Abstract
The final yield of agricultural products depends on the effective factors during the growing season of plants, especially the size of soil aggregates and proper size distribution of aggregates. Therefore, it is very important to select appropriate tillage implement and to provide a suitable seedbed in terms of aggregate size with the least energy consumption. It is a new idea to use paraplough and winged-paraplough as tools for seedbed preparation. To measure and determine the factors affecting the mean weight diameter (MWD) of aggregates and percentage of crop residues on the soil surface, a series of field trials were performed in a randomized complete block design (RCBD) with five replications. The trials were conducted at three forward speeds of 2, 5 and 7 km·h−1 and three operating depths of 0–10; 0–20; 0–30 cm using the mouldboard plough and the paraplough with different wing configurations (without wings, with forward wings, with backward wings). The main impacts of implemented type, forward speed and operating depth and their mutual binary effects were significant at P <1% for both the MWD of aggregates and percentage of remaining residue. The highest MWD of aggregates was related to mouldboard plough (5.59 mm) and the lowest value was related to paraplough with backward wings (2.9 mm). It was found that the winged paraplough created a good pulverization in the soil and sustained a high percentage of crop residues on the soil surface. This issue can be very useful and important in the conservation tillage and the conservation of soil resources, especially in the water deficient areas where the soil is prone to erosion.