Effect of Tillage Depth and Speed on Top Soil Physical and Hydraulic Properties

In order to evaluate the effect of tillage depth and speed on soil physical and hydraulic properties, this research was performed in a clay loam soil. Moldboard plow treatments in three replications were employed in a completely randomized block design with a split tape according to both speed and depth of tillage. Infiltration of soil was determined in undistributed samples by using disc infiltrometer apparatus under -15, -6, -3 and 0 cm H2O suctions (K15, K6, K3, Ks). The results revealed that the tillage speed had significant effect on K3 and Ks at 5% and 1% probability level, respectively, whereas deep tillage as well as interaction of the factors did not affect them. Both of the studied factors (depth and speed) and their interaction had no significant effect on K6 and Gardener α coefficient, while they had significant effect on the bulk density of top soil at 5% probability level. Furthermore, K15 showed significant differences under the effect of tillage depth at 5% probability level. The results also indicated that speed of tillage had no effect on the bulk density of sub-surface layers.