Drought stress provokes plants to change their growth pattern and biochemical contents to overcome adverse situations. Soybean was grown under 40 (drought) and 80% (control) of field capacity (FC) to determine the morpho-physiological and biochemical alterations that occur under drought conditions. The experiment was conducted following a randomized complete block design with three replications. The results showed that drought exerted detrimental effects on photosynthetic attributes, leaf production, pigment and water content, plant growth, and dry matter production of soybean. However, drought favored producing a higher amount of proline and malondialdehyde in soybean leaf than in the control. The pod and seed production, grain size, and seed yield of soybean were also adversely affected by the drought, where genotypic variations were conspicuous. Interestingly, the studied morpho-physiological and biochemical parameters of AGS383 were minimally affected by drought. This genotype was capable of maintaining healthier root and shoot growth, greater leaf area, preserving leaf greenness and cell membrane stability, higher photosynthesis, absorbing water and sustaining leaf water potential, and lower amount of proline and malondialdehyde production under drought conditions. The heavier grains of AGS383 make it out yielder under both growth conditions. Considering the changes in morpho-physiological, biochemical, and yield contributing parameters, the genotype AGS383 could be cultivated as a relatively drought-tolerant, high-yielding soybean variety. Further study is needed to uncover the genes responsible for the adaptation of AGS383 to drought-stress environments, and this genotype might be used as parent material in a breeding program to develop a high-yielding, drought-tolerant soybean variety.

A study was conducted to assess the effects of organic amendments on soil aggregates, carbon (C) sequestration, and energy use efficiency (EUE) during five consecutive Boro and Transplanted Aman rice seasons in Bangladesh during 2018–2020. Five treatments (viz., control (only inorganic fertilizers), cow dung (CD), vermicompost (VC), rice straw (RS), and poultry manure (PM)) were used. The organic materials were applied at 2 t C ha⁻¹ season⁻¹ to all the plots, except in the control treatment. Inorganic fertilizers were applied in all treatments in both seasons following integrated nutrient management (INM). The data reveal that PM was found to be more efficient at increasing the water-stable soil aggregates (WSA), followed by the RS, CD, and VC. The WSA in smaller-sized soil aggregates were found to be higher than those in larger-sized soil aggregates. VC was found to be the most effective in terms of C sequestration (29%), followed by PM (26%), CD (22%), and RS (20%). The highest EUE was attributed to the control treatment (9.77), followed by the CD (8.67), VC (8.04), RS (2.10), and PM (1.18), which showed energy wastage in the organic treatments. The system productivity (SP) followed the opposite trend of the EUE. The INM is a better approach to improve the soil health, the C sequestration, and the SP, but it appeared as an energy-inefficient strategy, which suggests that a balanced application of organic and inorganic nutrients is needed in order to achieve yield sustainability and EUE.

Potassium (K) improves the stress tolerance of crop plants, which varies on the timing of K application and crop varieties. Soybean is a promising crop that can easily fit with the cropping pattern during kharif I season, when water logging occurs due to sudden rain. Therefore, an experiment was conducted to determine the effect of K management on the productivity and seed quality of soybean under normal and waterlogged conditions. The treatments comprised three factors, namely soybean genotypes (BU Soybean-1 and BU Soybean-2), waterlogging (WL) (control and WL for 4 days at the flowering stage (FS)), and K application (full dose as basal and 50% as basal +50% as top dress after termination of the flooding). The trial was laid out in a randomized complete block design with three replications. Findings revealed that BU Soybean-1 produced a higher number of pods and seeds pod⁻¹ under control conditions with basal application of K. On the other hand, BU Soybean-2 produced taller plants and heavier grain, improving grain and straw yield under WL conditions when K was top dressed. The varieties absorbed a higher amount of nitrogen, phosphorus, and potassium under control conditions compared to WL when K was top dressed. Similarly, the seed protein content of both varieties was higher in the control condition with a top dressing of K. However, a higher percentage of seed germination was obtained from BU Soybean-2 in the control condition with a top dressing of K. Further, more electrical conductivity and more mean germination time were recorded in the case of BU Soybean-2 under WL with the basal application of K. Split application of 50% of recommended K fertilizer after the recession of flood water could be suggested for improved grain yield in flood-affected soybean growing areas.

