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.

Climate change is making droughts more frequent, which is a major problem for crop yield, especially for crops that are vulnerable to drought, such as common buckwheat (Fagopyrum esculentum). Drought stress affects negatively on physiological and biochemical processes of plants, leading to reduced yields. This study addresses the knowledge gap regarding effective strategies to mitigate drought-induced damage and enhance productivity in buckwheat. We hypothesized that iron oxide nanoparticles (Fe₃O₄ NPs) and rice husk biochar could improve drought tolerance in buckwheat by modulating its physiological and biochemical responses. To test this, buckwheat plants were grown under well-watered (80% of field capacity, FC) and drought (40% of FC) conditions following a completely randomized design (CRD) with three replications. Results showed that the application of 50 g/kg rice husk biochar and 400 ppm Fe₃O₄ NPs, either separately or in combination, significantly enhanced the yield and improved key physiological and biochemical traits, including relative water content, photosynthetic rate, stomatal conductance, chlorophyll content, and antioxidant activity. The combination of Fe₃O₄ NPs and rice husk biochar led to improvements the plants’ relative water content, photosynthetic rate, chlorophyll levels, membrane stability index, proline, antioxidant activity (DPPH), and seed yield by 22.37, 17.11, 43.05, 16.07, 43.75, 8.59, and 50.87%, respectively compared to untreated drought plants. Moreover, this treatment reduced oxidative stress indicators such as hydrogen peroxide and malondialdehyde by 31.09 and 38.19%, respectively. These results show that Fe₃O₄ NPs, when combined with rice husk biochar, significantly improve drought tolerance in common buckwheat, providing a viable strategy to increase crop yields in water-limited environments. In view of climate change, this study emphasises the potential of combining biochar with nanomaterials for sustainable agricultural practices.

Salinity stress severely limits soybean (Glycine max L.) productivity by disrupting physiological and biochemical processes. This study investigated the potential of magnesium oxide nanoparticles (MgO-NPs) to mitigate salt-induced damage. Soybean plants were grown under two salinity levels-non-saline (0 mM NaCl) and saline (75 mM NaCl)- in a controlled pot experiment. At the trifoliate stage, leaves were sprayed with MgO-NPs at 0, 100, 200, 400, and 600 ppm. Salinity markedly reduced relative water content (RWC) (to 69%), photosynthetic rate (to 20 µmol CO₂ m^-2 s^-1), and membrane stability index (MSI) (to 56%), while increasing oxidative stress markers. Foliar application of 400 ppm MgO-NPs significantly alleviated these effects, increasing RWC to 87%, photosynthesis to 35 µmol CO₂ m^-2 s^-1, and MSI to 78%. Treated plants showed higher chlorophyll and carotenoid contents, along with elevated proline and soluble sugars and reduced malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) levels. Antioxidant activity improved modestly under both saline and non-saline conditions. Importantly, 400 ppm MgO-NPs enhanced yield traits under salinity, increasing pod number, 100-seed weight, and seed yield per plant by about 30%-38%. These results indicate that MgO-NPs, particularly at 400 ppm, effectively mitigate salinity stress by modulating physiological and biochemical mechanisms, with strong potential for improving soybean performance under saline environments. Field studies are suggested to validate practical application.

Ninety seven maize (Zea mays) genotypes were evaluated for germination and early seedling characters under PEG6000 (8%) induced drought stress to identify drought tolerant genotypes. Descriptive statistics for percentage of seed germination and abnormal seedling, shoot length, root length, and shoot dry weight, root dry weight, seedling length, seedling dry weight, and vigor index revealed significant variation among the genotypes studied. The percentage of germination and abnormal seedlings varied greatly among the genotypes. The first and second principal components (PC) of PCA results accounted for 73.15 and 26.85% of the total variation of maize genotypes, respectively. The first PC variation consisted primarily of relative seedling shoot dry weight and relative seedling root dry weight. Cluster analysis grouped the genotypes into four clusters. Cluster III genotypes performed better in terms of relative shoot dry weight, relative root dry weight, and number of abnormal seedlings, indicating drought tolerance. Very poorly performance was shown by genotypes in cluster IV, whereas moderately performance was shown by genotypes in cluster II and I. The clusters differed significantly from one another, according to D2 and multivariate analysis. Thirty six genotypes viz. BD-814, BD-810, BD-812, BD-821, BD-815, BD-10015, BD-10238, CML-552, BD-822, BD-826, CML-341, CML-555, CML-591, CML-523, CML-564, BD-817, BD-10018, BD-10240, CML-577, CML-342, CML-556, BD-837, CML-544, BD-827, BD-806, BD-835, BD-840, BD-842, BD-10010, CML-562, BD-10239, BD-10016, CML-593, CML-568 and BD-10234 demonstrated relatively drought tolerance during the germination and early seedling stages might be used in future breeding program. Ann. Bangladesh Agric. (2023) 27 (2): 19-30