Clean-soil Air Water最新文献

In a changing climate, conservation tillage and agronomic biofortification are essential for enhancing crop yield, nutritional security, carbon stocks, and soil quality. Consequently, a field study was conducted in central India to assess the short-term (4 years) effects of crop establishment techniques (CETs) and agronomic biofortification methods (ABMs) on soil health indicators, grain yield, and quality in the soybean–wheat cropping system. The experiment followed a split-plot design with two CETs in the main plots (permanent broad bed furrow, PBBF, and conventional tillage, CT) and eight ABMs, each with three replications. The results indicated that PBBF and ABMs (seed inoculation with the microbial strains MDSR 14 + MDSR 34, and soil and foliar application of Zn+Fe) improved soil carbon stock (by 49.6% and 52.4%), available nitrogen, phosphorus, potassium, available Zn (by 30.0%), and Fe (by 21.9%) after the fourth year of the study. Similarly, PBBF and microbial inoculation increased soil enzyme activities (dehydrogenase, acid phosphatase, and β-glucosidase), substrate-induced respiration, and microbial biomass carbon content. As a result, a higher soybean equivalent yield (5.59% higher in PBBF and 14.2% higher with foliar spray of Zn+Fe) and seed quality attributes (crude protein yield, grain Zn, and Fe) were observed in PBBF and the foliar spray of Zn and Fe treatments compared to CT and control, respectively. Overall, adopting the short-term PBBF system, microbial inoculation, and soil and foliar application of Zn and Fe improved rhizosphere biochemical properties, yield, and seed quality in the soybean–wheat system.

The degree and severity of zinc (Zn) deficiency in soil reduced the agricultural yield and quality, thus encouraging malnutrition in humans worldwide. The study was hypothesized to increase the bioavailability and release of Zn in soil and Zn biofortification in wheat grains under integrated nutrient management (INM). The long-term (54 years) experiment laid out in a split-plot design comprising single (W) and dual (PW) applications of farmyard manure (FYM) (0, 5, 10, and 15 Mg ha⁻¹) and nitrogen (0, 60, and 120 kg ha⁻¹) was studied to understand the distribution of different Zn fractions in soil and their relationship to wheat grain yield and Zn uptake. A laboratory incubation study was performed on surface soils to evaluate the release kinetics of native Zn at field capacity. The different fractions of Zn in soil increased with increasing frequency and levels of FYM application. Residual Zn constituted the maximum proportion (89.03%) of total soil Zn. A high positive correlation (p < 0.01) of diethylenetriaminepentaacetic acid (DTPA)-extractable Zn and total grain Zn content were observed with different Zn fractions. The release kinetics of native soil Zn increased up to 10 days and became almost constant, indicating the establishment of chemical equilibria between the soil solid and solution phase. Thus, long-term INM ensured higher wheat production (6.08 Mg ha⁻¹) and Zn biofortification (38.95 mg kg⁻¹) to combat Zn malnutrition and achieve the United Nations’ sustainable development goals on “zero hunger” and “good health and well-being.”

Short-cut nitrification (SCN) and denitrification (DN) technology is an efficient method for treating high-concentration nitrogen-containing wastewater. However, controlling the reaction conditions in single-reactor systems is difficult. In this study, SCN and DN were performed in separate reactors to investigate the influence of pH on SCN and the effect of carbon sources on DN. The results revealed that a combination of SCN and DN achieved a total nitrogen removal efficiency of 84%. Within a specific pH range (6.5–9.0), the accumulation of nitrite during SCN exhibited an initial increase, followed by a decrease, reaching a maximum at pH 8.5. In addition, this study established two experimental groups to investigate the effect of carbon sources on DN. The blank group (without the addition of a carbon source) exhibited a chemical oxygen demand (COD) concentration of 5.1 mg/L, whereas the control group (sodium acetate used as the carbon source) exhibited a COD concentration of 118.6 mg/L. These results indicate a substantial improvement in DN efficiency with the addition of a carbon source.

Environmental pollution caused by urbanization, agricultural intensification, and industrialization has led to an increase in the disposal of toxic effluents in aquatic environments. Most ecosystems in the world receive a variety of toxic metals (TMs) that exceed the capacity of water bodies to absorb or recycle them, thereby threatening aquatic and human life. Physicochemical remediation methods encounter problems because of the high cost, labor input, and use of chemicals with long residence times that later add toxic by-products. However, bioremediation techniques are a safe option for mitigating environmental pollution because of their high efficiency, cost-effectiveness, non-intrusiveness, eco-friendliness, ease of application, and social acceptance. Submerged and free-floating macrophytes were found to be more effective in the bioaccumulation of TMs than emergent macrophytes. Furthermore, most studies have suggested the use of macrophytes for the removal of TMs from water bodies; however, studies on the management of phytoremediated biomass are scarce. This review demonstrates the role of various macrophytes for the removal of TMs from water bodies and suggests techniques for the disposal and recycling of phytoremediated biomass with accumulated TMs. Further, the applications of genetically modified plants, nanotechnology, and native hyperaccumulators have been suggested as suitable candidates for greater efficiency of phytoremediation and appropriate management of TMs in the environment in the future.

The corrugated plate is the core component of a corrugated plate oil–water separator, which significantly influences oil–water separation efficiency. To study the influencing factors of oil droplets floating and coalescing on the lower surface of the corrugated plate, numerical simulation and experiments were used to analyze the effects of wave ratio, lower plate surface contact angle, oil viscosity, and oil droplet diameter on the floating of oil droplets on the coalescence of oil droplets. The results show that a moderate wave height ratio, lower contact angle, lower oil phase viscosity, and larger oil droplet diameter have better oil droplet agglomeration and floating effect. In the set parameter range, when the wave height ratio of the plate is 0.5, the contact angle of the lower surface of the plate is 30°, the oil phase viscosity is 0.0048 Pa s, and the oil droplet diameter is 8 mm, the oil droplet coalesces and floating effect are the best.