Due to climate change, Bangladesh has been rated as the third most vulnerable country in the world in terms of number of people affected with respect to sea level rise. The entire coastal region of Bangladesh is affected with floods, water-logging, surges, droughts and salinity intrusion while salinity has been engulfing new areas in the region gradually.Thus, climate risks to agricultural production are expected to increase in coming decades.
Two to three decades ago, farmers used to cultivate boro rice and other winter crops like pulses, wheat, vegetables, etc. in coastal area in the dry season and received good yield and income. But nowadays, farmers left boro rice and other winter crops cultivation in dry season due to increased salinity as well as severe scarce of salt-free irrigation water. As a result, thousand hectares of land which is almost half of the total cultivable land in coastal area now remain fallow in the dry season.
More than one third farm households in the coastal area are now cultivating only one crop in a calendar year, i.e. aman rice during monsoon while most of the cultivable land remains almost barren in the dry season. As a result, cropping intensity in coastal area is minimum compared to national average. In coastal area, a large number of households are suffering from malnutrition while it retards child growth. Most of the households in this area not having balance diet remain undernourished and become easily susceptible to diseases. Malnutrition among women of reproductive age increases the risk of mortality during labour and delivery and puts their newborn kids at risk of long-term deficiencies.
Pulses crops likes lentil, mungbean, grass pea, cowpea, etc. are the traditional pulse crops of Bangladesh and were grown well in Bangladesh including coastal belt. Pulses having high nutritive value are consumed mainly as dal along with rice as one of the most popular dish called dal-bhat. These crops remain staple food-stuffs to this day but their production in coastal area is declining due to untimely as well as unexpected rainfall in dry season, water-logging situation in coastal-belt as well as increased salinity in the south due to climate change. Pulses in Bangladesh are the only source of nutrition in the family diet of poor households. Thus, production of pulses would be good means to improve household food and nutrition security. Pulses are suitable for standing cropping process as it needs less time or less term, less input and aridity tolerant quality. To alleviate human malnutrition for the poorest segment of the country’s population, pulses have been identified as crops with excellent potential.
Thus, climate-smart technology of pulses production should be developed. Salt-tolerant or water-logged tolerant or multiple stress tolerant variety of pulses crops should be developed for dry season which may introduce in aman (monsoon) rice-based cropping system at coastal Bangladesh. The main biophysical impediments to increasing pulses cultivation in Bangladesh relate to late harvest of aman rice. Generally, farmers go for winter crops like pulses cultivation after harvesting of aman rice. The proper time to cultivate most of pulses crops is in November. But due to presence of aman rice crops in most of the lands in November, farmers have no scope to avail the right time to cultivate such winter crops. This delayed cultivation hampers the normal yield and also increase the production cost of different winter crops. It is mentionable that when farm households will be able to cultivate winter crops like pulses in right time (i.e. in November), farmers will get more yield for timely cultivation and may able to minimise the production cost by reducing pesticides, fertilisers, inter-cultural operations while farm households will get good price of their products for early marketing.
The recent advent of early maturing rice varieties has increased significant scope for timelier planting of winter (rabi) crops and successful capture of residual soil moisture. Through a PhD research by the author as well as demonstration trials in farmers’ field, it is proved that recently developed high yielding short duration aman rice variety developed by Bangladesh Rice Research Institute (BRRI) is unique to fits well as short duration aman rice-pulses within intensive cropping system. The recent developed short duration rice variety’s life cycle is 110-120 days with field duration only 90-100 days, through which, it is now possible to harvest rice in the month of October instead of late November and December while farmers will be able to cultivate winter crops like pulses in residual soil moisture in right time, i.e. in late October to November.
Besides, soil health is also decreasing day by day, as organic matter is now available below one percent at soil level which is supposed to be available at least five percent for better production. Introduction of pulses is not only ensuring as an additional harvest and human nutrition, but also improve soil nutrient status by nodule formation at root level and add organic matter when decomposing pulses, especially mungbean plants into the soil, just immediate after harvesting of mungbean pods from plants. On completion of an extensive action research, it is now claimed that growing short duration mungbean in short duration aman rice – winter (rabi) crops – fallow cropping pattern offers a great promise to avert food insecurity and improve nutrition both human and soil in the southern districts of Bangladesh. More than 60 per cent cropped area in the southern region is medium land representing favourable environment for mungbean cultivation, where mungbean can be fitted immediately after rabi crops harvest.
