Investigation of the Effect of Speed, Depth, and Type of Tillage on Soil Surface Roughness and Burial of Plant Residues in Rainfed Lands

The presence of soil surface roughness and plant residues can slow down the erosion process, particularly on rainfed fields. The aim of this study was to select the most suitable tillage method, which has the highest soil surface roughness index and the lowest rate of the burial of plant residues. Three factors of plowing machine (Moldboard-plow, Moldboard-plow + Disc harrow, Disc plow and Chisel plow), speed (3, 5 and 7 km/h) and tillage depth (15-20 cm and 25-30 cm) were evaluated in a factorial experiment in a completely randomized design. The soil surface roughness was measured using a pin-meter. Image processing techniques were used to determine the percentage of burial of plant residues. The results showed that the effect of all main factors on the soil surface roughness index was significant and the highest and lowest roughness indices were related to moldboard plow (12.8cm) and Moldboard plow+Disc harrow (3.6cm), respectively. In addition, Chisel plows and Disc harrow+Moldboard plow treatment showed the lowest and highest rates of plant residue burial of 29.3% and 92.9%, respectively. Taking into account the results, chisel plow can be selected as the most suitable tillage method in terms of soil protection against wind and water erosion.