Potential Amendment Research Articles

Bioconversion of coir ETP sludge: An eco-friendly path to circular economy

The accumulation of sludge from Effluent Treatment Plants (ETPs) in coir industries has become a serious concern, raising critical questions about the eco-friendly management of large volumes of coir industry ETP sludge in coir-producing countries like India. This study aimed to explore a viable solution for bioprocessing the sludge and assess its potential as a soil amendment. Based on the C: N ratio and the initial characteristics of the ETP sludge, cow dung, and poultry manure were identified as potential amendments for sustainable bioconversion. The mixture was inoculated with TNAU Biomineralizer, a specialized culture that aids in decomposition. The bioconversion experiment used six treatment combinations (T1 to T6) to monitor nutrient transformations. Compost from treatment T6 (50% Sludge + 25% Poultry Manure + 25% Cow Dung + TNAU Biomineralizer) exhibited a significant improvement in nutrient content. The efficacy of the composted sludge was further assessed through a pot culture experiment using the Amaranthus variety CO 6, where different proportions of the composted sludge were applied alongside recommended agricultural practices. The results revealed that treatment T8 (100% Composted Sludge + Silica Solubilizing Bacteria) and the recommended package of practices combined with 100% Composted sludge significantly enhanced growth parameters, including root length, shoot length, and the number of leaves, outperforming other treatments. This study highlights that the bioconversion of coir industry ETP sludge with organic amendments and TNAU Biomineralizer offers a sustainable and eco-friendly solution, presenting a promising approach to advancing the circular economy.

ИСТОРИЧЕСКИЙ ОПЫТ И ТРАДИЦИИ РОССИЙСКОГО УГОЛОВНОГО ПРАВОСУДИЯ

Introduction: the article considers the historical experience and the current state of legal regulation of domestic criminal proceedings in the context of the influence on its reformation of national-historical traditions, mentalities and social expectations of the Russian people. It puts forward suggestions for improvements to the Criminal Procedure Code of the Russian Federation. Materials and Methods: the study employed a range of methods, including dialectical-materialistic, logical, historical, and historical-comparative approaches. Results: the analysis provided proposals for potential amendments to the Code of Criminal Procedure of the Russian Federation. Discussion and Conclusions: the proposed legislative changes are designed to reinforce the adversarial principles, humanity, and fairness of domestic criminal proceedings.

A Comparative Study of Biochar Derived from Two Different Sources and Inorganic NPK Fertilizer on the Growth and Biomass Yield of Wheat (Triticum aestivum L.)

Biochar has been regarding as a potential soil amendment for sustainable soil health, crop growth and mitigating climate change. Thus, the present study was performed to assess the effects of different rates of two biochar amendments and inorganic NPK fertilizer on the growth and biomass yield of wheat under pot condition at Chittagong University, Bangladesh. The two biochars prepared from mustard oil cake and rice straw by slow pyrolysis technique at 350-450 ºC were applied separately to the pot soil at the rate of 0, 1, 2, 3, 4 and 5% (w/w) and inorganic NPK fertilizer were also separately applied to the soil at the rate of 0, ¼, ½, ¾ and 1 of the recommended rate. The amended pot soil was incubated for 2 weeks before sowing of wheat seeds and observed the initial changes of soil properties. After 2 weeks of equilibration, soil organic carbon (OC) and Olsen P were relatively higher increased with oil cake biochar (OCB) whereas soil pH, electrical conductivity (EC) and available K were shown relatively higher value with rice straw biochar (RSB). The growth parameters at different growth periods and biomass yield after harvest were recorded. The growth parameters such as plant height, leaf number, spike growth, root length, total fresh and dry biomass were increased significantly (p < 0.05) with different rates of biochar and fertilizer amendments. In biochar amendment, the highest total fresh biomass (50.77 g.pot-1), total dry biomass (32.27 g.pot-1) and above ground dry biomass (27.14 g.pot-1) were found with 5% OCB rate which were statistically identical with 1 NPK rate (p < 0.05). Overall, the growth performance and biomass yield with OCB amendment was relatively better than RSB amendment. Our results suggest that both biochar (OCB or RSB) could be used to improve soils properties and hence productivity. Chittagong Univ. J. B. Sci. Vol. 12 (1 & 2): 56-71, 2024

