Historically, or the 2nd century BC. According to Boyce

Historically, Bengal was known as Sonar Bangla, meaning ‘Golden Bengal’ since rich alluvial soil, warm-round temperatures, and plentiful surface and surface water resources by three mighty rivers the Ganges, Brahmaputra, and Meghna and their countless tributaries give this region mammoth agricultural potential. That is why agriculture is the major source of livelihood of the Lions’ portion of the populace of the territories that comprised the Bengal provinces as in 1911, and afterward divided independent Bangladesh and West Bengal. The huge number of the population those directly in agricultural processes in the territories that constitute Bangladesh today. During the period of British rule about fourth-fifth (77.3%) of the people was dependent on agriculture and belonged to a diverse social groups; zamindars, tenant-cultivators, bargadars and agricultural laborers, and crop production throughout the ancient, medieval and the British periods remained the dominant sub-sector which was the most fundamental character of the agrarian economy. The crop included paddy, jute, wheat, jowar, barley, sugarcane, tobacco, oilseeds, potato, onion, garlic, opium, indigo, tea and various types of vegetables, pulses, spices and condiments where rice was the most significant and oldest crop. The other three sub-sector of agriculture i.e., livestock, fisheries, and forestry were relatively trivial. Needless to say which mold remains the similar today. The initial allusion to this crop is found in the Mahasthan Brahmi Inscription belonging to the 3rd or the 2nd century BC.  According to Boyce (1987), the plight of the rural poor in Bangladesh is in part a legacy of colonial rule. In addition to that the poor majority of Bengal –whose ancestors witnessed the destruction of great handloom textile industry, the imposition of an oppressive landlord system, and the systematic neglect of irrigation, drainage, and flood control- have yet to reap the promised rewards for their past sacrifices. Although the government has professed to give top priority to agricultural production and attainment of food self-sufficiency, no radical change in policies can be observed after the emergence of Bangladesh. In Bangladesh agricultural is, still somehow, ‘gamble in the monsoon’ which indicates that production was affected sometimes by excessive rainfall and sometimes by drought. Some crop is very important (also vegetable) in context of Bangladesh agriculture due to peoples’ habit to produce and consume it. In agro-ecological context, it even plays a more significant role in diverse way less irrigation is one of them. The north-west region of Bangladesh is in a vulnerable situation in the context of availability of irrigation water owing to climate change. These are the pushing factors that pull them to change the cropping pattern in this region which will revive the fertility of the land and produce maximum alternative carbohydrate for human lives as well as profits.