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Carbon nanomaterials (CNMs), comprising carbon dots, graphene‐related materials, and carbon nanotubes, have significant potential for enhancing agricultural productivity. Their compositional compatibility and exceptional properties intrigue a great deal of explorations in agricultural applications, such as fertilizers, pesticides, and regulators of plant growth. However, the evaluation of their agricultural applicability often lacks quantitative sustainability metrics, with insufficient scrutiny on the carbon footprint and scalability of the manufacturing. This review attempts to provide a quantitative ranking system for evaluating the manufacturing processes of the CNMs by applying the twelve principles of Green Chemistry, particularly in the context of agriculture applications. The review also offers a systematically organized account of CNMs' effects on plant systems, encompassing nutrient enhancement, photosynthesis, soil amelioration, disease resistance, and phytotoxicity, which can provide design rationales for the further development of CNMs. [ABSTRACT FROM AUTHOR]

Chlorpyrifos has been used extensively for decades to control crop pests and disease-transmitting insects; its contribution to increasing food security and minimizing the spread of diseases has been well documented. Pymetrozine and Avermectin (also known as abamectin) have been used to replace the toxic organophosphate insecticides (e.g., Chlorpyrifos) applied to rice crops in China, where the overuse of pesticides has occurred. In addition, climate change has exacerbated pesticide use and pollution. Thus, farmers and communities are at risk of exposure to pesticide pollution. This study reviews the contamination, exposure, and health risks through environmental and biological monitoring of the legacy pesticide Chlorpyrifos and currently used insecticides Pymetrozine and Avermectin in China; it investigates whether changes in pesticide usage from Chlorpyrifos to Pymetrozine and Avermectin reduce pesticide contamination and health hazards to communities and residents. In addition, this review discusses whether Pymetrozine and Avermectin applications could be recommended in other countries where farmers largely use Chlorpyrifos and are exposed to high health risks under climate change scenarios. Although Chlorpyrifos is now banned in China, farmers and residents exposed to Chlorpyrifos are still experiencing adverse health effects. Local farmers still consider Chlorpyrifos an effective pesticide and continue to use it illegally in some areas. As a result, the concentration levels of Chlorpyrifos still exceed risk-based thresholds, and the occurrence of Chlorpyrifos with high toxicity in multiple environmental routes causes serious health effects owing to its long-term and wide application. The bioaccumulation of the currently used insecticides Pymetrozine and Avermectin in the environment is unlikely. Pymetrozine and Avermectin used in paddy water and soil for crop growth do not pose a significant hazard to public health. A change in pesticide use from Chlorpyrifos to Pymetrozine and Avermectin can reduce the pesticide contamination of the environment and health hazards to communities and residents. Finally, we recommend Pymetrozine and Avermectin in other countries, such as Vietnam, and countries in Africa, such as Ghana, where farmers still largely use Chlorpyrifos. [ABSTRACT FROM AUTHOR]

Pesticides play an important role in agricultural development. However, pesticide application can result in both acute and chronic human toxicities, and the adverse effects of pesticides on the environment and human health remain a serious problem. There is therefore a need to discuss the application methods for pesticides, the routes of pesticide exposure, and the health risks posed by pesticide application. The health problems related to pesticide application and exposure in developing countries are of particular concern. The purpose of this paper is to provide scientific information for policymakers in order to allow the development of proper pesticide application technics and methods to minimize pesticide exposure and the adverse health effects on both applicators and communities. Studies indicate that there are four main pesticide application methods, including hydraulic spraying, backpack spraying, basal trunk spraying, and aerial spraying. Pesticide application methods are mainly selected by considering the habits of target pests, the characteristics of target sites, and the properties of pesticides. Humans are directly exposed to pesticides in occupational, agricultural, and household activities and are indirectly exposed to pesticides via environmental media, including air, water, soil, and food. Human exposure to pesticides occurs mainly through dermal, oral, and respiratory routes. People who are directly and/or indirectly exposed to pesticides may contract acute toxicity effects and chronic diseases. Although no segment of the general population is completely protected against exposure to pesticides and their potentially serious health effects, a disproportionate burden is shouldered by people in developing countries. Both deterministic and probabilistic human health risk assessments have their advantages and disadvantages and both types of methods should be comprehensively implemented in research on exposure and human health risk assessment. Equipment for appropriate pesticide application is important for application efficiency to minimize the loss of spray solution as well as reduce pesticide residuals in the environment and adverse human health effects due to over-spraying and residues. Policymakers should implement various useful measures, such as integrated pest management (IPM) laws that prohibit the use of pesticides with high risks and the development of a national implementation plan (NIP) to reduce the adverse effects of pesticides on the environment and on human health. [ABSTRACT FROM AUTHOR]

