Search Results (294)

Not all produced compost meets established quality standards, often resulting in environmental challenges. This study investigated the potential of using mature compost as a feedstock for biochar production, with a focus on evaluating the gas adsorption properties of the resulting biochars. Mature compost was utilized as a substrate, and the pyrolysis process involved heating samples within a temperature range of 400–650 °C, at 50 °C intervals, with heating rates of 10 °C·min⁻¹, 15 °C·min⁻¹, or 20 °C·min⁻¹ for a duration of 60 min. The resulting biochars were tested for their adsorption performance against a synthetic gas mixture simulating composting emissions (CO₂, CO, H₂S, NH₃, CH₄ in N₂). Our findings reveal a significant correlation between the pyrolysis temperature and the sorption characteristics of compost biochars. Specifically, biochars produced at temperatures of 550 °C, 600 °C, and 650 °C (with a heating rate of 10 °C·min⁻¹) demonstrated the highest efficacy in reducing emissions of CO₂, CH₄, and H₂S, achieving reductions of 69%, 69%, and 72%, respectively. However, these biochars exhibited lower adsorption capacity for CO and NH₃. Interestingly, biochars produced at 400 °C and 450 °C showed enhanced performance for CO adsorption. Compost biochar shows strong potential for gas adsorption, particularly for CO, CO₂, and H₂S. Due to its pronounced CH₄ sorption capacity, such biochar is better suited for mitigating emissions during composting rather than for biogas purification. Full article

Organic amendments provide a sustainable strategy to enhance soil quality in degraded environments while also helping to reduce greenhouse gas emissions, for example, by improving soil structure, minimizing the use of synthetic fertilizers, and promoting a green economy. This study assessed the comparative effects of two organic amendments—vermicompost leachate and biochar—on the performance of popcorn maize (Zea mays L. var. everta) cultivated in saline soil conditions. Four treatments were evaluated: T0 (Control), T1 (Vermicompost leachate), T2 (Biochar), and T3 (Vermicompost leachate + Biochar), each with 10 replicates arranged in a Completely Randomized Design (CRD). Although various soil physicochemical, microbiological, and agronomic parameters displayed no significant differences compared to the control, the application of biochar resulted in considerable improvements in soil total organic carbon, the microbial community (mesophilic aerobic bacteria, molds, and yeasts), and increased seed length and diameter. In contrast, vermicompost leachate alone negatively impacted plant growth, leading to decreases in leaf area, stem thickness, and grain yield. Specifically, grain yield declined by 46% with leachate alone and by 31% when combined with biochar, compared to the control. These findings emphasize the superior effectiveness of biochar over vermicompost leachate as a soil amendment under saline conditions and highlight the potential risks of widely applying compost teas in stressed soils. It is recommended to conduct site-specific assessments and screenings for phytotoxins and phytopathogens prior to use. Additionally, the combined application of leachate and biochar may not be advisable given the tested soil characteristics. Full article

Exploiting clay for brick production results in soil damage. There are no field evaluations for its recovery with organic amendments comprising biochar. We conducted a small-scale experiment to assess the recovery effects of soil using biochar, both alone and in combination with compost. On a remnant of soil from clay mining, we applied the following to plots of 2.25 m² in a randomized complete block design: (1) biochar + efficient microorganisms (EMs), (2) compost + EMs, (3) compost + biochar + EMs, and (4) a control group without amendments. Composite soil samples from each plot were collected at the beginning of the experiment and at 30, 120, and 210 days. We analyzed some physicochemical properties of the soil and recorded the number and morphotypes of seedlings. We found that biochar + EMs and biochar + compost + EMs had positive effects in the short term, particularly in reducing bulk density. No synergistic effect was observed between biochar and compost, contrary to what was expected, which may be due to the short term of the experiment and prevailing low temperatures. The compost + EM treatment resulted in greater seedling diversity. In conclusion, bulk density can be used as an early indicator of soil improvement when biochar alone or combined with compost is used. Biochar may be a striking solution for promoting sustainable soil management after clay mining in high-elevation conditions. Full article