Potential organic amendments for improving productivity and associated biological properties of low carbon soil

ABSTRACT Applying organic amendments with high carbon (C) content can indeed improve soil quality and increase crop yields. The objective of this 4-year field study was to evaluate the effects of three fertilizer-N application (N0, N75, and N100) levels in main plots and five levels of organic amendments incorporation (farmyard manure, poultry manure, press mud, rice straw compost and no manure) in wheat in sub-plots on soil biological properties, and crop yields in a low C sandy loam (Typic Ustochrept) soil. The application of fertilizer-N and organic amendments significantly increased all the soil enzyme activities as compared to the control. In contrast, the results of microbial biomass carbon, phenoloxidase, and peroxidase activity were significantly higher in farmyard manure treated plots by 64.6, 46.2 and 17.7%, respectively than control. Principal component analysis (PCA) suggests that dehydrogenase, xylanase, phenol oxidase, peroxidase and alkaline phosphatase can serve as sensitive indicators and were contribution to soil quality index by 42.5%, 11.3%, 46.8%, 22.6%, and 3.7%, respectively. Results suggest that locally available organic manures can be potential soil amendments to improve biological properties and enhance crop productivity under integrated nutrients management practices in rice-wheat cropping systems.

Potential amendments of coal fly ash-derived zeolite to beryllium contaminated soil at a legacy waste disposal site

Management of Be contamination using industrial solid waste or solid waste-derived amendments is not well understood. This study investigated the potential of Australian coal fly ash (CFA), derived synthesized zeolite (SynZ) and chitosan-modified zeolite (ModZ), for Be immobilization at the Little Forest Legacy Waste Site (LFLS), a low-level radioactive waste disposal site near Sydney, Australia. In laboratory simulation experiments, the SynZ and ModZ were separately applied as an amendment to both naturally contaminated soil and simulated contaminated (spiked) soil. Different techniques, including pore water (PW), batch desorption, and microbial activities were assessed to provide insight into immobilization mechanisms. Results revealed that amendment of 2% ModZ in soils, substantially decreased Be concentrations in PW (PWBe) ranging from 13.3% to 99.5% across all concentrations of Be. In contrast, PWBe increased while using SynZ, which could be attributed to the increased solubility of different organic-inorganic elements in PW. Moreover, batch desorption using Milli-Q water, simulated acid rainwater [H2SO4/HNO3 = 60/40, (v/v), and 0.11 M acetic acid solution also revealed similar patterns of Be immobilization as found in PWBe analysis. Soil amendments boosted microbial biomass carbon, and phosphorous (MBC,P), along with basal respiration (BRCO2). This indicates increased microbial activities, which are linked with environmental eco-friendliness. This effect was substantially noticed in ModZ-amended soils, exhibiting up to 22 times higher in BRCO2 values compared to unamended soil. Additionally, reduced PWBe was correlated with soluble organic-inorganic elements, desorbed Be in the batch study, and soil MBc. The differences in behavior between SynZ and ModZ underline the importance of carefully studying the various potential amendment materials and the need to evaluate their performance before application in field situations. This study highlights ModZ's effectiveness in eco-friendly Be immobilization, underlining the role of organic functional groups in zeolite architecture, a key factor in controlling Be in soils.

Fe3O4/Mulberry Stem Biochar as a Potential Amendment for Highly Arsenic-Contaminated Paddy Soil Remediation.