• Soil nutrient index method was used to gain a comprehensive insight of soil nutrient characteristics of Tianshan Mountains. • The average soil nutrient indices of the western area were higher than those of the eastern area. • All nutrients except the total salts decreased with increasing depth. • The differentiations of soil nutrients and variation patterns were attributed to the vegetation type and coverage, altitude, and more importantly, to human activity. Soil nutrients are the basic properties and essential characteristics of the soil. Study of areal variability of soil nutrients is an important fundamental work for regional planning, environmental protection, and regionally sustainable development. Dynamic changes in soil nutrients are affected by factors such as soil type, fertilization, farming, irrigation, altitude, and climate. This study takes the Tianshan Mountains, located in the central region of Xinjiang, China, as this region is not only a hub for agriculture, industry, transportation, and tourism, but also it is crucial as a forest-grassland transition zone. Through field sampling, laboratory analysis and supported by statistical analysis, we investigated the soil nutrient characteristics and the soil nutrient index to gain a spatial image of soil nutrient status in Tianshan followed by the discussion of those influencing factors. We selected suitable locations along the forest-grassland transition zone to excavate pits of 40 cm × 40 cm in area and 100 cm in depth. A total of 133 soil samples were collected from 0–5 cm, 5–20 cm, and 20–40 cm in pairs (woodland, grassland). Five soil nutrients (soil organic matter (SOM), available nitrogen (AN), available phosphorus (AP), available potassium (AK) and total salts were selected for experimental, multivariate statistical, correlation and soil nutrient index analyses. The results show that (1) the average soil nutrient indices of the western area (M-T and K-B sites) were 0.5 and 0.24, respectively, higher than 0.2 of the eastern area (B-A site); (2) in soil layers of different depths of these three locations, all nutrients except the total salts (SOM, AN, AP, and AK) decreased with the increase in depth; (3) more fertile soils distribute in the western area (M-T and K-B sites) than in others of the Tianshan Mountains, showing higher soil nutrient contents and nutrient indices, abundant vegetation with greater diversity, higher vegetation coverage (80%-90%), and higher altitude. It can be concluded that the differentiation of soil nutrient index between western and eastern section of Tianshan were attributed to theirs' vegetation type and coverage, altitude, and more importantly, human activity.. [ABSTRACT FROM AUTHOR]

• Droughts increased CH 4 uptake in a wet year in the semiarid grassland. • Magnitude and pathways of drought effects on CH 4 uptake depend on seasonal timing. • Positive effects of early drought on CH 4 uptake were the least. • Plant composition regulated CH 4 uptake in response to droughts. Increasingly frequent and severe droughts are occurring in multiple seasons of a year in many dryland ecosystems, with unknown impacts on the role of drylands in cycling of methane (CH 4), a potent greenhouse gas. In particular, there is limited understanding of how drought occurring at different times within the growing season regulates biological CH 4 uptake, and how these responses are mediated by plant community composition. Here, we quantify how drought timing and plant community composition regulate CH 4 uptake in a semiarid grassland. We employ a field experiment in which droughts were imposed in early, middle, or late growing season in three different communities (two graminoids, two shrubs and their mixture), respectively. All three droughts increased CH 4 uptake, but the effect size and pathway varied with seasonal timing. Early and middle drought increased CH 4 uptake through increasing both soil pomA abundance and diffusivity resulting from reduced soil water content (SWC), while late drought increased CH 4 uptake only by reducing SWC. Overall, early drought had the least positive effects on CH 4 uptake because it excluded the least precipitation and therefore had smaller impacts on SWC. Besides, plant composition did not affect CH 4 uptake under normal environment but regulated CH 4 uptake in response to droughts due to different response of plant composition to droughts. Early and middle drought had larger positive effects on CH 4 uptake in shrub communities than the other two communities, consistent with larger reductions in SWC and larger increases in pomA abundance, respectively. In contrast, late drought had consistent effects on CH 4 uptake across three communities. Our results suggest that the magnitude and pathways of extreme drought effects on CH 4 uptake are strongly co-regulated by seasonal timing and plant composition. [ABSTRACT FROM AUTHOR]