This study investigates biochar-enriched organic fertilizers made from bagasse, ash, spent wash, and cane tops, assessing their impact on corn growth over 45 days. A randomized complete block design with three replicates was used, testing six formulations with biochar levels at 0%, 10%, and 20%, along with soil-only and commercial fertilizer controls. Treatments T5 (bagasse + ash + spent wash + cane tops), T11 (T5 + 10% biochar), and T17 (T5 + 20% biochar) showed the best results for plant height, leaf development, and biomass production, with T17 performing the best for growth, biomass, and girth. The biochar in T17 had a pH of 9.37 ± 0.16, 18.00 ± 1.25% ash content, and a surface area of 144.58 m²/g. Nutrient analysis of the compost showed 2.85% potassium, 1.12% phosphorus, 1.85% nitrogen, 4.1% calcium, 0.23% magnesium, and 130 mg/kg zinc. The elemental composition was 68.50% carbon, 4.50% hydrogen, 6.00% nitrogen, and 25.30% oxygen, with 85.00% total organic carbon (TOC). This study concludes that T17 is the most effective formulation, offering both environmental and financial benefits, with composting potentially generating $11.16 million in profit, compared to the $19.32 million spent annually on waste management in Sri Lanka’s sugar industry. Full article

Heavy metal (HM) contamination poses a major threat to environmental health, agriculture and human well-being, requiring effective and sustainable remediation strategies. Phytoremediation, an eco-friendly and cost-effective approach, is widely used for the remediation of HM-contaminated soils. Although phytoremediation holds considerable potential in the extraction, stabilisation and degradation of HMs, its effectiveness is often constrained by limited metal bioavailability, plant stress under toxic conditions and slow metal uptake rates. To address these limitations, this review examines the integration of various soil amendments—the application of biochar, compost, plant exudates, microbial agents and chelating agents—to enhance phytoremediation efficiency. This review critically evaluates empirical evidence on the effectiveness, scalability, economic feasibility and environmental impact of these amendments. By synthesising recent studies, this review advances the understanding of amendment-assisted phytoremediation as a viable solution for treating HM-contaminated soils. In addition, this review identifies practical applications, discusses limitations and explores the potential synergies of these amendments to optimise phytoremediation strategies, ultimately contributing to more effective and sustainable environmental cleanup efforts. Full article

With increasing emphasis on sustainable horticulture, optimizing substrate composition is essential to reduce peat usage in container production. This study evaluated the effects of biochar and compost amendments on the growth and nutrient status of cherry laurel (Prunus laurocerasus) in two separate experiments conducted over five months. Experiment I assessed growth in pure peat and in peat–compost blends at volume ratios of 100:0, 70:30, 50:50, 30:70 and 0:100. Experiment II investigated the effect of adding biochar to a pure peat substrate at rates of 3 g·dm⁻³ and 5 g·dm⁻³. Key parameters were monitored, including the above and below-ground biomass, leaf and shoot counts, chlorophyll content, and the chemical composition of plant tissue and substrate. Compost addition increased the substrate pH from ~4.6 to ~6.4, while electrical conductivity increased with a higher compost content, reaching values approximately 2–3 times greater than in pure peat. Nutrient levels (Ca, K, Mg, P, NO₃⁻) also rose consistently with an increasing compost share. While a higher compost content generally reduced the biomass, leaf and shoot number, the greatest plant height and relatively favorable biomass were observed at 30% and 50% compost mixtures. Biochar addition slightly increased plant height, while the total biomass, root mass, and shoot number tended to decrease compared to pure peat, particularly at the lower biochar dose (3 g·dm⁻³). The substrate pH remained relatively stable, whereas electrical conductivity (EC) showed a slight upward trend with increasing biochar levels. Biochar also slightly increased the substrate nutrient content (Ca, K, Mg, P, NO₃⁻). Full article