Magnetite-loaded biochar has recently received attention owing to its ability to remove arsenic from contaminated soil. In this study, mulberry stem biochar (MBC) and Fe3O4-loaded mulberry stem biochar (Fe3O4@MBC) were produced and used in a 100-day incubation experiment to investigate their performance in the stabilization of arsenic in paddy soil severely polluted by the As (237.68 mg·kg-1) mechanism. Incubation experiments showed that Fe3O4@MBC was more effective in immobilizing As after incubation for 100 days. Moreover, adding Fe3O4@MBC facilitated the transformation of exchangeable heavy metals into organic-bound and residual forms, thereby reducing As available concentrations, mobility, and bioavailability in the soil, and elevating slightly the soil pH and dissolved organic carbon (DOC). The concentration of TCLP-extractable As (AsTCLP) in contaminated soil was reduced from 93.85 to 7.64 μg·L-1 within 10 d, below the safety limit for drinking water set by the World Health Organization (WHO). The characterization results of Fe3O4@MBC after incubation indicated that the mechanisms for As passivation are linked to redox reactions, complexation, electrostatic attraction, surface adsorption, and coprecipitation. Conclusively, Fe3O4@MBC is a promising amendment in highly As-contaminated soil and provides a theoretical reference in such polluted paddy soil remediation.

Bio-Based Innovation and the Global Patent System: Exploring the WIPO Treaty on Intellectual Property, Genetic Resources and Associated Traditional Knowledge

Abstract This opinion critically examines the 2024 WIPO Treaty on Intellectual Property, Genetic Resources and Associated Traditional Knowledge, a new instrument addressing the use of genetic resources (GR), and traditional knowledge associated with GR (ATK) in the global patent system. Given the Treaty’s position at the intersection of intellectual property and environmental law, this article discusses its history and negotiation in the first part, including the Treaty’s links to the Convention on Biological Diversity (CBD) and the Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS). It then discusses the concept of bio-based innovation and its role in the bioeconomy. Following this, the article assesses the Treaty’s contents, including its context and objectives, scope, the Patent Disclosure Requirement (PDR), sanctions and remedies for non-compliance with the PDR, information systems on GR and ATK, and its relationship with other international instruments. The article highlights the extensive diplomatic negotiations that shaped the final text and considers potential amendments that could be made during the Treaty’s review process. The Treaty is intended to improve the global patent system’s effectiveness, transparency, and quality concerning GR and ATK and to prevent Offices from granting patents erroneously. Its provisions present new challenges and complexities for stakeholders, and its long-term success will depend on ongoing international collaboration and engagement, both within and outside the Treaty’s framework, and ensuring equitable benefit-sharing from the use of GR and ATK as part of a global sustainable bioeconomy.

QUALITY EVALUATION OF BIOCHAR FROM DIFFERENT AGRICULTURAL BIOMASS

Biochar, one of the co products of pyrolysis unit , is a potential soil amendment that sequestrates large amount of carbon which helps in increasing the soil fertility. And also application of biochar to t he soil reduces compaction, increase water holding capacity, nutrient availability, enhance biological activity, increase crop yields and reduce nitrous oxide emissions. In this research, bhendi and brinjal stalks are used to produce biochar by using pyrolysis. The nutritive content in biochar is analysed by proximate and ultimate analysis. As the result of proximate analysis, the nutritive contents such as moisture content, ash content, fixed carbon and volatile matter has recorded higher in bhendi stalks whereas in ultimate analysis such as carbon, nitrogen, hydrogen and sulfur, brinjal stalks has recorded a higher value. As the result, applications of biochars of bhendi stalks and brinjal stalks will improves the soil nutritive content than the biomass application KEYWORDS: Biochar, bhendi, brinjal, proximate analysis, ultimate analysis, soil fertility.

