, respectively. fuel consumption decreased 35% for t2, 20% for t3, 31% for t4, 50% for t5, 44% for t6, and 59% for t7 over t1. t1 at 4.3 h/ha and t7 at 0.5 h/ha had the highest and lowest total operation times, respectively. total operational time decreased 46% for t2, 35% for t3, 39% for t4, 70% for t5, 53% for t6, and 88% for t7 over t1. total operational cost of conservation tillage methods decreased 20% to 33% over t1. type of rice residue and rice growing method had no significant effect on wheat grain yield or on other parameters. there was a significant difference between tillage methods versus seeding depth and soil versus residue break-up. wheat grain yield for the first year of testing was significant and 9.6% higher than for the second year. the results for sowing wheat after rice harvest in silty-clay soil in khuzestan province using available machinery recommends tillage methods t7, t5, t2 or t6 instead of conventional method t1.