Labile organic carbon (OC), a dynamic component of soil organic carbon (SOC), is essential for improving soil health, fertility, and crop productivity, particularly when organic and inorganic amendments are combined. However, limited research exists on the best amendment strategies for restoring degraded gleyic solonetz soggy sodic (GSSS) soils in West Africa’s coastal zones. A three-year field study (2017–2019) assessed the effects of various combinations of organic (mature or composted cow dung, with or without biochar) and inorganic inputs on soil organic carbon fractions, total carbon stocks, and the Carbon Management Index (CMI) in GSSS soils of Sege, Ada West District, Ghana. The results showed that organic and inorganic combinations outperformed the sole inorganic NPK treatment and the control, particularly in the topsoil. Composted cow dung with mineral fertilizer (CCfert) was especially effective, significantly increasing labile OC, SOC stock, and CMI by 35.3%, 140.5%, and 26% in the topsoil compared to the control and by 28%, 77.8%, and 4.3% compared to NPK alone. In the subsoil, mature cow dung-based treatments performed better. These findings highlight the potential of integrated organic and inorganic strategies, especially those based on composted manure, to rehabilitate degraded sodic soils, build carbon stocks, and improve soil quality for sustainable agriculture in coastal West Africa. Full article

Agricultural waste poses significant environmental, economic, and social challenges globally, with estimates indicating that 10–50% of agricultural products are discarded annually as waste. This review explores strategies for managing agricultural waste to mitigate its adverse impacts and promote sustainable development. Agricultural residues, such as those from sugarcane, rice, and wheat, contribute to pollution when improperly disposed of through burning or burying, contaminating soil, water, and air. However, these residues also represent untapped resources for bioenergy production, composting, mulching, and the creation of value-added products like biochar, bioplastics, single-cell protein and biobased building blocks. The paper highlights various solutions, including integrating agricultural waste into livestock feed formulations to reduce competition for human food crops, producing biofuels like ethanol and biodiesel from lignocellulosic materials, and adopting circular economy practices to upcycle waste into high-value products. Technologies such as anaerobic digestion for biogas production and gasification for synthesis gas offer renewable energy alternatives and ample feedstocks for gas fermentation while addressing waste management issues. Composting and vermicomposting enhance soil fertility, while mulching improves moisture retention and reduces erosion. Moreover, the review emphasizes the importance of policy frameworks, public-private partnerships, and farmer education in promoting effective waste management practices. By implementing these strategies, agricultural waste can be transformed into a resource, contributing to food security, environmental conservation, and economic growth. Full article

Phytoremediation strategies present promising approaches for mitigating metal contamination in soils. This study examines the effectiveness of compost and biochar amendments, applied separately or in combination, in altering the properties of sandy mining waste soils (Sw) and affecting levels of metallic trace elements (MTEs). The research evaluates changes in soil physicochemical parameters, metal concentrations in soil pore water (SPW), and metal accumulation in Phaseolus vulgaris. Compost and biochar addition significantly affected SPW pH, which remained alkaline, while increasing SPW electrical conductivity (EC). A treatment combining 20% compost and 2% biochar (SwC20B2) enhanced soil enzymatic activities, with the highest values observed for FDA and ALP activities. Metal availability in the SPW appeared higher on D(0) compared to D(12), with notable reductions in Pb and Zn concentrations observed in the SwC20B2 treatment. Despite this decline, metal accumulation in plant shoots did not significantly differ from that in plants grown in unamended Sw, although all plants exhibited substantial growth. The minor decrease in SPW pH, likely due to compost, may have enhanced metal mobility at D(0). Notably, SPW Pb and Zn concentrations increased with higher compost rates, with SwC20B2 registering the highest Pb and Zn. Although these amendments did not directly alleviate metal mobility, they show potential for use in phytostabilization strategies by using suitable plant species. Full article

Water hyacinth (Eichhornia crassipes) is a globally invasive aquatic weed with high biomass productivity and nutrient content, offering potential as a low-cost organic soil amendment. This review synthesizes findings from 35 studies identified through a structured Web of Science search, examining its use as mulch, compost, biochar, and foliar extract. Reported agronomic benefits include improvements in soil organic carbon, nutrient availability (particularly nitrogen and potassium), microbial activity, and crop yields. However, most studies are short-term and conducted under greenhouse or pot conditions, limiting field-scale generalizability. Additionally, reporting of compost composition and contaminant levels is inconsistent, raising concerns about food safety. While logistical and economic feasibility remain underexplored, emerging evidence suggests that with proper processing, water hyacinth amendments could reduce fertilizer dependence and contribute to circular bioeconomy goals. Future research should prioritize field trials, standardized production protocols, and life cycle assessments to evaluate long-term performance, risks, and climate benefits. Full article