EU's “three-in-seven” road haulage cabotage rule – Impact imbalances across member states and the geography

Road cabotage within the EU, as a share of domestic transport of goods, varies greatly across member states. This can partly be attributed to EU's regime for consecutive cabotage. In addition to economic factors that reflect incomplete market integration, spatial factors appear to affect the impact of the current regime. The impact seems stronger for geographically large and centrally located countries with interregional homogeneity in trade. This may reflect that foreign hauliers under such conditions can utilize the characteristics of their standardized long-range trucks better, or because the likelihood of successfully fixing three favourable long-distance cabotage assignments within the seven days limit increases. Potential amendments to regulations in order to equalize the impact of EU's consecutive cabotage regime across member states' spatial characteristics include removing the limits to the number of trips within the seven days' time frame or shortening the time frame for carrying out the current maximum of three trips.

Spectral induced polarization of corrosion of sulfur modified Iron in sediments

Spectral induced polarization (SIP) responses are not well understood within the context of remediation applications at contaminated sites. Systematic SIP studies are needed to gain further insights into the complex electrical response of dynamic, biogeochemical states to enable the use of SIP for subsurface site characterization and remediation monitoring. Although SIP measurements on zero valent iron have been previously published, the SIP response for sulfur modified iron (SMI), a similar potential subsurface reductive amendment, has not yet been reported. Hence, the purpose of this laboratory-scale study was to evaluate SIP for nonintrusive monitoring of SMI under relevant subsurface conditions. SMI was separately mixed with silica sand or sediments from the Hanford Site (Washington, USA) and then packed into columns for geochemical and SIP analysis for up to 77 days under fully saturated conditions. SMI exhibited distinguishable phase peaks between 0.1 and 1.0 Hz, which changed in magnitude based on content and were detected as low as 0.3 wt%. In the initial days, the complex conductivity, phase maxima, and chargeability increased while the peak locations shifted to higher frequency (decreasing relaxation times), suggesting an initial increase in polarization and concurrent decrease in the length scales (potentially due to changes in particle size and mineralogy). Then, after 77 days, the phase maxima and chargeability decreased with a concurrent increase in relaxation times, suggesting that over longer periods, less polarizable phases are forming and particle size or connectivity of polarizable phases is increasing. These results demonstrated a unique SIP response to SMI transformations that might be applied to monitoring of SMI emplaced as a subsurface barrier or injected in the field.

Cannabis Legalization in Canada and Combatting the Illicit Cannabis Market

Despite the elimination of the illegal cannabis market being a fundamental element to cannabis legalization, as outlined in the Cannabis Act (S.C. 2018, c. 16), the Canadian federal government's efforts have had a mild impact in mitigating its influence. In analyzing possible contributions to the illicit sector's sustainability, these factors are in large part due to the federal government failing to understand consumer behaviours in recreational cannabis usage, as evidenced by lack of accommodation for frequent users, pricing and quality of legal cannabis compared to illegal cannabis, alongside faulty enforcement of cannabis law due to issues of conciseness and discretionary powers between the police and federal government. However, there are some suggestions that could better help the federal government in achieving its goal of combatting the illegal cannabis market. The potential amendments to cannabis policy include lowering tax on legal cannabis to better compete with illegal cannabis at the market level while refocusing on addressing public health concerns through promoting the safety of legal cannabis, controlling accessibility of legal cannabis, and providing public education regarding cannabis consumption. If done correctly, each amendment made would address the flaws within cannabis policy, allowing the Canadian federal government to combat the illegal cannabis market more efficiently.

Influence of Hemp Residues on Soil Chemical Parameters and Spring Wheat Productivity

The utilization of hemp residues, obtained after the harvest of hemp flowers, is a potential soil amendment in crop cultivation that might enhance soil health, nutrient availability, and crop productivity. However, more research is required to choose the best agricultural practice for optimizing hemp residue degradations. This study aimed to determine the integrated effects of hemp residues in different soil tillage systems on spring wheat yield. The results of the two-year experiment show that under favorable climatic conditions and soil moisture contents, the highest spring wheat grain yield (6.0 t ha−1) is achieved in plots where hemp residues are plowed in autumn. Similar results are obtained in dry weather conditions, but the yield is lower by more than half—2.3 t ha−1. The influence of residues increases the C content in the soil. The findings advance our understanding of integrated agricultural practices through the utilization of hemp residues for promoting resilient and sustainable crop production systems.

