Effects of tillage systems on soil properties, fuel consumption,and wheat yield in the wheat-sesame rotation

Despite the relatively long history of conservation tillage in the world, this technology is still new in Iran; therefore, evaluating effects of conservation tillage on soil properties and crops yield is necessary. Thus, this study was conducted using a randomized complete block experimental design with five treatments and four replications in Darab region of Fars province for four years (2010-2014). Treatments were T1) reduced tillage with 15 cm tilling depth, T2) wheat and sesame direct seeding, T3) sesame direct seeding for four years, wheat direct seeding for the first two years and the fourth year, and conventional planting in the third year, T4) wheat direct seeding for four years, sesame direct seeding for the first two years and the fourth year, and conventional planting in the third year, and T5) conventional tillage using moldboard plough (tilling depth of 25 cm), disk harrow, and land leveler. Soil moisture content, soil aggregates, soil bulk density, percentage of residue inversion, fuel consumption, field capacity, and wheat yield were measured. Results showed that conservation tillage methods increased soil moisture content by up to 18%, but soil bulk density was not affected by tillage methods. Conservation tillage methods decreased fuel consumption compared to the conventional tillage by up to 77% and increased effective field capacity for seed bed preparation and planting for up to 2.8 times. Wheat yield significantly decreased in the conservation tillage methods compared to the conventional tillage by 21%; therefore, soil needs more time to get adapted to the conservation tillage conditions in Darab region. Economic evaluation also showed that conventional tillage was the first option for the seed bed preparation in the wheat-sesame cropping system in Darab region, and the reduced and no-till were the second and third priorities, respectively.