Abstract
A field and laboratory experiment was conducted during 2000-2001 and 2001-2002 to estimate the tillage and mulch effects on physical properties of soil. The experiment was laid out in split-plot design with three replications. Four different tillage methods were used in the main plots: minimum tillage (MT), conventional tillage (CT), disc ploughing (DP) and chisel ploughing (Chp), and four different mulch treatments were used in the sub-plots including rice straw mulch (RSM), water hyacinth mulch (WHM), white polyethylene mulch (WPM) and no mulch (NM). The physical properties of the soil were markedly influenced by tillage and mulch. The bulk density was significantly altered by different tillage practices. The lowest bulk density was observed in disc ploughing at the 0-10 cm-soil depth. The lowest value of soil strength was recorded in the ploughed zone, which used disc and chisel ploughing, and the highest values came from area of minimum tillage. Mulch had less effect on bulk density and soil strength. Marked differences in weekly mean and diurnal soil temperature under different mulch practices were observed. Polyethylene mulch showed the highest temperature and the lowest was observed under straw mulch. It was observed that minimally tilled plots showed the maximum level of soil temperature at the 10 cm depth throughout the day. Similar trends in the results were also observed for weekly mean soil temperature. The cumulative infiltration and infiltration rates increased with pulverization of soil and increasing depth of ploughing. Cumulative infiltration and infiltration rates were higher in disc and chisel ploughing and lower in minimum and conventional tillage methods.