A research conducted by the author on the effect of variety and planting time of mungbean, where it was found that sowing time influenced significantly on the yield performance of mungbean. Planting of mungbean in February and even early March produced the highest yield compared to planting later. Mungbean should not be planted in late March as it produced very low yield due to excessive rainfall during flowering stage. Thus, mungbean can be planted in February which to be harvested by May. After mungbean harvest, farm households can transplant high yielding short duration aman rice timely that matures at the end of October while farmers can cultivate winter (rabi) crops in November easily.
On the other hand, multiple cropping in terms of mixed cropping, relay cropping, inter-cropping having important opportunities to meet diversified family need of various crops as well to increase production per unit land area. Winter (rabi) season is particularly favourable for growing non-rice field crops in Bangladesh. Farmers in coastal area traditionally practicing relay cropping of grasspea in aman rice fields while farmers are seeding the grasspea seeds in aman rice fields during flowering/fruiting stage of aman rice. Now-a-days, farmers are not getting much benefit from this practice due to uneven and untimely rainfall. This year is a big example where most of the coastal farm households lost their grasspea due to unexpected rainfall in December.
The concept of mixed cropping is to grow two or more crops together on the same piece of land in a given season while the sowing time of the crops will be the same and harvesting time is also approximately similar. Traditionally, it is used by subsistence farmers primarily to increase the diversity of their products and to stabilise their annual output. Farmers of Bangladesh have been practising mixed cropping from time immemorial. According to many investigators opinion, mixed cropping provides better control of weeds, insects and diseases. A proper association of a pulse and a cereal crop might be a balanced diet for the subsistence farmer. Lentil is an important pulse crop containing 23.7 per cent protein while wheat is a tall erect stature, whose limited population will not drastically cut off solar radiation to the shorter bushy crop such as lentil. Mixed cropping of wheat and gram produced higher yield than any one of the crop individually. According to research findings conducted by the author, the combined grain yield of full seed rate of lentil (i.e. 40 kg/ha) along with 35 percent seed rate (i.e. 42 kg/ha) of wheat produced significantly higher yields over mono-cropping, where lentil was considered as the main crop and wheat was considered as the subordinate crop. Mixing of 35 per cent seed rate of wheat with full seed rate of lentil under one or two light irrigations could produce approximately 65 per cent additional yield over pure culture of lentil. In addition, preservation of fresh water in pond and canal in coastal area during monsoon is a useful way to cultivate winter crops in dry season while such crops only to be selected which requires very minimum water and having short duration nature.
Considering the above circumstances, pulse production should be increased rapidly to improve the national nutritional status. At present, the country’s demand is close to two million tons of pulses while the country produces only 0.53 million tons. Therefore, researchers, policy makers, and farmers should give proper attention to develop technology and good variety of pulses in adverse weather to meet the increasing demand of pulse that improves both food and nutrition security in Bangladesh.
To overcome this adverse situation in coastal area due to changed climate as well as to improve livelihoods of vulnerable poor farm families in a sustainable way, the University of Western Australia under joint collaboration of Bangladesh Agricultural Research Institute and Bangladesh Agricultural University along with Australian Institute as Commonwealth Scientific Industrial Research Organization (CSIRO) comes forward to implement a project on ‘Incorporating salt tolerant wheat and pulses into smallholder farming systems in southern Bangladesh’ under financial support of Australian Centre of International Agricultural Research (ACIAR) and Krishi Gobeshona Foundation (KGF).
The aim of the project is to improve smallholder incomes in southern Bangladesh through improved productivity and profitability of dry-season cropping on non-saline land with pulses as well as with improved salinity tolerance wheat on saline land. The best technology in farming is the one which the farmers and beneficiaries use enthusiastically for their gain. This ACIAR-KGF project is scheduled to continue until the end of the 2020. By then, it is hoped that improved cultivation technologies as an output of the project would have been widely demonstrated across the southern Bangladesh and many farmers of coastal area would have adopted the technology and enjoy the benefit as outcomes of the project.
The writer is the Deputy Project Leader of University of Western Australia