Upgrading a Conventional Row Crop Planter to a Direct Seeding Machine for Planting of Corn in Conservation FarmingSystem

摘要

Direct planting of corn following wheat is faced with problems in arid and semiarid zones. Soil stiffness as a result of high evaporation and heavy surface residue do not allow furrow openers penetrate desirably in the soil. In this research effects of active toothed coulter on planter penetration in such soils were studied. First a toothed coulter equipped with hydro motor was fabricated and mounted on a conventional pneumatic row-crop planter. Then effects of three levels of speed ratio (coulter peripheral speed/tractor forward speed; 1.2, 2, 3) at two previous residue levels (baled-out and non-baled) and two modes of planter attachment (with and without row cleaner) on the planting depth and its uniformity, emergence rate index, amount of surfaceresidue after planting and seed spacing indices (multiple, miss, quality of feed and precision) were investigated. Results showed that planting depth and its uniformity increased with increasing of speed ratio significantly, where at speed ratio of 2, desired planting depth (5 cm) was obtained with maximum uniformity. The emergence rate index increased with increase in speed ratio mainly due to increase in seeding depth at higher speed ratios. Maximum value of emergence rate index was obtained at speedratio of 2. The active toothed coulter decreased miss and precision indices mainly due to decrease in amount of surface residue which is desirable. Planting with row cleaner into baled-out residue plots at speed ratio of 2 resulted in 31% decrease in miss and 33% decrease in precision indices. The quality of feed index values as high as 70% were obtained at similar conditions, the increase was up to 11% as compared to control.