Antimony (Sb) is a serious toxic and non-essential metalloid for animals, humans, and plants. The rapid increase in anthropogenic inputs from mining and industrial activities, vehicle emissions, and shoot activity increased the Sb concentration in the environment, which has become a serious concern across the globe. Hence, remediation of Sb-contaminated soils needs serious attention to provide safe and healthy foods to humans. Different techniques, including biochar (BC), compost, manures, plant additives, phyto-hormones, nano-particles (NPs), organic acids (OA), silicon (Si), microbial remediation techniques, and phytoremediation are being used globally to remediate the Sb polluted soils. In the present review, we described sources of soil Sb pollution, the environmental impact of antimony pollution, the multi-faceted nature of antimony pollution, recent progress in remediation techniques, and recommendations for the remediation of soil Sb-pollution. We also discussed the success stories and potential of different practices to remediate Sb-polluted soils. In particular, we discussed the various mechanisms, including bio-sorption, bio-accumulation, complexation, and electrostatic attraction, that can reduce the toxicity of Sb by converting Sb-V into Sb-III. Additionally, we also identified the research gaps that need to be filled in future studies. Therefore, the current review will help to develop appropriate and innovative strategies to limit Sb bioavailability and toxicity and sustainably manage Sb polluted soils hence reducing the toxic effects of Sb on the environment and human health.

Cadmium (Cd), as the most prevalent heavy metal contaminant poses serious risks to plants, humans, and the environment. The ubiquity of this toxic metal is continuously increasing due to the rapid discharge of industrial and mining effluents and the excessive use of chemical fertilizers. Nanoparticles (NPs) have emerged as a novel strategy to alleviate Cd toxicity. Zinc oxide nanoparticles (ZnO-NPs) have become the most important NPs used to mitigate the toxicity of abiotic stresses and improve crop productivity. The plants quickly absorb Cd, which subsequently disrupts plant physiological and biochemical processes and increases the production of reactive oxygen species (ROS), which causes the oxidation of cellular structures and significant growth losses. Besides this, Cd toxicity also disrupts leaf osmotic pressure, nutrient uptake, membrane stability, chlorophyll synthesis, and enzyme activities, leading to a serious reduction in growth and biomass productivity. Though plants possess an excellent defense mechanism to counteract Cd toxicity, this is not enough to counter higher concentrations of Cd toxicity. Applying Zn-NPs has proven to have significant potential in mitigating the toxic effects of Cd. ZnO-NPs improve chlorophyll synthesis, photosynthetic efficiency, membrane stability, nutrient uptake, and gene expression, which can help to counter toxic effects of Cd stress. Additionally, ZnO-NPs also help to reduce Cd absorption and accumulation in plants, and the complex relationship between ZnO-NPs, osmolytes, hormones, and secondary metabolites plays an important role in Cd tolerance. Thus, this review concentrates on exploring the diverse mechanisms by which ZnO nanoparticles can alleviate Cd toxicity in plants. In the end, this review has identified various research gaps that need addressing to ensure the promising future of ZnO-NPs in mitigating Cd toxicity. The findings of this review contribute to gaining a deeper understanding of the role of ZnO-NPs in combating Cd toxicity to promote safer and sustainable crop production by remediating Cd-polluted soils. This also allows for the development of eco-friendly approaches to remediate Cd-polluted soils to improve soil fertility and environmental quality.

In response to the limitations of traditional double rice cropping models, this study constructed five typical rice planting models in the middle reaches of the Yangtze River, namely “Chinese milk vetch-early rice-late rice (CK/CRR), 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)” to study the annual emission characteristics of greenhouse gases under different planting models. The results showed the following: (1) From the perspective of total yield in two years, the CRI treatment reached its maximum, which was significantly higher than that of other treatments by 9.30~20.29% in 2019 (p < 0.05); in 2020, except for the treatment of RRI, it was significantly higher than other treatments by 20.46~30.23% (p < 0.05). (2) The cumulative emission of CH₄ in the double rice treatment is generally higher than that in paddy-upland rotation treatment, while the cumulative emission of N₂O in the paddy-upland rotation treatment is higher than that in the double rice treatment, but the total amount is much lower than the cumulative emission of CH₄. Therefore, CH₄ emissions from rice fields still occupy most of the GHGs. (3) The global warming potential (GWP) and greenhouse gas emission intensity (GHGI) of different planting patterns in rice fields in 2020 were higher than those in 2019, and the GWP and GHGI of double rice cropping treatment is higher than that of paddy-upland rotation treatments. During the two years, the GWP of CRR treatment reached its maximum and was significantly higher than that of other treatments by 48.28~448.90% and 34.43~278.33% (p < 0.05). The GHGI of CRR was significantly higher than that of CRI and RRI by 3.57~5.4 and 1.4~3.5 times (p < 0.05). Based on the comprehensive performance of greenhouse gas emissions over the two experimental years, RRI and CRI have shown good emission reduction effects, which can significantly reduce greenhouse gas emissions from paddy fields, are conducive to reducing global warming potential and greenhouse gas emission intensity and conform to the development trend of “carbon neutrality”. Therefore, considering high-yield, low-temperature chamber gas emissions, the Chinese milk vetch—early rice—sweet potato || late soybean model performs well and has the best comprehensive benefits. It is of great significance for optimizing the rice field planting mode in the middle reaches of the Yangtze River.

