A shift in agricultural management from chemical to organic practices is expected to reduce environmental hazards and improve soil health and productivity in Bangladesh. To increase knowledge of the impact of probiotic cultures and organic farming practices on the physical and chemical properties of Bangladeshi soils, an investigation was carried out during the period from July 2016 to June 2019. The study included nine treatments using combinations of probiotic cultures and organic farming practices. The experiment used a randomized complete block design with three replicates. The probiotic cultures and organic practices increased soil moisture content, porosity and silt particle and decreased bulk density, particle density and sand particles. The organic matter content (11.66%), nutrient availability and electrical conductivity (8.96%) increased with the organic practices, while pH of the soil decreased. The largest significant change in the physical properties (p ≤ 0.05) was in the compost + vermicompost + green manuring treatment, while for chemical properties this was in the poultry manure + vermicompost + green manuring. These findings suggest that the above combinations of organic treatments provide most benefit to the soils of the practices considered.

Achieving high-yielding crops while also improving nitrogen use efficiency is a significant challenge for agricultural production in Bangladesh. We investigated the impacts of applying nitrogen (N) using different management options in wetland rice on a calcareous dark gray soil over three seasons. These included (1) the recommended dose of available N as prilled urea, (2) the recommended N dose plus 25% extra of available N as prilled urea, (3) 25% less than the recommended dose of available N as prilled urea, (4) the recommended dose of prilled urea in 2 t ha⁻¹ cow dung, (5) the recommended dose as urea super granules (USGs) by deep placement, (6) 4 t ha⁻¹ biochar with the recommended dose of prilled urea, and (7) Zero N. It was found that the growth, yield, and N use efficiency (NUE) were significantly different from the results obtained for prilled urea in all the alternative fertilizer options. The deep placement of USG consistently increased plant height, total number of tillers per plant, effective tillers per plant, chlorophyll content, panicle length, grains per panicle, and 1000-grain weight. The yield increases over recommended prilled urea were 5.22% for USG followed by biochar with the recommended dose. Similarly, using the deep placement of USG gave the highest yield and harvest index. In addition, compared to the recommended dose of prilled urea, the deep placement of USG increased NUE by 13%, agronomic N efficiency by 20%, and recovery N use efficiency by 19%. This suggests the rate of N application could be reduced by up to 8% without impacting yield by using deep placement of USG instead of prilled urea. The cost–benefit ratio was higher for the deep placement of USG than all other treatments. Biochar with the recommended dose of prilled urea also showed good results in terms of growth, yield, and NUE (41.8, 43.0, and 41.7, respectively, during three sequential years), but the extra cost of the biochar reduced the cost–benefit ratio. These findings suggest that the deep placement of USG is the best option for improving the yield of rice while also improving N use efficiency.

In Bangladesh, a large quantity of mango is lost every year due to post-harvest diseases, particularly anthracnose and stem-end rot. Therefore, sustainable post-harvest management is crucial for reducing the losses. In this study, we investigated the effects of plasma treatments on mango to mitigate post-harvest losses. The mangoes were submerged in distilled water (DW), and then DW-submerged mangos were treated for 10 minutes employing multi-capillary bubble discharged plasma jet system using air and oxygen gases separately. Plasma treatments significantly influenced disease incidence, severity, and physio-chemical properties of mangoes. On the 10 ^th day, the Khirsapat mango, treated with a 10-minute air-discharge plasma, exhibited a significant (≤0.05) reduction in anthracnose incidence (20%) and severity (2.33%) compared with control (incidence 80% and severity 61.67%). Similarly, the 10-minute air-discharge plasma treatment consistently reduced the incidence (20%) and severity (15%) of stem-end rot. For the Fazlee variety, the incidence (22%) and severity (3.67%) of anthracnose were reduced compared with the control (89% and 56.67%), while stem-end rot was completely inhibited for up to 10 days under the 10-minute air-plasma treatment. In addition, both mango varieties showed increased total soluble solid (18% and 19%), retained good moisture content (77.82% and 85.34%), but reduced physiological weight loss (3.12% and 8.36%), and extended shelf life (6 days). Firmness degradation was lowest in air plasma treatment (4.20% in Khirsapat and 4% in Fazlee) compared to control (5.76% and 5.79%). It is interesting to note that the plasma treatment of both varieties showed higher mineral contents (K, Ca, Mg, and P), while Vit C declined modestly (16.0 and 25.10 mg/100g) compared to control. Therefore, a 10-minute air-discharge plasma treatment effectively reduced disease incidence and severity through enhancing TSS, mineral contents, physiological properties, and overall storage life that highlighting its potentiality as an eco-friendly postharvest technology.

