Contrary to the constraints in time, investment, and management of the traditional technology for waste water treatment, this paper seeks to propose a more advanced, reliable, and affordable new technology to restore urban polluted rivers to pristine quality levels. The paper also presents new ideas on the selection and use of microbial agents to improve the efficiency of pollution removal. It presents the successful implementation of microbial technology (MT) on Chengnan River, which was heavily polluted before MT implementation. Without artificial aeration, sediment dredging, or complete sewage interception, we directly sprayed a previously configured HP-RPe-3 Microbial Agent into the water body and sediment. We considered the feasibility of MT for treating polluted urban rivers from the perspective of several water quality indices evaluation methods. After the treatment, the concentration of dissolved oxygen (DO) reached 5.0 mg/L, the removal rates of ammonia nitrogen (NH 3 -N) and chemical oxygen demand (COD) reached 20% and 38% respectively, and the average degradation rate of total phosphorus (TP) along river was close to 15%. Also, the Nemerow Index of the river was reduced from 2.7 to 1.9. The Fuzzy Comprehensive Index shows a tendency for improvement from Inferior Grade V to a better grade (approximately Grade III). The color of the river water changed, from black or dark green, to its original color. The results indicate that the bioremediation technology of directly adding microbial agents mainly aimed for the degradation of NH 3 -N can preliminarily eliminate the black-odor phenomenon of urban rivers, and improve their water quality. It is expected that the MT application, and the concept of how to select the corresponding microbial agents according to main pollutants, can be widely accepted and applied to similar cases.
Nitrogen (N) affects all levels of plant function from metabolism to resource allocation, growth, and development and Magnesium (Mg) is a macronutrient that is necessary to both plant growth and health. Radish ( Raphanus sati vus L.) occupies an important position in the production and consumption of vegetables globally, but there are still many problems and challenges in its nutrient management. A pot trial was conducted to investigate the effects of nitrogen and magnesium fertilizers on radish during the year 2018–2019. Nitrogen and magnesium was applied at three rates (0, 0.200, and 0.300 g N kg −1 soil) and (0, 0.050, and 0.100 g Mg kg −1 soil) respectively. The experiment was laid out in a completely randomized design (CRD) and each treatment was replicated three times. Growth, yield and quality indicators of radish (plant height, root length, shoot length, plant weight, total soluble sugar, ascorbic acid, total soluble protein, crude fiber, etc.) were studied. The results indicated that different rates of nitrogen and magnesium fertilizer not only influence the growth dynamics and yields but also enhances radish quality. The results revealed that the growth, yield and nutrient contents of radish were increased at a range of 0.00 g N. kg −1 soil to 0.300 g N. kg −1 soil and 0.00 g Mg. kg −1 soil to 0.050 g Mg. kg −1 soil and then decreased gradually at a level of 0.100 g Mg. kg −1 soil. In contrast, the crude fiber contents in radish decreased significantly with increasing nitrogen and magnesium level but increased significantly at Mg 2 level (0.050 g Mg. kg −1 soil). The current study produced helpful results for increasing radish quality, decreasing production costs, and diminishing underground water contamination.
Composting is the most adaptable and fruitful method for managing biodegradable solid wastes; it is a crucial agricultural practice that contributes to recycling farm and agricultural wastes. Composting is profitable for various plant, animal, and synthetic wastes, from residential bins to large corporations. Composting and agricultural waste management (AWM) practices flourish in developing countries, especially Pakistan. Composting has advantages over other AWM practices, such as landfilling agricultural waste, which increases the potential for pollution of groundwater by leachate, while composting reduces water contamination. Furthermore, waste is burned, open-dumped on land surfaces, and disposed of into bodies of water, leading to environmental and global warming concerns. Among AWM practices, composting is an environment-friendly and cost-effective practice for agricultural waste disposal. This review investigates improved AWM via various conventional and emerging composting processes and stages: composting, underlying mechanisms, and factors that influence composting of discrete crop residue, municipal solid waste (MSW), and biomedical waste (BMW). Additionally, this review describes and compares conventional and emerging composting. In the conclusion, current trends and future composting possibilities are summarized and reviewed. Recent developments in composting for AWM are highlighted in this critical review; various recommendations are developed to aid its technological growth, recognize its advantages, and increase research interest in composting processes.
The challenging impact of drought to agricultural productivity requires the adoption of mitigation strategies with a better understanding of underlying mechanisms responsible for drought tolerance. The present study aimed at investigating the effects of sulfur-based fertilizers on mitigation of drought stress in sunflower. Sulfate-containing fertilizers, viz., ammonium sulfate, zinc sulfate, magnesium sulfate, potassium sulfate, and gypsum, were initially evaluated at two different rates (10 and 20 mg kg−1 soil equivalent to 20 and 40 kg ha−1, respectively) for nutrient uptake and growth-promoting traits in sunflower seedlings (cv. Hysun-33). The best performing fertilizer (gypsum) was then selected to evaluate the response of sunflower under drought stress imposed at flowering stage for three weeks (25–30% water holding capacity). Results indicated significant amelioration of drought stress with higher activity of photosynthetic apparatus, upregulation of antioxidative enzymes, and increased achene yield by gypsum application. In comparison to control, gypsum-treated plants (20 mg kg−1 soil) exhibited higher water status (32%), leaf photosynthetic rate (29%), transpiration rate (67%), and stomatal conductance (118%) under drought stress. The antioxidant enzyme activities of catalase, guaiacol peroxidase, and superoxide dismutase were also increased by 67%, 62%, and 126%, respectively, resulting in higher achene yield (19%) under water-deficit conditions. This study indicates that the application of sulfur-based fertilizers (gypsum) can be used to induce drought tolerance and obtain high sunflower yields under drought stress, and furthermore, it is a cost-effective strategy resulting in high benefit–cost ratio with respect to no gypsum application.
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