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Microplastics (MPs) have emerged as a widespread environmental contaminant, raising growing concerns about their impact on terrestrial ecosystems. This comprehensive review paper highlights the effects of MPs on soil properties, soil organisms, and plants, shedding light on the complex interactions within these critical components of terrestrial environments. In terms of soil properties, plastics, ranging from macroplastics to mesoplastics, microplastics, and nanoplastics, have been found to exert significant influence. They can alter soil physical attributes, including texture, structure, bulk density, water aggregate stability, water holding capacity, and rainwater infiltration. Microplastics can affect soil chemical properties by influencing pH levels, electrical conductivity (EC), nutrient cycling, and enzyme activity, and even can cause heavy metal accumulation in plants. These alterations in soil properties have far-reaching implications for ecosystem health and agricultural productivity. Furthermore, microplastics have substantial repercussions on soil organisms, particularly earthworms, collembolans, and microbial communities comprising bacteria and fungi. These organisms play pivotal roles in nutrient cycling and soil health. Microplastics can disrupt their habitats, affect their behavior, and potentially lead to changes in soil biota composition, with widespread effects throughout the terrestrial food web. Microplastics influence plant growth and development; even the microplastic can be uptaken and translocated within plant tissues. Food safety and ecosystem dynamics are affected by these effects. This review paper emphasizes the urgency of understanding the complex interactions between microplastics and terrestrial ecosystems. It highlights the need for further research to comprehensively assess the extent and implications of microplastic contamination in various soil types, under different environmental conditions, and concerning diverse plastic characteristics. Standardized methodologies for studying these interactions are essential to facilitate comparisons across studies.
Nitrogen (N) is an essential and limiting nutrient for crop production, as it is a structural part of plants and is involved in various processes. Worldwide, agricultural soils lack one or more essential nutrients, and nitrogen is one of them. Adding a sufficient amount of N will increase production. However, the overuse of N and loss of N from the soil-plant system is detrimental to the environment and results in economic losses. Nitrogen has reactive forms like ammonia, ammonium, nitrate, nitrite, nitric oxide, and nitrous oxide. Some reactive forms of N are harmful to humans, animals, plants, and microbial ecology. Nitrate can cause the eutrophication of surface water and contamination of groundwater. Drinking nitrate-contaminated water can cause methemoglobinemia and other health issues. Nitrous oxide emission depletes the ozone layer and contributes to climate change. Ammonia emissions contribute to acid rain and are also responsible for nitrous oxide emissions. This review addresses different factors/pathways/circumstances that contribute to the loss of N from the soil-plant system and reduce nitrogen use efficiency (NUE). Different factors influence NUE like ammonia volatilization, nitrification, denitrification, immobilization, leaching, runoff, temperature, soil pH, soil texture, rainfall and irrigation, soil salinity, tillage, weeds, pests, diseases, N loss from plants, fires, crop rotation, crop nutrition, crop varieties, and nitrogen management (right time, right source, right place, and right rate/amount).
Seed dormancy impacts seed germination success and seedling health. Ethylene plays a crucial role in facilitating the breaking of seed dormancy by initiating essential biochemical and physiological changes that are necessary for successful seed growth and development. It was hypothesized that acetylene (C2H2) from calcium carbide (CaC2) has the potential to induce an ethylene response in seed for breaking seed dormancy and better seedling growth. A study was conducted to evaluate the impacts of C2H2 released from ten CaC2 concentrations, i.e., 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20 mg petri-plate-1, on seed dormancy and seedling growth in sweet pepper. Results indicated that CaC2 significantly induced 100% early seed germination, with significant improvements in post-germination variables. CaC2 applied at 14 mg petri-plate-1 was found to be an optimum dose for regulating seed dormancy and post-germination growth positively. However, CaC2 >16 mg petri-plate-1 proved lethal and suppressed the germination or growth of the seedlings. Compared to control treatment, improvements in seed sermination and growth variables, i.e., 8 to 37% in seed germination, 5 to 22% in seedling biomass, 5 to 46% in shoot length, and 3 to 37% in root length, suggest that calcium carbide, easily available on the market, can be used for seed dormancy breakage and better crop stand.
Pesticides are indispensable for successful vegetable production; however, misuse of insecticides results in chemical pollution and entry into the food chain. This study uniquely addresses the quantification of pesticide residues in cauliflower curds and soil, and associated human health risks in the specific climatic conditions of Multan City, and it is the first to collectively examine these five (lufenuron, bifenthrin, emamectin benzoate, metalaxyl, and mancozeb) pesticides in cauliflower. A survey of the cauliflower production area was performed to collect information about pesticides used for insect pest and disease management. Farmers were applying lufenuron, bifenthrin, emamectin benzoate, metalaxyl, and mancozeb. The cauliflower plant and soil samples were collected with the frequency of 1, 3, 5, 7, and 15 days after the application of pesticides. The collected plant and soil samples dried and extracted to determine pesticide residues using the modified QuECHERS method. Pesticides residues assessment was performed on High performance liquid chromatography (HPLC) at the Pesticide Quality Control Laboratory, Multan. There were no pesticide residues were detected in the soil samples. While in the cauliflower 20% samples (out of 40 samples) contained pesticide residues. Initial deposits of lufenuron of 0.93, 3.19, and 5.63 ppm were detected in the cauliflower samples of day 1 (after pesticide application) from the fields of farmers 1, 4, and 8, respectively. Bifenthrin residues of 1.64 and 1.78 ppm were detected in the cauliflower samples of day 1 (after pesticide application) from the fields of farmers 1 and 8, respectively. Similarly, bifenthrin residues of 0.81 and 0.61 ppm were detected in the cauliflower samples of day 3 (after pesticide application) from the fields of farmers 1 and 8. Bifenthrin residues were also detected in the 5th day sample (0.41 ppm) from the fields of farmer 8. While performing the risk assessment it was revealed that there will be no health risk associated for an average body weight (60 kg) person with the cauliflower consumption.