Soil aggregate stability is an important factor that impacts ecological restoration and soil erosion. Soil organic carbon (SOC) is also an important factor affecting soil characteristics and quality. The triple-cropping system has the potential to enhance soil aggregate stability by promoting a more diverse and continuous plant cover, which could lead to improved soil structure and resistance to erosion. Over two consecutive years, this study was conducted to explore the impacts of the triple-cropping system on soil aggregate stability, soil carbon pool, and carbon sequestration characteristics in the middle reaches of the Yangtze River. This study set up five planting modes, namely milkvetch–early rice–late rice (CRR, CK), milkvetch–early rice–sweet potato||soybean (CRI), rape–early rice–late rice (RRR), rape–early rice–sweet potato||soybean (RRI) and potato–early rice–late rice (PRR). The contribution of soil aggregates > 2 mm under CRI increased by 20.77%, 6.71%, and 2.19% to the control in winter cropping and early and late rice harvesting periods, respectively. During the winter harvest period, the geometric mean diameter (GMD) and mean weight diameter (MWD) of the CRI treatment were significantly higher than other treatments (p < 0.05), with increases of 7.53–16.28% and 4.67–10.28% respectively. After the late rice harvest, the GMD values of the CRI and PRR treatments were significantly higher than the control treatment by 13.56%, and the MWD values were higher than those of other treatments by 4.24–13.17%, 3.74–12.63% (p < 0.05). Furthermore, CRI also improved the GMD and MWD of soil aggregates, and the stability of soil aggregates was improved by winter milkvetch (treatment of CRI) and paddy-upland multi-crop models (treatment of PRR). RRR treatment was beneficial to the accumulation of soil organic carbon and slowed the loss of soil organic carbon. Irrigation and drought multiple cropping can effectively increase the content of soil active organic carbon, among which the treatment of CRI had the best performance and the most significant effect in increasing the content of soil active organic carbon. After the late rice harvest, the soil’s active organic carbon content in the CRI treatment was the highest, which was significantly different from the control treatment and increased by 35.62% compared with the control (p < 0.05). Compared with before planting, the soil microbial biomass carbon content in each treatment increased by 12.07–27.59% after the late rice harvest. The soil-dissolved organic carbon content in CRI treatment was the highest, which was significantly higher than CK treatment, RRR, and PRR, with an increase of 46.88%, 42.42%, and 30.56%, respectively (p < 0.05). In addition, the accumulation of soil microbial biomass carbon, soil dissolved organic carbon content, and soil easily oxidized organic carbon content was promoted by multi-cropping in rice fields, and the increase from CRI and RRI treatment was more significant. In conclusion, in the triple-cropping area of paddy fields in the middle reaches of the Yangtze River, the milkvetch–early rice–sweet potato||late soybean and rape–early rice–sweet potato||late soybean models are conducive to the optimal management of the soil carbon pool and carbon sequestration. These models can improve the multiple cropping index, reduce costs, and increase revenue.

Winter cropping is widely considered as an effective way to increase rice yield. Therefore, this study was performed to find optimal winter cropping patterns in middle and lower reaches of the Yangtze River, China. Five experimental treatments were set up based on the long-term field experiment including winter fallow (CK), Chinese milk vetch winter cropping pattern (CRR), rapeseed winter cropping pattern (RRR), garlic winter cropping pattern (GRR), and winter multiple cropping rotation (ROT). The effects of different winter cropping patterns on the yield, dry matter accumulation and translocation, and plant nitrogen uptake were explored in double-cropping rice. The results showed that compared with CK, winter cropping increased the early and late rice yield by 7.91-10.70% and 3.57-6.89%, respectively. Similarly, compared with CK, winter cropping patterns also increased the number of spikes in early rice by 19.36-25.81% and CRR and ROT increased the effective number of spikes in late rice by 25.58% and 23.26% respectively. The dry matter (DM) translocation by stem and leaf of early rice under CRR was highest, with a 36.2% increase compared with CK, however, DM accumulation after heading in early rice under CRR was lowest. GRR decreased the dry matter translocation by stem and leaf in early rice but increased DM accumulation after heading in early and late rice by 65.28% and 13.44% as compared to CK. Moreover, ROT increased the dry matter translocation by stem and leaf in late rice by 112.63%. Additionally, GRR and ROT treatments increased the stem nitrogen uptake in early rice by 61.76% and 58.61% as compared to control, while CRR increased the nitrogen uptake by stem, leave and spike in late rice by 40.76%, 49.51% and 42.92%. In conclusion, CRR is more beneficial to increase DM accumulation and translocation by stem and leaf in double-cropping rice, and nitrogen uptake by rice plants.

Mixed sowing of green manure in winter is a unique farming mode in southern China, which has the potential to replace or partially replace nitrogen fertilizer. To investigate how mixed sowing of green manure combined with nitrogen reduction regulates soil organic carbon and its fractions, this study was conducted in the 3/4 Chinese milk vetch × 1/4 rapeseed farming mode, without nitrogen fertilizer (CK), 100% N fertilizer (150 kg ha⁻¹, N1MR), 20% N fertilizer reduction (120 kg ha⁻¹, N2MR), 40% N fertilizer reduction (90 kg ha⁻¹, N3MR), and 60% N fertilizer reduction (60 kg ha⁻¹, N4MR). The main results were the N2MR treatment could guarantee stable and increased rice yield. The N1MR and N2MR treatments were more conducive to the accumulation of TOC. The N4MR and N2MR treatments were more conducive to the increase and accumulation of AOC and DOC. The effective spikes were positively correlated with TOC and ROC. The grain number per panicle was positively correlated with DOC. The seed-setting rate was positively correlated with ROC. Overall, mixed sowing of Chinese milk vetch and rapeseed combined with 20% nitrogen reduction ensures a stable yield and increase in rice. Nitrogen reduction by 60% and 20% is beneficial to the increase and accumulation of TOC, AOC, and DOC in soil.