EFFECT OF TILLAGE WITH CHISEL PLOW ON SOIL MEAN WEIGHT DIAMETER AND POROSITY

Abstract

An experiment was conducted to evaluate the effect of speed, depth of tillage and removing the standard weights from the New Holland TD80 tractor on mean weight diameter and the total percent of soil porosity. The experiment was carried out in silty clay loam soil on a farm of College of Agric. / Baghdad University in 2010. Three levels of speed included 3.21, 5.37, 7.04 km/h which represented the main plots ,two levels of weights included standard weights and removing standard weights which represented the sub plots, and three levels of depth included 10, 15 and 20cm which represented the sub – sub plots were used in this experiment . The experiment was designed according to a split-split plot arrangement in a randomized complete block design with three replications. The results showed that increasing tillage speed for the machinery unit from 3.21 to 5.37 and to 7.04 km/h caused significant decrease in mean weight diameter and soil porosity with decrease ratio 4.26%, 2.30% for mean weight diameter and 2.7%, 1.7% for soil porosity. The addition of weights caused a significant decrease in mean weight diameter and porosity with decrease ratio 2.39% and 1.76% respectively. The results also showed that Increasing tillage depth from 10 to 15 and to 20 cm caused a significant increase in mean weight diameter with increase ratio 7.37% , 7.86% , and significant decrease in soil porosity with decrease ratio 4.34%, 5.42% . the conclusion for this research showed that the Increasing tillage speed for the machinery unit (chisel plow and New Holland TD80 tractor) and weights addition to the tractor rear wheel caused significant decrease in mean weight diameter and soil porosity.