Phosphorus is essential for crop growth, but excessive use of chemical fertilizers can lead to environmental issues. The incorporation of organic materials has the potential to enhance phosphorus availability and promote soil phosphorus cycling. This study investigated the effects of chemical fertilizer co-application with two organic materials on soil properties and functions. Four treatments were established: (1) chemical fertilizer alone (SC, consisting of urea, ammonium phosphate, and potassium sulfate), (2) chemical fertilizer with corn-straw-derived biochar (SCB), (3) chemical fertilizer with composted manure-based organic fertilizer (SCF), and (4) chemical fertilizer with both biochar and organic fertilizer (SCBF). This study focused on changes in soil properties, bioavailable phosphorus, phosphorus cycling functional genes, and related microbial communities. Compared to SC, the combined application of organic materials significantly increased available phosphorus (AP), alkaline hydrolysis nitrogen (AN), and available potassium (AK), with the SCBF exhibiting the highest increases of 78.76%, 47.47%, and 336.61%, respectively. However, applying organic materials reduced alkaline phosphatase (ALP) and acid phosphatase (ACP) activities, except for the increase in ACP in SCBF. Additionally, bioavailable phosphorus increased by up to 157.00% in SCBF. Adding organic materials significantly decreased organic phosphorus mineralization genes (phoA, phoD, phnP) and phosphate degradation genes (ppk2), while increasing inorganic phosphorus solubilization genes (pqqC, gcd), which subsequently increased CaCl₂-P and Citrate-P contents in SCB and in SCBF. In summary, organic material application significantly enhances phosphorus bioavailability by improving soil physicochemical properties and phosphorus-related gene abundance. These findings provide new insights into sustainable soil fertility management and highlight the potential of integrating organic materials with chemical fertilizers to improve soil nutrient availability, thereby contributing to increased soybean yield. Moreover, this study advances our understanding of the underlying mechanisms driving phosphorus cycling under combined fertilization strategies, offering a scientific basis for optimizing fertilization practices in agroecosystems. Full article

Straw biochar and compost can mitigate soil acidity and enhance carbon sequestration in acidic soils. However, their differential synergistic effects and underlying mechanisms remain poorly understood. To address this gap, an incubation experiment was conducted in which rice straw biochar (BC) and compost (DC) were incorporated into an Ultisol at rates of 1% and 3%. BC outperformed DC in elevating the soil pH (0.39 vs. 0.28 units), reducing the exchangeable acidity (69% vs. 62%), and decreasing the potential active aluminum pool (35.1% vs. 25.2%) due to its higher alkalinity. Additionally, BC enhanced the soil organic carbon more effectively than DC (83.7% vs. 64.0%). While 3% BC treatment reduced the readily oxidizable and dissolved organic carbon in the soil, DC increased these parameters. This contrasting effect is attributed to BC’s lower carbon reactivity, higher alkalinity, and greater C/N ratio compared to DC. Compared with the control, BC and DC also increased the soil exchangeable K⁺ (14.0-fold vs. 12.3-fold), Ca²⁺ (5.4-fold vs. 4.9-fold), and Mg²⁺ (3.7-fold vs. 5.2-fold). Overall, BC demonstrated superiority in mitigating acidity and sequestering carbon, while DC showed greater potential for improving fertility in acidic soils. Elucidating the distinct benefits of biochar versus compost provides valuable insights into the sustainable amelioration of acidic soils. Full article

