Tillage and mulch effects on some soil physical properties and yield of wheat in shallow red brown terrace soils of Bangladesh.

摘要

Field experiments were conducted at the farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur, Bangladesh during two consecutive rabi (winter) seasons of 2000/2001 and 2001/2002 to determine the tillage and mulch effects on physical properties of shallow red brown terrace soils, using wheat as the test crop. Laboratory investigations were also carried out to analyse these properties. The physical properties of the soil were markedly influenced by tillage and mulch. Bulk density was significantly altered by different tillage practices wherein the lowest bulk density was observed in disc ploughing at 0-10 cm soil depth. The lowest value of soil strength was recorded in the ploughed zone of disc and chisel ploughing and the highest values in minimum tillage. Mulch had less effect on bulk density and soil strength. Polyethylene mulch showed the highest temperature and the lowest was observed under straw mulch. Minimum tilled plots showed the maximum level of soil temperature at 10 cm depth all through the day. Similar trend in results was also observed for weekly mean soil temperature. Cumulative infiltration and infiltration rates were higher in disc and chisel ploughing and lower in minimum and conventional tillage methods. Disc ploughing and rice straw mulch significantly increased grain and straw yield of wheat. Average grain yield increases over minimum tillage were 13% with conventional tillage, 23 and 20% with disc ploughing and chisel ploughing, respectively. Similarly grain yield increases over no mulch were 23, 18 and 11% with rice straw mulch, water hyacinth and polyethylene mulch, respectively..