Discarded substrates from soilless hydroponic horticulture as potential amendments for metal-contaminated soils

Soil contamination with metals is a major threat for the environment and public health since most metals are toxic to humans and to non-human biota, even at low concentrations. Thus, new sustainable remediation approaches are currently needed to immobilize metals in soils to decrease their mobility and bioavailability. In this work, we explore the application of discarded substrates from hydroponic cultivation, namely coconut shell and a mixture of coconut shell and pine bark, for immobilization of metals (Cd, Cr, Ni, Cu, Pb, Hg, Sb and As) in a naturally contaminated soil from a mining region in Portugal. The immobilization capacity of substrates (added to the soil at 5% mass ratio) was assessed both individually and also combined with other traditional agriculture soil additives (limestone and gypsum, at 2% mass ratio) and nanoparticles of zero-valent iron (nZVI) at 1–3% mass ratio. The overall results obtained after a 30-d incubation showed that the discarded substrates are a viable, economic, and environmental-friendly solution for metal remediation in soils, with the capacity of immobilization ranging from 20 to 91% for the metals and metalloids studied. Furthermore, they showed the capacity to reduce the soil toxicity (EC50 ∼ 6000 mg/L) to non-toxic levels (EC50 > 10000 mg/L) to the bacteria Aliivrio fischeri.

Insights into the ameliorative effect of ZnONPs on arsenic toxicity in soybean mediated by hormonal regulation, transporter modulation, and stress responsive genes.

Arsenic (As) contamination of agricultural soils poses a serious threat to crop productivity and food safety. Zinc oxide nanoparticles (ZnONPs) have emerged as a potential amendment for mitigating the adverse effects of As stress in plants. Soybean crop is mostly grown on marginalized land and is known for high accumulation of As in roots than others tissue. Therefore, this study aimed to elucidate the underlying mechanisms of ZnONPs in ameliorating arsenic toxicity in soybean. Our results demonstrated that ZnOB significantly improved the growth performance of soybean plants exposed to arsenic. This improvement was accompanied by a decrease (55%) in As accumulation and an increase in photosynthetic efficiency. ZnOB also modulated hormonal balance, with a significant increase in auxin (149%), abscisic acid (118%), gibberellin (160%) and jasmonic acid content (92%) under As(V) stress assuring that ZnONPs may enhance root growth and development by regulating hormonal signaling. We then conducted a transcriptomic analysis to understand further the molecular mechanisms underlying the NPs-induced As(V) tolerance. This analysis identified genes differentially expressed in response to ZnONPs supplementation, including those involved in auxin, abscisic acid, gibberellin, and jasmonic acid biosynthesis and signaling pathways. Weighted gene co-expression network analysis identified 37 potential hub genes encoding stress responders, transporters, and signal transducers across six modules potentially facilitated the efflux of arsenic from cells, reducing its toxicity. Our study provides valuable insights into the molecular mechanisms associated with metalloid tolerance in soybean and offers new avenues for improving As tolerance in contaminated soils.

From waste to resource: Assessing the feasibility of municipal sludge as a fertilizer from a soil and microbial perspective

Municipal sludge is rich in nutrients and microbial populations, making it a potential soil amendment to enhance fertility. This study aimed to investigate the impact of municipal sludge application on microbial populations and assess its suitability as a fertilizer. The results indicated a significant increase in organic matter content in sandy soil after municipal sludge application (from 9.57 to 23.62 mg·kg−1). Available potassium and phosphorus levels improved from poor to intermediate, and available nitrogen reached an excellent level. Plant parameters such as wet weight, diameter, root length, and aboveground height also showed improvement with municipal sludge addition. High-throughput sequencing revealed Shannon and Simpson indices exceeding 5.26 and 0.98, respectively, across all substrates except B1, indicating enhanced microbial community structure and diversity in sandy soil. Redundancy analysis highlighted the pivotal role of total phosphorus, available phosphorus, organic matter, available nitrogen, total nitrogen, and available potassium in enriching microbial abundance and diversity. In conclusion, using municipal sludge as fertilizer is feasible and beneficial for soil safety, fertility, and microbial populations enhancement.