This study evaluated the phytoremediation of mine tailing-contaminated soils in Quiulacocha, Peru, using the combined application of biochar and compost, with Zea mays L. (maize) serving as the phytoremediator due to its high biomass production and stress tolerance. A factorial experimental design was implemented, varying two main factors: the mining tailings dose (30% and 60% w/w) and the biochar pyrolysis temperature (300 °C and 500 °C). The mine tailings were characterized by high concentrations of heavy metals and unfavourable physico-chemical properties (pH, low organic matter), whereas the biochar, produced from pine forest residues, and the compost, derived from urban organic waste, exhibited attributes that enhance soil quality. During the pot experiment, response variables including the Bioconcentration Factor (BCF) and Translocation Factor (TF) for various metals were evaluated to assess the capacity for contaminant immobilization and their distribution between plant roots and aerial tissues. The results demonstrated that the incorporation of biochar and compost significantly improved soil quality by increasing pH, cation exchange capacity, and nutrient retention, while simultaneously reducing the bioavailability of heavy metals and limiting their translocation to the aerial parts of maize. Factorial analysis further indicated that both the tailings dose and biochar pyrolysis temperature significantly influenced the efficacy of the phytoremediation process. In conclusion, the combined application of biochar and compost presents an effective and sustainable strategy for rehabilitating mine tailing-contaminated soils by stabilizing heavy metals and promoting the safe growth of Zea mays L. Full article

Acid mine drainage (AMD) is a major environmental issue due to its high heavy metal concentrations and low pH, posing risks to ecosystems and human health. In Hualgayoc, Cajamarca, Peru, AMD contamination from mining activities necessitates effective remediation strategies. This study evaluated the removal efficiency of organic amendments, municipal waste compost (MWC), cattle manure compost (CMC), vermicompost (HMS), corn stalk biochar (CSB), sludge biochar (SLB), pine biochar (PBC), and native macrophytes Carex pichinchensis (CAX), Juncus ecuadoriensis (JSP), and Myriophyllum aquaticum (MYA) in removing As, Cd, Cu, Fe, and Zn. A physicochemical characterization of AMD, amendments, and plants was conducted, and sorption capacity was determined through triplicate analyses. The results showed that SLB achieved a 100% Zn removal, while CSB removed over 90% of Cu and Fe. Among the organic amendments, CMC demonstrated the highest As and Cd removal (~100%). Regarding macrophytes, CAX achieved a ~97% Fe removal, and MYA exhibited Cd affinity. CSB had the highest sorption capacity for Cu (0.139 mg/g), Fe (1.942 mg/g), and Zn (0.149 mg/g), highlighting its potential for metal remediation. Organic amendments enhanced metal adsorption and stabilization, outperforming macrophytes in heavy metal removal. Combining organic amendments with native plants is recommended to assess their synergistic potential for AMD remediation. Full article

Rock dust (RD) is a by-product of the precious metal mining industry. Some mining operations produce close to 2,000,000 Mg of RD/year, posing disposal issues. This study evaluated the physicochemical and microbial properties of RD from gold mining and its potential use in RD-based growing media. Ten media formulations were tested: Promix (Control), 100% (RD), 100% topsoil (TS), 50% RD + 50% topsoil (RDT), 25% RD + 75% topsoil (RT), 50% RD + 50% Promix (RP), 50% RD + 25% biochar + 25% Promix (RBP), 50% RD + 25% compost + 25% Promix (RCP), 50% RD + 50% biochar (RB), and Huplaso (negative control). RD particle size ranged from 0.1 to 2 mm with a bulk density of 1.5 g cm⁻³, while RD-based media ranged from 0.8 to 1.1 g cm⁻³ showing increased porosity. Nutrient content was analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), and the active microbial community assessed using PLFA biomarkers via GC-MS/FID, n = 4 and p = 0.05. Microbial analysis identified five classes (protozoa, eukaryotes, Gram-positive (G+), Gram-negative (G−), and fungi (F)), with a significant increase in G−, G+, and F in RD-based amendment RBP (28%) compared to control P (9%). G+, G−, and F showed a strong negative correlation (r = −0.98) with pH, while calcium correlated positively (r = 0.85) with eukaryotes and a strong positive correlation (r = 0.95) of cation exchange capacity with G+. This study suggests blending RD with organic amendments improves physicochemical quality and microbial activity, supporting its use in crop production over disposal. Full article