To understand potential sources and losses of nitrogen from farming systems in Darusa, Bangladesh, a detailed survey of farming practices was conducted. A total of 100 households were randomly selected using demographic and agricultural information about the farmers in the study area. Data were used to stratify the farmers according to their operational land holding, livestock numbers (tropical livestock unit), use of irrigation, age, and educational level. Four clusters of farm households were identified, and nine households were randomly selected from each cluster for a total of 36 households. These 36 households completed more detailed surveys about their cropping and livestock. The surveys identified local practices of nitrogen management in different crops and types of livestock. Further information on traditional practices for soil fertility management was obtained by interviewing selected farmers. The results show that the major use for organic residues from crops and livestock is to provide fuel. Crop residues were used as fuel by 84% of farmers, with 23% using all of their crop residues as fuel. Some manure was used as fuel by all farmers, with 56% of farmers using most of their manure as fuel. As a result, 23% used no crop residues and 56% used less than half of their manure to improve soil fertility. This suggests that recycling of nitrogen in the study area is low. Soil analysis indicates that the organic matter and nitrogen contents of the soil in the study area were only 1.43% and 0.08%, respectively. Therefore, further recycling of organic residues should be practiced in order to reduce losses of available nitrogen from the system. More research is needed to quantify nitrogen lost by these practices and to draw up a full nitrogen budget for the study area.

Organic matter plays an important role in the health and productivity of soils, but its depletion is a common problem in households in low-income countries. This is due to lack of and competing uses for organic resources, and limited information on recycling methods. Therefore, here we review low-cost and labour-efficient innovations to improve recycling of organic wastes, stabilising residues so that soil organic matter can be increased with less inputs and enhancing nutrient content to produce a more effective organic fertiliser. Composting, anaerobic digestion and pyrolysis are all processes that stabilise organic matter. Innovations in treatments are needed to improve stabilization and control the release of nutrients so that they are available to crops in the right amounts and at the right time. This can be achieved by maintaining appropriate treatment conditions: for composting, carbon to nitrogen ratio 25–35, carbon to phosphorus ratio ∼50, pH 5.5–8.5 and 50%–60% moisture content; for anaerobic digestion, carbon to nitrogen ratio 20–35, bulk density 0.6–0.8 g cm ⁻³ , lignin content < 7.5%, pH 6.8–7.4 and moisture content 85%–95%; and for pyrolysis, carbon to nitrogen > 40 and moisture content < 20%. Different methods to achieve these ideal conditions are discussed, including appropriate choice of treatment method, co-composting/co-digestion for ideal nutrient content, enhancing nutrients using collected urine, nitrogen-fixing plants, bioslurry or by inoculating with bacterial communities, absorbing excess nutrients on biochar, adjusting pH using wood ash or biochar, pre-treatment to break down lignin and cellulose, and designs to achieve ideal moisture and temperature. Innovations should also ensure that treatment processes do not overuse or compete with other important household resources, such as finances, water or labour. We draw together findings to identify methods with most potential to improve soils in low-income countries, providing decision tables to guide selection of approaches for different contexts.

Rice blast disease, caused by Magnaporthe oryzae, is a major threat to global rice production. Eco-friendly biocontrol agents offer a sustainable alternative to chemical fungicides for managing this disease. This study evaluated 8 biocontrol agents for rice blast management and plant growth promotion under controlled conditions. The antagonistic activity of selected biocontrol agents against M. oryzae was assessed through in vitro assays, followed by in vivo evaluation of disease incidence and severity, plant physiological traits, biomass accumulation, and yield components across 3 consecutive cropping seasons. Among the tested agents, Pseudomonas aeruginosa (SB3) exhibited the strongest antagonistic activity, inhibiting the mycelial growth of M. oryzae by 94.24% in vitro. Consistently, it significantly (p ≤ 0.05) reduced disease incidence (6.67%) and severity (1.11%) under greenhouse conditions, whereas the control treatment showed 20% disease incidence and 4.17% disease severity. Furthermore, application of P. aeruginosa (SB3) significantly enhanced plant growth traits and leaf chlorophyll content, and had a remarkable positive effect on yield contributing characters and rice grain yield (increased by 27.37% over the control). Bacillus velezensis (RB4) also produced favorable results across most evaluated parameters; however, its effects were comparably lower than those of SB3. Overall, this study provides evidence that P. aeruginosa (SB3) is a promising biocontrol candidate that can enhance rice yield, supporting its potential application in sustainable and eco-friendly rice production.