Optimization of anaerobic soil disinfestation against Verticillium wilt in strawberry cultivation using local agrowastes as amendments.

The study explores anaerobic soil disinfection as an alternative to soil fumigants for controlling Verticillium wilt in strawberry crops. For this purpose, two agrowastes close to the strawberry-growing areas of Huelva province were tested as potential amendments for the control of Verticillium wilt: rice bran and residual strawberry extrudate. Furthermore, two application rates were evaluated: 13.50 and 20.00 t/ha for the rice bran and 16.89 and 25.02 t/ha for residual strawberry extrudate. Amended and anaerobically disinfested soils were compared with a non-amended soil under anaerobic conditions, a soil treated with the chemical fungicide metam sodium and an untreated soil. One week before the start of disinfection treatment, these soils were artificially inoculated with 250 microsclerotia/g dry soil of Verticillium dahliae. After disinfestation treatments, pathogens were quantified, and strawberry plants were cropped in a growth chamber to further evaluate Verticillium wilt severity, which was measured with a symptom scale in the same potting soils. Measurements of the anaerobic condition, pH and microbial population densities were performed, and the results showed significant differences between the different amendments. In addition, the treatment with rice bran at 20 t/ha recorded the lowest population density of V. dahliae. Likewise, it was possible to achieve a reduction in foliar disease severity in all amended treatments in similar percentage to those obtained by chemical treatment. These results suggest potential application of this technique for the control of Verticillium wilt in the strawberry-growing area of Huelva, reducing the use of chemical fumigants.

Household dog fecal composting: Current issues and future directions.

Dog feces are a known source of nutrient, pathogen, and plastic pollution that can harm human and ecosystem health. Home composting may be a more environmentally sustainable method of managing dog feces and reducing this pollution. While composting is an established method for recycling animal manures into low-risk soil conditioners for food production, few studies have investigated whether household-scale compost methods can safely and effectively process dog feces for use in backyard edible gardens. A broad range of literature on in situ composting of dog feces is evaluated and compared according to scale, parameters tested, and compost methods used. Studies are analyzed based on key identified knowledge gaps: appropriate compost technologies to produce quality soil conditioner on small scales, potential for fecal pathogen disinfection in mesophilic compost conditions, and biodegradation of compostable plastic dog waste bags in home compost systems. This review also discusses how existing methods and quality standards for commercial compost can be adapted to dog fecal home composting. Priorities for future research are investigation of household-scale aerobic compost methods and potential compost amendments needed to effectively decompose dog feces and compostable plastic dog waste bags to produce a good-quality, sanitized, beneficial soil conditioner for use in home gardens. Integr Environ Assess Manag 2024;20:1876-1891. © 2024 The Author(s). Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Mitigating microplastic stress on peanuts: The role of biochar-based synthetic community in the preservation of soil physicochemical properties and microbial diversity

