Agricultural land use and distribution of cultivated crops expressed in cropping pattern (CP) constitute the base for increasing produtivity. An in-depth study was conducted on the existing CPs of Bangladesh in each and every upazila (sub-districts) using semi structured questionnaire and data validation by the stakeholder consultation workshop conducted in each of 64 districts. Three hundred and sixteen CPs were identified throughout Bangladesh excluding the very minor ones. Topmost five CPs were only rice containing CPs, which covered 51% of the net cropped area. The most dominant CP was Boro- Fallow-T. Aman covering 27% of net cropped area. Results on major cropwise CPs, location-wise CPs, CP diversity and crop diversity etc are also presented herein.Bangladesh Rice j. 2017, 21(2): 1-55

South Asian countries will have to double their food production by 2050 while using resources more efficiently and minimizing environmental problems. Transformative management approaches and technology solutions will be required in the major grain-producing areas that provide the basis for future food and nutrition security. This study was conducted in four locations representing major food production systems of densely populated regions of South Asia. Novel production-scale research platforms were established to assess and optimize three futuristic cropping systems and management scenarios (S2, S3, S4) in comparison with current management (S1). With best agronomic management practices (BMPs), including conservation agriculture (CA) and cropping system diversification, the productivity of rice- and wheat-based cropping systems of South Asia increased substantially, whereas the global warming potential intensity (GWPi) decreased. Positive economic returns and less use of water, labor, nitrogen, and fossil fuel energy per unit food produced were achieved. In comparison with S1, S4, in which BMPs, CA and crop diversification were implemented in the most integrated manner, achieved 54% higher grain energy yield with a 104% increase in economic returns, 35% lower total water input, and a 43% lower GWPi. Conservation agriculture practices were most suitable for intensifying as well as diversifying wheat-rice rotations, but less so for rice-rice systems. This finding also highlights the need for characterizing areas suitable for CA and subsequent technology targeting. A comprehensive baseline dataset generated in this study will allow the prediction of extending benefits to a larger scale.

a b s t r a c tIn the Eastern Gangetic Plains of Bangladesh, the cropping systems are predominantly rice based, having large yield gaps in farmers' fields because of poor management practices adopted by farmers. The increasing scarcity of resources (water, labor and energy) and production costs further make the ricebased cropping system less sustainable and less profitable. We hypothesized that integrating the best compatible cropping patterns accompanied by best management practices into the portfolio of farmers' own technologies would improve system productivity, resource use efficiency and economic profitability. To test this hypothesis, we evaluated four cropping system scenarios (S1-S4) designed to be adapted to current and future drivers of agricultural changes and varying from each other in best management practices (BMPs) and conservation agriculture (CA) principles (tillage and crop establishment, residue management, and crop rotation). Four cropping system scenarios were (i) current farmers' practice (S1), (ii) BMPs with conventional tillage and farmers' crop rotation (S2), (iii) BMPs with reduced tillage and farmers' crop rotation (S3), and (iv) BMPs with reduce or zero tillage and crop diversification (S4). Scenario 2 alone compared with S1 increased system productivity (24-33%), total water productivity (16-50%) and net economic returns (85-169%), and decreased specific energy (11-17%). The combination of BMPs in S2 with reduced tillage and manual or mechanical transplanting (S3) did not further increase yield and save water. Crop diversification with potato in place of Boro rice and intensification with maize or mungbean in between Boro and Aman rice (S4) yielded 1.9-3.7 times higher net economic returns than S1. Results of a three-year study indicated that farmers' productivity and economic returns can be improved by BMPs, which not only increase crop yields but also improve the efficiencies of resources such as water and energy.

Towards the sustainable food security for a particular area, the policymakers, researchers, extension and development agents need the detailed information of cropping patterns, cropping intensity and crop diversity. Sylhet, a potential region of enormous potentiality of growing crops across the haor area lying below the northeastern Himalyan foothills experience the highest rainfall in the world to make the basin prone to flashflood. That is why, a study was conducted in the region considering all the upazillas during 2016 using the pretested semi-structured questionnaire and validated by appropriate informants with a view to documenting the existing cropping patterns, cropping intensity and crop diversity in the region. As per the study the region is dominated by the rice based cropping pattern. The non-rice based cropping pattern are either few or the area under those cropping patterns are not enough to satisfy the non-rice food requirement of people of the region. Beside these, the cropping patterns and crop diversity appeared as below the expected level. Therefore, much thrust is needed to initiate research and development activities to diversify the single or double-cropped cropping pattern with the introduction of appropriate crops and crop varieties even other non-crop agricultural commodities.Bangladesh Rice j. 2017, 21(2): 273-288

The study was conducted over all 42 upazilas of Chittagong region during 2016 using pre-tested semistructured questionnaire with a view to document the existing cropping patterns, cropping intensity and crop diversity in the region. The most dominant cropping pattern Boro−Fallow−T. Aman occupied about 23% of net cropped area (NCA) of the region with its distribution over 38 upazilas out 42. The second largest area, 19% of NCA, was covered by single T. Aman, which was spread out over 32 upazilas. A total of 93 cropping patterns were identified in the whole region under the present investigation. The highest number of cropping patterns was 28 in Naokhali sadar and the lowest was 4 in Begumganj of the same district. The lowest crop diversity index (CDI) was observed 0.135 in Chatkhil followed by 0.269 in Begumganj. The highest value of CDI was observed in Banshkhali, Chittagong and Noakhali sadar (around 0.95). The range of cropping intensity values was recorded 103−283%. The maximum value was for Kamalnagar upazila of Lakshmipur district and minimum for Chatkhil upazila of Noakhali district. As a whole the CDI of Chittagong region was 0.952 and the average cropping intensity at the regional level was 191%.Bangladesh Rice j. 2017, 21(2): 109-122