Wheat is affected by various biotic and abiotic stresses, especially salinity, which reduces the growth and yield drastically. With this view, an experiment was conducted to observe genotypic differences in agro-morphological, yield, and biochemical responses to salinity. Experimental variables consisted of five salt-tolerant genotypes (G 13, G 20-1, G 9, G 22, G 20-2), one susceptible genotype (G 24) and one standard check variety (BARI ghom 25), which assigned to four levels of salinity with electrical conductivities 0, 4, 8 and 12 dS m⁻¹. Irrespective of genotypes, salinity stress significantly decreased the yield and yield attributes. However, maximum total tillers plant⁻¹, effective tillers plant⁻¹, number of grains spike⁻¹, and grain yield plant⁻¹ was found in salt tolerant genotype G 20-2, followed by genotypes G 13, G 20-1, and the lowest was observed in salt-susceptible genotype G 24. The lowest reduction percentage of yield and yield attributes were also observed in salt tolerant genotype G 20-2 followed by genotypes G 13, G 20-2, and the maximum reduction percentage was found in salt-susceptible genotype G 24. Results showed that the highest amount of proline, glycinebetaine, soluble sugar and soluble protein content were observed in salt-tolerant genotype G 20-2, followed by genotypes G 13, G 20-1, and the minimum was found in salt-susceptible genotype G 24. On the other hand, the lowest hydrogen peroxide (H₂O₂) and melondealdehyde (MDA) accumulation was detected in the same salt-tolerant genotype G 20-2, followed by G 13, G 20-1, and the maximum was observed in salt-susceptible genotype G 24. Therefore, higher accumulations of compatible solute in the tolerant genotypes reduce the oxidative stress, and provide the higher yield.

Soybean genotypes G00006, BD2336, AGS383, PK472, BCS1, NCS1, BU Soybean1 and BARI Soybean6 were evaluated under 20% (drought) and 80% (control) of field capacity based on morpho-physiological and yield response to drought. The results revealed that plant height, leaf number, chlorophyll content, photosynthesis, stomatal conductance, transpiration rate, relative water content and water uptake capacity of soybean drastically reduced due to drought. However, root: shoot ratio increased under drought condition. Across the genotypes, the root : shoot ratio ranged from 0.20 to 0.47 in control, while 0.22 to 59 in drought condition. Genotypes BD2336, AGS383 and G00006 produced higher number of pods and seeds, whereas minimum yield reduction was recorded in AGS383 under drought. Based on drought tolerance index, AGS383 ranked 1st, while BD2336 and PK472 ranked 2nd and 3rd position, respectively. High grain yielding ability of AGS383 suggested that it could be cultivated in drought prone environment. J. Bangladesh Acad. Sci. 47(2); 223-240: December 2023

A field trial was laid out to mitigate the detrimental consequences of waterlogging (WL) on morpho-physiology and productivity of soybeans through potassium (K) application. Soybean genotypes AGS383 and G00166 were tested against 4 days of WL at the flowering stage. The K fertilizer was applied as (i) basal (full dose) and (ii) basal (50%) + top dress (50%) after the termination of a flood. The experiment's results showed that the WL negatively affected leaf greenness, water and chlorophyll (Chl) content, plant height, nodule and pod production, and soybean seed yield. However, the split application of K fertilizer minimized the detrimental effect of WL in the case of AGS383. This genotype produced taller plants, contained more Chl and water, higher nodules, bold seeds, and accumulated higher amounts of mineral nutrients in their grains under WL condition with K as basal + top dress after the termination of a flood. J. Bangladesh Acad. Sci. 47(2); 155-167: December 2023