Tire-derived rubber crumbs (RC), as a new type of microplastics (MPs), harms both the environment and human health. Excessive use of plastic, the decomposition of which generates microplastic particles, in current agricultural practices poses a significant threat to the sustainability of agricultural ecosystems, worldwide food security and human health. In this study, the application of biochar, a carbon-rich material, to soil was explored, especially in the evaluation of synthetic biochar-based community (SynCom) to alleviate RC-MP-induced stress on plant growth and soil physicochemical properties and soil microbial communities in peanuts. The results revealed that RC-MPs significantly reduced peanut shoot dry weight, root vigor, nodule quantity, plant enzyme activity, soil urease and dehydrogenase activity, as well as soil available potassium, and bacterial abundance. Moreover, the study led to the identification highly effective plant growth-promoting rhizobacteria (PGPR) from the peanut rhizosphere, which were then integrated into a SynCom and immobilized within biochar. Application of biochar-based SynCom in RC-MPs contaminated soil significantly increased peanut biomass, root vigor, nodule number, and antioxidant enzyme activity, alongside enhancing soil enzyme activity and rhizosphere bacterial abundance. Interestingly, under high-dose RC-MPs treatment, the relative abundance of rhizosphere bacteria decreased significantly, but their diversity increased significantly and exhibited distinct clustering phenomenon. In summary, the investigated biochar-based SynCom proved to be a potential soil amendment to mitigate the deleterious effects of RC-MPs on peanuts and preserve soil microbial functionality. This presents a promising solution to the challenges posed by contaminated soil, offering new avenues for remediation.

A biochar selection method for remediating heavy metal contaminated mine tailings

Approximately 390,000 abandoned mines across the US pose considerable, pervasive risks to human and environmental health; world-wide the problem is even greater. Lime, organic materials, and other amendments have been used to decrease metal bioavailability (e.g., Cd, Cu, Mn, Ni, Zn) in contaminated mine wastes and to promote plant community establishment for tailings stabilization. Biochar properties (e.g., alkaline pH, metal sorbing capabilities, available nutrients, improved soil water retention) make it a potential amendment for remediating metal contaminated mine tailings. A three-step procedure was developed to identify biochars that were most effective at reducing heavy metal availability, retaining metals, and subsequently selecting biochars for use in a soil amendment laboratory trial to ultimately be utilized in heavy metal contaminated mine land settings: Step (1) a synthetic precipitation leaching procedure extract of mine tailings was produced, representing potentially available metals, and used to identify metal removal properties of 28 different biochars (e.g., made from various feedstocks and pyrolysis or gasification conditions); Step (2) evaluate how well biochars retained previously sorbed metals; and Step (3) laboratory evaluation of the most promising biochars that removed and did not releases metals, applied at 0, 1, 2.5, and 5% (by wt) to mine tailings for reducing metal bioavailability. The reported methodology and results from this study could be used to quickly identify specific biochars and application rates to reduce mine tailings metal availability and aid in future remediation of abandoned mine sites globally.

Biochar aided priming of carbon and nutrient availability in three soil orders of India

In recent years biochar (BC) has gained importance for its huge carbon (C) sequestration potential and positive effects on various soil functions. However, there is a paucity of information on the long-term impact of BC on the priming effect and nutrient availability in soil with different properties. This study investigates the effects of BC prepared from rice husk (RBC4, RBC6), sugarcane bagasse (SBC4, SBC6) and mustard stalk (MBC4, MBC6) at 400 and 600 °C on soil C priming and nitrogen (N), phosphorus (P), and potassium (K) availability in an Alfisol, Inceptisol, and Mollisol. BC properties were analyzed, and its decomposition in three soil orders was studied for 290 days in an incubation experiment. Post-incubation, available N, P, and K in soil were estimated. CO2 evolution from BC and soil alone was also studied to determine the direction of priming effect on native soil C. Increasing pyrolysis temperature enhanced pH and EC of most of the BC. The pyrolysis temperature did not show clear trend with respect to priming effect and nutrient availability across feedstock and soil type. MBC6 increased C mineralization in all the soil orders while RBC6 in Alfisol and SBC6 in both Inceptisol and Mollisol demonstrated high negative priming, making them potential amendments for preserving native soil C. Most of the BC showed negative priming of native SOC in long run (290 days) but all these BC enhanced the available N, P, and K in soil. SBC4 enhanced N availability in Alfisol and Inceptisol, RBC4 improved N and P availability in Mollisol and P in Alfisol and MBC6 increased K availability in all the soils. Thus, based on management goals, tailored BC or blending different BC can efficiently improve C sequestration and boost soil fertility.