Purpose Information on carbon dioxide (CO 2 ) emission from different organic sources and their temperature sensitivity to decomposition is scarce in Bangladesh. Therefore, this study quantified the rates of CO 2 emission and carbon (C) degradation constants from different organic material mixed soils at variable temperatures in two laboratory experiments. Methods The first experiment was conducted at room temperature for 26 weeks to study CO 2 emission and C mineralization using vermicompost, chicken manure, cow dung, rice straw, and rice husk biochar. Weekly CO 2 emission was measured by alkali absorption followed by acid titration. The second experiment comprised two factors, viz. four organic materials (vermicompost, chicken manure, cow dung, and rice straw) and six temperature regimes (25, 30, 35, 40, 45, and 50°C). Organic materials at 2.5 g C kg -1 soil were mixed in both experiments. Results CO 2 emission reached the peak at 5th weeks of incubation and then decreased with irregular fashion until 21st week. The C emission loss followed in the order of chicken manure [ rice straw [ vermicompost [ cow dung [ rice husk biochar, and C degradation constants indicated the slower decomposition of rice husk biochar compared to cow dung, vermicompost, chicken manure, and rice straw. Temperature positively enhanced the mineralization of organic materials in the order of 50 [ 45 [ 40 [ 35 [ 30 [ 25°C, which contributed to higher availability of soil phosphorus. Conclusions High temperature increased mineralization of tested organic materials. Because of slower decomposition rice husk biochar, cow dung and vermicompost application can be considered as climate-smart soil management practices that might help in reducing CO 2 emission from soil.

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An experiment was conducted in a 19-years old aonla orchard from October 2019 to January 2020 at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) research farm to determine the performance of different radish varieties in aonla based multistoried agroforestry systems. The study consisted of two factors viz. four agroforestry systems (aonla + carambola, aonla + lemon, aonla only, and open field) and four radish varieties (BU mula-1, BARI Mula-1, BARI Mula-2 and Rocky 45) laid out in a two factorial randomized complete block design with three replications. Findings exhibited that light availability in the open field was 727.02 µmol m-2s-1 which was significantly higher over the aonla based multistoried agroforestry systems. Light received by the aonla + lemon, aonla, and aonla + carambola systems were 74.13, 65.57, and 52.77% of the open field, respectively. The highest (276.47 g) leaf fresh weight produced by Rocky 45 was noticed in aonla + carambola system and the lowest leaf weight produced by BU mula-1 was found in an open field. The highest root fresh weight (592 g) was produced by Rocky 45 in the open field, and the lowest root fresh weight (102.60 g) was produced by BU mula-1 in aonla + carambola based system. The highest root yield (39.47 t/ha) of Rocky 45 was produced in an open field and a higher leaf yield (18.43 t/ha) was reported in BU mula-1 among four radish varieties. Among four radish varieties, Rocky 45 performed better yield in open field conditions and aonla based agroforestry system.

Fruit tree vegetable-based agroforestry systems (FVAS) are being introduced in highland cropping systems of Bangladesh. This combined production system is applicable against changing climate, ensuring nutritional requirements along with food security, ecological balance, and economic profitability. The present study explored the performance of cauliflower as lower story crop in aonla based multistoried agroforestry system. The experiment was laid out in randomized complete block design (RCBD) with four replication. The treatments were T1= Aonla + carambola + lemon + dragon fruit + cauliflower, T2= Aonla + dragon fruit + cauliflower, T3= Dragon fruit + cauliflower, T4= Cauliflower in the open field (Control). Among different combinations of agroforestry systems, the highest curd yield of cauliflower (15 t ha-1) was recorded under dragon fruit-based system (T3) whereas most of the morphological parameters were maximum in the aonla + carambola + lemon + dragon fruit-based system (T1). The highest benefit–cost ratio (2.95) was noted in aonla+dragon+cauliflower-based system (T2) followed by dragon fruit based system (T3), while the highest land equivalent ratio (3.78) was calculated in the aonla + carambola + lemon + dragon fruit-based system (T1). This study revealed that, aonla + dragon + cauliflower based agroforestry system showed relatively higher economic returns and maximum land use efficiency in the upland cropping system.