Irrigation requirement of transplanted monsoon rice in Bangladesh

摘要: Abstract The main rice crop of Bangladesh is grown in the monsoon season as a transplanted rainfed referred to T. Aman. Yields are often low because late-season water stress associated with rainfall variability and late planting. To realise yield potential modern varieties, control, including supplemental irrigation, needs be improved. Using daily water-balance simulation technique on cropping system pre-monsoon (Aus) followed by irrigated Aman, this study estimates for representative stations 24 districts probable planting dates irrigation required avoid significant deficit during reproductive phase Aman crop. results presented isolines country map, it concluded that throughout optimal performance. requirement period increases from 0 mm Northeast 225 Northwest, neglecting seepage distribution losses. Some implications small-scale harvesting method discussed. Thus, application losses, 2 m deep ditch an area equal 5% satisfy intermediate, field 100 infinitly large areas. pond/land ratio 15% smaller areas pyramidal-shaped pond side slope requirements stability. Economic sustainability requires should less than 9%, limiting 180 depth more 1.1 m. In Western part, therefore likely uneconomical shallow ponds small non-clay soil unless additional benefits derived pond.