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Microplastics threaten soil ecosystems, strongly influencing carbon (C) and nitrogen (N) contents. Interactions between microplastic properties and climatic and edaphic factors are poorly understood. We conducted a meta-analysis to assess the interactive effects of microplastic properties (type, shape, size, and content), native soil properties (texture, pH, and dissolved organic carbon (DOC)) and climatic factors (precipitation and temperature) on C and N contents in soil. We found that low-density polyethylene reduced total nitrogen (TN) content, whereas biodegradable polylactic acid led to a decrease in soil organic carbon (SOC). Microplastic fragments especially depleted TN, reducing aggregate stability, increasing N-mineralization and leaching, and consequently increasing the soil C/N ratio. Microplastic size affected outcomes; those <200 μm reduced both TN and SOC contents. Mineralization-induced nutrient losses were greatest at microplastic contents between 1 and 2.5% of soil weight. Sandy soils suffered the highest microplastic contamination-induced nutrient depletion. Alkaline soils showed the greatest SOC depletion, suggesting high SOC degradability. In low-DOC soils, microplastic contamination caused 2-fold greater TN depletion than in soils with high DOC. Sites with high precipitation and temperature had greatest decrease in TN and SOC contents. In conclusion, there are complex interactions determining microplastic impacts on soil health. Microplastic contamination always risks soil C and N depletion, but the severity depends on microplastic characteristics, native soil properties, and climatic conditions, with potential exacerbation by greenhouse emission-induced climate change.

The heavy metal cadmium (Cd) is known to be a widespread environmental contaminant and a potential toxin that may adversely affect human health across the globe. Green nanotechnology has recently received a lot of attention for developing eco-friendly, low-cost renewable and sustainable materials for the efficient removal of persistent contaminants from wastewater, including heavy metals (HMs). The current study compared the ability of titanium dioxide nanoparticles (TiO2NPs) synthesized from Trianthema portulacastrum(A) and Chenopodium quinoa(B) extracts to remove Cd from wastewater. The washed biomass of both the plants was dried under shade for a few days and was ground into the fine particles in a blender. The powdered biomass of T. portulacastrumand C. quinoawas soaked separately in distilled water (@ 10 g/100 ml) for 36 h. The stock solution of titanium (0.3 M) was prepared from concentrated titanium tetraisopropoxide (TTIP) and was mixed with the plant extracts at 1:2 ratio of extract to TTIP solution with continuous stirring at room temperature. A light brown scum like TiO2-NPs were obtained at the bottom of china dish and calcined at 450 °C for 4 h. Finally, after natural cooling, the TiO2-NPs were collected and used for the sorption of Cd through wastewater. Sorption attributes of both TiO2NPs (A, B) were investigated over contact time, dosage of adsorbent, pH, and initial concentration of Cd. Maximum sorption was obtained (46 mgg−1) by TiO2NPs (A), followed by 44 mg Cd g−1with TiO2NPs (B) at pH 4.2, an optimum adsorbent dosage 0.7 g L−1, Cd initial level 30 mg L−1, with contact time of 2 h. Pseudo-second-order kinetic model was suited for adsorption experimental data using both nanoparticles. These results validated the potential use of TiO2NPs to remove liquified cadmium at high concentrations from the industrial wastewater.

Declining soil fertility and crop yields are common in arid and semi–arid areas. Sustainable technologies that halt or reverse this trend are required to ensure food security. The use of compost for soil amendment should build soil resilience to drought. However, manure (which is a raw material in compost production) is used as a fuel in many semiarid regions of the world. To encourage farmers to change from using manure or composts as fuel to adopting them as soil additives, it will be necessary to demonstrate the production benefits associated with such additives. A 2‐yr field experiment was conducted in a semi‐arid (steppe) desert environment in Pakistan on sandy‐loamy soils. Poultry manure compost (PMC), pressmud compost (PrMC), and urea (U) were compared in a maize–maize (Zea maysL.) cropping system. The PMC and PrMC application increased soil organic carbon (SOC) and N as well as the soil's moisture content, but decreased the soil electrical conductivity (ECe) and pH after 2 yr. Replacing 25% of the U with PMC increased the mineral N and mean crop growth rate by 46%, the net assimilation rate by 30% and the yield by 219%, compared to the control. These results were comparable to applications of U alone and PMC with urea in a 25:75 application ratio. These results demonstrate that in semiarid regions, adding manure or compost as a soil additive improves the soil's yield potential. Core IdeasLess/no burning qualities manure can solve the conflict in using manure for energy.Compost can reverse soil fertility and maize yield decline in semiarid areas.Compost with urea at 25:75 can reduce 25% use of harmful mineral fertilizer. Less/no burning qualities manure can solve the conflict in using manure for energy. Compost can reverse soil fertility and maize yield decline in semiarid areas. Compost with urea at 25:75 can reduce 25% use of harmful mineral fertilizer.

Legume plants are an essential component of sustainable farming systems. Phosphorus (P) deficiency is a significant constraint for legume production, especially in nutrient-poor soils of arid and semi-arid regions. In the present study, we conducted a pot experiment to evaluate the effects of a phosphorus-mobilizing plant-growth promoting rhizobacterial strain Bacillus cereusGS6, either alone or combined with phosphate-enriched compost (PEC) on the symbiotic (nodulation-N2fixation) performance of soybean (Glycine max(L.) Merr.) on an Aridisol. The PEC was produced by composting food waste with addition of single super phosphate. The bacterial strain B. cereusGS6 showed considerable potential for P solubilization and mobilization by releasing carboxylates in insoluble P (rock phosphate)-enriched medium. Inoculation of B. cereusGS6 in combination with PEC application significantly improved nodulation and nodule N2fixation efficiency. Compared to the control (without B. cereusGS6 and PEC), the combined application of B. cereusGS6 with PEC resulted in significantly higher accumulation of nitrogen (N), P, and potassium (K) in grain, shoot, and nodule. The N:P and P:K ratios in nodules were significantly altered by the application of PEC and B. cereusGS6, which reflected the important roles of P and K in symbiotic performance of soybean. The combined application of PEC and B. cereusGS6 also significantly increased the soil dehydrogenase and phosphomonoesterase activities, as well as the soil available N, P, and K contents. Significant positive relationships were found between soil organic carbon (C) content, dehydrogenase and phosphomonoesterase activities, and available N, P, and K contents. This study suggests that inoculation of P-mobilizing rhizobacteria, such as B. cereusGS6, in combination with PEC application might enhance legume productivity by improving nodulation and nodule N2fixation efficiency.