Effects of different tillage techniques on some soil properties and sunflower yield in dryland conditions of Shahrood (Miami)

In order to study the effects of various tillage methods on some soil physic-chemical properties, soil moisture maintain and sunflower performance, in Kalpoush dryland region of Miami, this project conducted as Randomize Complete Block Design (RCBD) with four replications in wheat rotation. Treatments were included, 1- moldboard plowing + disk harrow (CT), 2- reduced tillage with disk harrow (RT1), 3- reduced tillage with chisel plowing (RT2), 4- reduced tillage with chisel packer (RT3) and 5- direct seeding or no-tillage (NT). The results showed that at depths of 0-15 cm, soil moisture storage in conservation tillage was higher than the conventional tillage (P<0.05). In the first and third years of the experiment, in the conventional method, compared with the no-tillage, the yield of sunflower was higher. In the final year (2016), the result was reverse. Combined analysis of 3-years on sunflower yield showed that conventional tillage and direct seeding were in the same class. In low precipitation year (2016), sunflower grain yield decreased in the conventional method but it increased a little in direct seeding method. In addition, soil moisture saving and precipitation use efficiency in direct cultivation was more than conventional method. Results of research showed that, after several years, grain yield of the sunflower has increased in conservation method and this may be an appropriate alternative to the conventional tillage method.