Abstract
Field experiments were conducted at the Regional Agricultural Research Station. of the Bangladesh Agricultural Research Institute, Jessore during rabi seasons of three consecutive years (1998-1999, 1999-2000 and 2000-2001) to evaluate the effect of different tillage and mulch practices on the conservation of residual soil moisture and crop yield. Three tillage practices viz., minimum, reduced and conventional tillage and three mulch practices eg., rice straw, water hyacinth and black polythene along with no mulch (control) were assigned as treatment variables. The selected crops were mustard. chickpea, wheat and barley. The experiment was laid out in a split-plot design distributing the tillage treatments to the main plots and mulches to the sub-plots. The parameters under study were soil moisture, soil temperature, plant growth characters (dry matter accumulation, leaf area index, crop growth rate and root dry matter), crop yield (seed/grain yield and straw yield) and seed/grain protein content. Black polythene mulch produced the highest leaf area index (LAI), crop growth rate (CGR), grain yield and harvest index followed by straw mulch. Reduced tillage produced significantly higher biological yield of mustard and wheat as compared to minimum tillage. In case of chickpea, both reduced and conventional tillage and for barley, the conventional tillage resulted in markedly higher seed/grain yields in comparison with the other tillage practices. The minimum tillage gave significantly lower yield possibly due to reduced root growth coupled with lower nutrient uptake. The reasons for the best yield performance of black polythene mulch can be attributed to efficient soil moisture conservation for cool soil temperature. Variation in yield was also noticed between years, higher yield being in 2000-2001 than in 1999-2000 which can be explained by higher soil moisture for rainfall foccurring in 2000-2001. Overall results indicate that polythene mulch or rice straw accompanied by reduced tillage can be suggested as an efficient practice in order to conserve soil moisture for higher yield.