Performance evaluation of a light tractor during plowing at different levels of depth and soil moisture content

ABSTRACT: In this study, the tractive performance of a light tractor (25.8 KW) for 2-bottom moldboard plowwere measured in three soil moisture content ranges of (16-18%,19-22% and 23-25%db) and three different depths (10,15 and 20 cm) in a silty-clay soil. The measured and calculated parameters were: rolling resistance, wheel slip and tractive efficiency. Data were analyzed in a randomized complete block design with three replications. During the tests the forward speed was kept constant at about 3.7±0.15 kmh-1. The results indicated thattillage depth and soil moisture contenthad a significant effects (P < 0.01) on the tractive efficiencyand wheel slip. Also, the effect of moisture content on rolling resistance was significant (P < 0.01). Interaction effect of depth and moisture content on rolling resistance and wheel slip at 5% and 1% level of probability were significant, respectively. Mean comparison of tractive efficiency with Duncanʹs multiple range test showed that the tractive efficiency was the least at higher depth and moisture content. Tractive efficiency of tractor was over 46% at shallow plowing and decreased up to 41% with increasing plowing depth. Amount of wheel slip increased from 11.91% up to more than 29.47% by increasing of depth plowing from 10 to 20cm. The overall results of this study showed that light tractor had not desirable tractive efficiency at shallow plowing and it is suitable for medium plowing (15-20 cm).