Effects of Tillage Method, Drainage Management and Temporal Variability on Some Soil Physical Properties and Organic Matter

Abstract

Tillage is one of the most important practices affecting soil physical and hydraulic properties. Its effects may vary intensely according to the tillage method. This study aims to evaluate the effects of tillage methods (B1: moldboard plow+disk harrow, B2: moldboard plow+rotary tiller and B3: chisel plow+disk harrow), drainage (A1: subsurface drainage and A2: non-drainage) methods and temporal variability (T1: after planting and T2: after harvesting) on physical properties and organic matter of a clay loam soil under winter-wheat crop. The experiment was conducted in split-plot in time statistical design. Soil bulk density, soil particle density, aeration porosity, aggregate mean weight diameter (MWD), saturated moisture content and water infiltration rate were determined at two different times of T1 and T2. Results revealed that the tillage method had significant effect on organic matter content, such that the highest (1.35%) values were observed in chisel treatment. Tillage effect was significant on saturated moisture content, MWD, aeration porosity and infiltration rate. The effect of time was significant on all investigated factors. The effect of drainage was significant on MWD and infiltration rate. Evaluating the effects of tillage and drainage indicated that the contribution of drainage on changing MWD is higher than the tillage methods. Further, in non-drainage condition, the tillage method had a significant effect on aeration porosity (P<0.05), so that moldboard plow makes much more aeration porosity (25.48%) compared to chisel (17.17%). Conversely, the MWD of moldboard plow (2.4 mm) was significantly lower than that of chisel (2.8 mm), in non-drainage conditions (P<0.05). According to the result, the lowest and highest values of MWD were obtained in the treatments of A1B1 and A2B3, respectively. The application of chisel is not recommended in no-drained areas having high level groundwater, because of the highest saturated moisture content and MWD along with the lowest aeration porosity compared to moldboard plow.