Evaluation of the possibility of Surface Tillage in Irrigated Wheat

Every year the degradation of agricultural soil is increasing due to improper tillage operation. The main objective of this study is evaluation and comparison of surface and conventional tillage methods by measuring the wheat yield and its components.This study is conducted in three consecutive years with two treatments and four replications. Conventional tillage method includes: moldboard plow, disk harrow, leveler, following by chemical fertilizer and planting with grain drill. Surface tillage method includes: disk harrow in the depth of 6-8 cm after removing of residual, disk harrow in the depth of 12-15 cm in fall, spike tooth harrow, following by chemical fertilizer and planting with grain drill. Analysis of variance were conducted with a complete randomize block design. Results show that conventional tillage is better than surface tillage in grain yield, number of heads in unit area, number of grain in the head, weight of 1000 seeds, weight of straw and harvesting index. A significant difference was observed between treatments in some areas. The average wheat yield in conventional tillage was 315 kg more than the yield in surface tillage. This difference might be due to higher plowing depth and better residual burring with moldboard plow. The grain yield in surface tillage was 92% of the yield in conventional tillage. Conventional tillage consumes more energy comparing to the surface tillage and it takes more time and causes more depreciation of the implements and the cost will increase. This necessitates more study. Since the farmers in Iran cultivate two times a year, the time for preparing soil and cultural practices for the second cultivation is short. With consideration of less time being needed for soil preparation in surface tillage and no difference in the yield in the two methods, the surface tillage is recommended in irrigated wheat in Iran