The conception of critical limit (CL) of a nutrient element distinguishes its deficiency from sufficiency, which could advise fertilizer application. A pot culture experiment was conducted during Rabi season (2019–2020) to study the CL of sulphur (S) in soil and plant. A total of 20 soil samples collected from intensive cropping areas of three agroecological zones (AEZs) of Bangladesh were used in the experiment. The 0.15% CaCl2 extractable S (expressed as available S) contents of the test soils ranged from 6.84 mg/kg to 38 mg/kg. Wheat (Triticum aestivum L.) cv. BARI gom 30 and mustard (Brassica napus L.) cv. BINA sorisha 9 were used as test crops in this study. There were two rates of S application to soil-0 and 15 mg/kg for wheat and 0 and 18 mg/kg for mustard from gypsum (CaSO4.2H2O). Each S treatment was replicated thrice. Dry matter yield, S content and S uptake by the crops increased with added S. For mustard, the CL of soil S was estimated to be 14 mg/kg by graphical procedure and 11 mg/kg in statistical method while plant tissue concentration showed the CL of 0.35% in both methods. The CL of soil S for wheat was found to be 14 mg/kg and 11 mg/kg in graphical and statistical methods, respectively, and the CL of plant tissue concentration was recorded as 0.14%, in both methods. It is expected that mustard and wheat crops would respond to S fertilization in soils containing S at or below the CL. The results would be useful for predicting crop (wheat and mustard) response to S fertilizer and developing efficient S fertilizer management to promote sustainable crop production.

The food items, such as pulses and oil crops, are influential means of nutritional security for the people in Bangladesh. Pulses are widely called here as an alternative to meat for poor households. The study aimed to predict productivity and national demand of pulses and oil crops in Bangladesh by 2030 and 2050, minimizing the supply and demand gaps of these crops. Using the ARIMA model developed by Box and Jenkins, the current study projected Bangladesh’s pulse and oil crop demand and supply for the years 2030 and 2050. The projections showed that the total demand for pulses in 2030 will be 17.9 lakh MT and further increased to 19.5 lakh MT in 2050. The deficit in the supply of pulses will be 12.36 lakh MT in 2030 and 9.26 lakh MT in 2050 although the shortage of pulses will disappear as a result of productivity improvements and innovations. Per capita consumption of edible oil in Bangladesh is 20–22 g per day. The majority of domestically produced soybean (5% of total demand) is used in the feed industries, while edible oil from soybean depends on import. The supply of mustard oil is predicted to be in deficit by 0.30 lakh MT in 2030 and 1.68 lakh MT in 2050. Nevertheless, the estimates also warn that supply of these food items could be threatened due to climate changes. In facing future challenges, supportive government policy and substantial investment in research and extension should be given priority for technological innovation and productivity improvement. Government also needs to develop a strategic import substitution policy for higher production of these crop and storage facilities.