An attempt was made to investigate appropriate two-stage drying techniques for quality of paddy seeds. In this research, two options of two-stage drying were conducted for three varieties of paddy and Guti Swarna). In both options, first stage drying was carried out by a fluidized bed dryer using three temperatures (50, 55, and 60 C) at constant bed thickness of 15 cm. After tempered, in the first option, samples were further dried in second stage by sun drying (28-32 C).In the second option, samples were further dried in second stage in same fluidized bed dryer using three temperatures (35, 40, and 45 C). Comparison of germination percentage in the first option, it revealed that higher germination percentage was obtained than sun-drying method while dried at 50 C in the first stage followed by sun-drying method at 30 ± 2 C in the second stage except in case of Guti Swarna. In the second option, it revealed that higher germination percentage was obtained than sun-drying method while dried in fluidized bed dryer at 50 C in the first stage followed by 35 C in second stage except in case of variety Guti Swarna. Therefore, drying at optimum air temperature for both options can be applied for paddy seed drying in Bangladesh. Practical ApplicationRice (Oryza sativa) is one of the most important food crops in all over the world.According to the Bangladesh Bureau of Statistics (Yearbook of Agriculture Statistics, 2018) about 3.6 million tons of paddy produced in Bangladesh. The most important input for any agricultural production is seed than other inputs. In Bangladesh used only 15% of the total paddy seed is quality seed. Drying is an energy-intensive and most important postharvest operation for the production of quality seed. The outcomes of the proposed research can play an important role in the improvement of the socioeconomic status of paddy seed growers and product processors of Bangladesh. It will be helpful for seed company who produces a huge amount of seed and also helpful in the rainy season when sun drying is not available. | INTRODUCTIONAs 80% population around the world eats rice (Oryza sativa), it is one of the most important food crops. Rice is the staple food of about 165 million people in Bangladesh. According to the Bangladesh Bureau of Statistics (Yearbook of Agriculture Statistics, ), about 3.6 million tons of paddy produced in Bangladesh. It provides nearly 48th of rural employment, regarding two-thirds of total calorie provide and regarding a common fraction of the whole macromolecule intake of a median person within the country. For this reason, farmers in

In the present world, climate change is a mass talked issue. Because of climate change, humans and animals are under the risk of threatening. The scientist has pointed out that main reasons for climate change are waste. Waste is generated from household chores and industries, factories etc. that are affecting the balance of the environment in many ways. This waste may be of various types such as solid, liquid, gaseous etc. Therefore, the study was taken to assess the chemical components contain in wastewater in Dinajpur Sadar, Bangladesh. This study was aimed to evaluate the chemical compositions of the generated wastewater including comparison with the groundwater. The data concerning to the rice mill waste water in Dinajpur, Bangladesh was obtained from individual field visits by interviewing with owner and worker in the rice mills. The wastewater samples were collected randomly from different rice mills. A laboratory experiment was performed to determine the chemical constituents of the wastewater sample. The wastewater contained of pH(6.11-6.18), EC(181.47-185.23 µScm-1), Na(26.19-28.89 mgl-1), Ca(45.41-51.26 mgl-1), Mg(47.12-49.8 mgl-10), K(184.7-191.3 mgl-1), TDS(45.94-47.96 mgl-1), HT(306.7-332.33 mgl-1), S(11.05-13.25 mgl-1), Cl-(522.45-526.182 mgl-1), HCO3-(5.12-6.99 mgl-1), DO(0.46-0.53 mgl-1), P(17.01-21.54 mgl-1). The obtained concentration of Ca, EC, pH, Na and HCO3- were within the reported range of groundwater in Dinajpur, Bangladesh. The concentration of Cl-, K, P, Mg and hardness in the wastewater were above the concentration of reported groundwater in Dinajpur, Bangladesh. On the other hand, the concentration of TDS in the wastewater was less than the reported concentration of groundwater in Dinajpur, Bangladesh.

A research was carried out to assess the suitability of surface water for irrigation purposes. For this reason, 56 samples of surface water were collected from each union of Dinajpur sadar upazilla, Dinajpur. The analysis was included pH, EC, TDS, Ca, Mg, S, P, Na, K, Cl- and HCO3- to evaluate the suitability of surface water for irrigation purposes. Almost all the water samples were within the recommended pH value for irrigation and a great impact on crop production. With respect to electrical conductivity (EC) samples were low to medium salinity. For total dissolved solids (TDS), all samples were considered as freshwater for irrigation. On the basis of Ca, Mg, S, P, Na, K, Cl- and HCO3- all samples could safely be used for irrigation and would not affect the soils.

An attempt was conducted taking three wheat varieties (BARI gom-24, Shatabdi, Bijoy) to investigate the application and suitability of single-stage fluidized bed drying for quality wheat seeds in terms of germination percentage. Drying of wheat seed was conducted in a fluidized bed dryer at three temperatures of 35°C, 40°C, and 45°C at a constant bed thickness of 13 cm and 4.5 m/s of air velocity. Total drying time required for drying of each variety 210 min (3.5hr), 150 min (2.5hr) and 80 min (1.3hr) at temperature 35°C, 40°C, and 45°C respectively for reduction of moisture from 16.98±0.15% to 12±0.1% wb. In contrast, sun drying (33±2°C) took 270 min (4.5 hr). It was shown, the drying time required in the fluidized bed drying method was almost 22-71% shorter than the sun drying method. The germination percentage was 94.67%, 97.33%, 88% for the variety “BARI gom-24” 93.67%, 97%, and 91.33% for the variety Shatabdi and 95%, 96.67%, 89.67% for the variety Bijoy while dried in a fluidized bed dryer at temperature 35°C, 40°C, and 45°C respectively. The germination percentage of sun-dried samples was 90.67% (BARI gom-24), 92.33%. (Shatabdi) and 92% (Bijoy). In the comparison of germination, wheat seed samples dried in the fluidized bed dryer at 35°C, 40°C showed a higher germination percentage than sun drying wheat seed samples. Therefore, the proposed drying technique does not only facilitate faster removal of moisture content, and also a higher germination percentage was found than the existing sun drying method. So, fluidized bed drying can be effective for wheat seeds in Bangladesh.