Cotton production in Pakistan is often constrained by limited water resources and inadequate potassium (K) fertilization, leading to lower crop resilience and yield. This study aimed to evaluate the ameliorated effect of potassium on cotton under drought stress and the climatic conditions of Multan by assessing the potassium (K) use efficiency and related physiological attributes in cotton cultivars with varying K efficiency. Moreover, we aimed to identify the K-efficient cotton cultivar to provide a helping hand for breeders in developing high-yielding varieties for low K and water-limiting environments. For this purpose, five cotton cultivars (FH-142, IUB-2013, CIM-554, CYTO-124 [K-efficient], and BH-212 [K non-efficient]) were evaluated under two irrigation regimes (reduced and normal) with a standardized K application (50 kg ha-1) across two growing seasons. Under reduced irrigation with applied K, the K-efficient cultivar FH-142 displayed significantly improved agronomic and physiological K use efficiency compared with the K non-efficient cultivar BH-212. Specifically, FH-142 exhibited 67.3% and 62.5% increases in agronomic and physiological use efficiency, respectively, compared with BH-212. Potassium application under normal irrigation generally increased chlorophyll content across all cultivars, with the greatest improvement observed in FH-142 (7.2%). Reduced irrigation with K application increased leaf osmotic potential in all cultivars, indicating improved drought tolerance. However, the magnitude of this increase varied, with BH-212 showing the highest rise (16.2%) and FH-142 exhibiting moderate increase (7.3%). Interestingly, K application under reduced irrigation mitigated membrane leakage, a measure of cell damage, in all cultivars except BH-212. Notably, BH-212 displayed higher membrane leakage (14.2%) than K-efficient cultivars (3.0% - 9.0%). Overall, the K- K-efficient cultivars’ performance order differs from FH-142< CIM-554< CYTO-124< IUB-2013. The key findings highlight the importance of potassium for mitigating the negative effects of water stress on cotton plants. Several cultivars, including FH-142, CIM-554, CYTO-124, and IUB-2013, demonstrated superior performance under both irrigation levels with and without potassium application, suggesting their potassium-efficient nature. FH-142 outperformed other cultivars under water stress with K application, demonstrating exceptional potassium recovery efficiency and reinforcing its suitability for drought-prone, K-deficient soils. These findings suggest that selecting K-efficient cotton cultivars like FH-142, CYTO-124, IUB-2013, and CIM-554 could improve cotton resilience and yield under limited water and K availability, aiding farmers and supporting breeders in developing high-yield, drought-tolerant varieties
Soil pollution in urban environments is a critical issue with significant implications for public health, environmental quality, and sustainable urban development. This review paper explores the various aspects of soil pollution in urban areas, including its sources, types of pollutants, consequences, mitigation strategies, and the importance of sustainable urban development. The sources of soil pollution in urban environments are diverse, ranging from industrial activities and waste disposal to emerging sources like microplastics and pharmaceuticals. The types of pollutants found in urban soils include heavy metals, polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides, among others. The consequences of soil pollution in urban areas encompass public health risks, environmental impacts, and contamination of water resources. Mitigation strategies such as remediation techniques, pollution prevention measures, urban green infrastructure, and public awareness are crucial for addressing soil pollution in urban environments. Sustainable urban development plays a key role in maintaining soil health and integrating soil considerations into urban planning. By understanding the sources, types, consequences, and mitigation strategies of soil pollution in urban areas, cities can work towards healthier environments and sustainable development.
As climate change intensifies, the agricultural sector faces escalating challenges in maintaining productivity and environmental sustainability. Among emerging strategies to enhance climate resilience, silicon (Si) has gained attention for its multifaceted role in soil and plant systems. This review synthesizes current scientific understanding of silicon-mediated mechanisms that contribute to climate change mitigation and crop improvement. Silicon enhances soil physical stability through increased aggregation and improved water retention, stimulates beneficial microbial activity, and modifies soil chemistry by optimizing pH and nutrient availability. Mechanistically, silicon contributes to carbon sequestration via phytolith formation and phytolith-occluded carbon (PhytOC), a long-term stable carbon pool in soils. It also mitigates greenhouse gas emissions by reducing methane (CH₄) through enhanced methanotrophic activity, lowering nitrous oxide (N₂O) emissions via pH regulation and improved nitrogen use efficiency, and indirectly minimizing CO₂ release through greater carbon stabilization. Furthermore, Si strengthens plant tolerance to abiotic stresses such as drought, salinity, heat, and heavy metals, as well as biotic stresses from pests and pathogens, primarily through the activation of antioxidant enzymes and structural fortification of tissues. Overall, this review highlights silicon as a pivotal element for integrating soil–plant–atmosphere processes, offering a sustainable strategy to enhance climate resilience, reduce greenhouse gas emissions, and improve global crop productivity.
