Abstract
The study was conducted at the Agricultural Research Station, Bangladesh Agricultural Research Institute, Bogra, for three chickpea growing seasons from 1998 to 2001. The objectives of the study were to identify the most suitable technologies with respect to soil moisture conservation and better yield of chickpea and to find out various interaction effects among tillage, mulch, irrigation, sowing date and seeding depth on the growth and yield of chickpea. The results revealed that adoption of medium or fine tilth and black polythene or straw mulch was the most effective technique for soil moisture conservation of the site characterized with low organic matter and low water holding capacity. Seed yield was higher with medium and fine tilth than that of coarse and minimum tilth in 1998-1999 while it was also higher with medium tilth in the following year. Improvement in tillage up to medium tilth significantly increased the seed yield over minimum tilth in different years. Both black polythene and straw mulches had positive effects on seed yield over no-mulch and other mulching techniques. The physiological parameters like LAI, DM, CGR and RGR were also significantly higher in medium tilth or fine tilth and in black polythene mulch or straw mulch. White polythene mulch reduced seed yield remarkably as this practice raised the maximum soil temperature by 5.03 °C to 8.09°C than no-mulch while in case of black polythene mulch the rise in soil temperature was negligible, only 0.09 °C to 2.15°C. Straw mulch reduced the maximum soil temperature by 1.96°C to 5.88°C over no-mulch. The application of irrigation singly or in combination with black polythene mulch or straw mulch increased the seed yield. Two irrigations failed to give any significant yield advantage over one irrigation. The crop performed better when sown either on 8 November or on 15 November in respect of seed yield and plant characters. The crop sown on 8 November or 15 November in combination with black polythene mulch or straw mulch gave significantly higher seed yield than any other sowing dates irrespective of mulches, the yield was 225% to 237% higher compared to 22 November sowing without mulch. These two sowing dates with black polythene mulch or straw mulch in combination with 7.5 cm or 10.0 cm seeding depth gave similar yields but it was significantly higher than that of any other sowing dates in any combination of mulch and seeding depth. The crops grown with one irrigation x medium tilth x 15 November sowing, one irrigation x fine tilth x 15 November sowing, two irrigations x fine tilth x 15 November sowing, two irrigations x medium tilth x 15 November sowing gave significantly higher yield over no- irrigation x minimum tilth x 30 November sowing or no-irrigation x minimum tilth x 31 October sowing. The findings evidenced that the most effective technology among the moisture conservation means under study for achieving higher yield of chickpea was sowing seeds on 8 November or 15 November with soil of medium tilth under black polythene mulch or straw mulch at seeding depth of 7.5 cm or 10 cm.