Soil contamination with arsenic (As) is becoming a serious concern for living organisms. Arsenic is a nonessential metalloid for plants, humans, and other living organisms. Biochar (BC) is a very effective amendment to remediate polluted soils and it received great attention owing to its appreciable results. Arsenic toxicity negatively affects plant morph-physiological and biochemical functioning and upsurges the generation of reactive oxygen species (ROS), which negatively affect cellular structures. Arsenic toxicity also reduces seed germination and impedes plant growth by decreasing nutrient uptake, causing oxidative damage and disrupting the photosynthetic efficiency. Plants use different strategies like antioxidant defense and increased osmolyte synthesis to counteract As toxicity; nevertheless, this is not enough to counter the toxic impacts of As. Thus, applying BC has shown tremendous potential to counteract the As toxicity. Biochar application to As-polluted soils improves water uptake, maintains membrane stability and nutrient homeostasis, and increases osmolyte synthesis, gene expression, and antioxidant activities, leading to better plant performance. Additionally, BC modulates soil pH, increases nutrient availability, causes As immobilization, decreases its uptake and accumulation in plant tissues, and ensures safer production. The present review describes the sources, toxic impacts of As, and ways to lower As in the environment to decrease its toxic impacts on humans, the ecosystem, and the food chain. It concentrates on different mechanisms mediated by BC to alleviate As toxicity and remediate As-polluted soils and different research gaps that must be fulfilled in the future. Therefore, the current review will help to develop innovative strategies to minimize As uptake and accumulation and remediate As-polluted soils to reduce their impacts on humans and the environment.

Maize (Zea mays L.), an important crop used for animal feed and human consumption, is currently threatened by water shortage. Recently, the usage of nanomaterials has attracted worldwide attention due to their applications in various fields. This research aimed to evaluate the comparative efficacy of different metal oxide nanoparticles for mitigating drought stress in maize. Iron oxide, manganese oxide, and copper nanoparticles were biosynthesized from the leaf extract of Conocarpus erectus L. and characterized via UV-Vis, XRD, FTIR, and SEM. The synthesized nanomaterials were initially optimized at different concentrations (0, 25, 50, 75, and 100 ppm). The optimized doses of each nanoparticle were then applied to maize plants under different drought stress levels (50% FC, 75% FC, and 100% FC). Compared to the control, the application of nanomaterials significantly improved the growth parameters of the maize by 30% at 50% FC, 27% at 75% FC, and 26% at 100% FC. The chlorophyll content also improved significantly at different levels of drought stress by 35%, 32%, and 29% as compared to the control, respectively. The antioxidants (CAT, POD, SOD, and APX) also improved significantly at different levels of drought by 37%, 34%, and 31%, as compared to control, respectively. Moreover, the use of nanoparticles resulted in a significant decrease in cellular oxidative stress (MDA, H2O2) parameters by 23% at 50%FC, 26% at 75% FC, and 27% at 100% FC. Biosynthesized FeO NPs, MnO NPs, and Cu NPs have demonstrated significant potential in mitigating drought stress in maize, suggesting a promising approach to enhance crop performance under water-limited conditions. Further research is recommended to explore the long-term impacts and practical applications of these findings in sustainable agriculture.

The present experiment aimed to examine the impact of nano urea (NU) and plant growth-promoting rhizobacteria (PGPR) on Reshmi amaranth (Amaranthus tricolor) growth under salt stress. Experiments were conducted using six different combinations of NaCl, NU, and PGPR for 35 days under greenhouse conditions. The results showed that salinity stress significantly (p < 0.05) reduced plant growth parameters, including shoot height, root length, fresh weight, and leaf area. However, the application of NU and PGPR, both individually and in combination, enhanced plant growth and physiological resilience under saline conditions. The NU + PGPR treatment yielded the best improvements, with a shoot height of 42.25 cm, root length of 34.79 cm, and fresh weight of 61.69 g, indicating a synergistic effect. Biochemical analysis showed that NaCl stress lowered chlorophyll (0.25 mg/g fwt.) and carotenoids (60.17 µg/100 g) and disrupted ionic homeostasis by increasing Na⁺ accumulation while reducing K⁺ and Ca²⁺ uptake. The combined NU and PGPR treatment restored ionic balance, with Na⁺ reduced to 58.12 mg and K⁺ and Ca²⁺ levels increasing to 115.25 mg and 78.70 mg, respectively. Stress markers such as malondialdehyde (MDA) and proline also showed significant reductions, while antioxidant enzyme activities stabilized under NU and PGPR application. Thus, this study indicated that NU and PGPR mitigate salt-induced stress by improving nutrient assimilation, promoting osmotic regulation, and enhancing antioxidative defenses in Reshmi amaranth.

To explore the characteristics of soil microbial community structure diversity for different planting patterns in paddy fields, and to screen out the planting patterns suitable for the promotion of double-cropping rice areas in the middle reaches of the Yangtze River, five typical planting patterns were set up in this study. The five patterns are Chinese milk vetch–early rice–late rice (CRR, CK), Chinese milk vetch–early rice–sweet potato || late soybean (CRI), rapeseed–early rice–late rice (RRR), rapeseed–early rice–sweet potato || late soybean (RRI) and potato–early rice–late rice (PRR). The variation characteristics of soil microbial community structure diversity and the correlation between soil environmental factors and soil microbial community structure diversity under the triple-cropping system in the double-cropping rice area of the middle reaches of the Yangtze River were studied by 16S rRNA high-throughput sequencing and real-time fluorescence quantitative polymerase chain reaction (PCR). The results showed that after two years of experiment, the pH values of each treatment increased, and the rapeseed–early rice–late rice (RRR) model performed better. The soil organic matter and total nitrogen content of the milk vetch–early rice–sweet potato || late soybean (CRI) model was the highest, which increased by 7.89~35.02% and 6.59~26.80% compared with other treatments. The content of soil available phosphorus and available potassium in the potato–early rice–late rice (PRR) model was higher than that in other treatments, which was increased by 29.48% and 126.49% compared with the control. The Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–sweet potato || late soybean (RRI) models were beneficial to increasing soil nitrate nitrogen and ammonium nitrogen content. Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–late rice (RRR) patterns were beneficial for improving the microbial diversity index. Proteobacteria, Chloroflexi, and Actinobacteria are the top three dominant phyla in terms of the relative abundance of soil bacteria, and the top three dominant fungi are Ascomycota, Basidiomycota, and Mucor. The Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–sweet potato || late soybean (RRI) patterns increased the relative abundance of soil Actinobacteria and Ascomycota. The contents of ammonium nitrogen, total organic carbon, nitrate nitrogen, and available phosphorus were the main environmental factors affecting soil microbial community structure. The findings can provide references for screening out the planting patterns suitable for the promotion of double-cropping rice areas in the middle reaches of the Yangtze River.