Waste Compost Research Articles

Diffusion of innovative soil management practices for sustainable vegetable farming

Vegetable farmers in Sokoto state, Nigeria are disadvantaged by problem soils that are generally low in nutrient content, leading to below optimum output. As a result, this research was undertaken to disseminate innovative soil management practices through participatory on-farm trials using household waste compost, vermicompost, and biochar as treatments toward ensuring sustainable vegetable farming. The research covered a sequence of 3 main activities; including baseline survey through focus group discussion (FGD), pre and post project soil sample analyses (0-15cm and 15-30cm depths) and trials, and dissemination of findings via result demonstration, respectively. Findings from the baseline revealed that, the vegetable farmers were vulnerable and never had contact with an extension worker, living below $50/month and confronted by dwindling vegetable output due to acidity and low nutrient content of the soil. Amaranth, cabbage, lettuce, tomatoes, peppers, onions, and carrot were the mainly cultivated vegetables by the farmers. Soil management practices in the research sites were occasional application of inorganic fertilizers and traditional application of municipal waste, crop residue and refuse, which was due to inadequate knowledge on sustainable management practices of the soil. Application of organic amendments including household waste compost, vermicompost, and biochar caused tremendous variation in post-project soil properties (EC, K, Na, Ca, Mg, CEC, N, OC and P). Similarly, yield and benefit cost ratio of the trial crop (amaranth) significantly improved due to the amendments. Hence, application of organic soil amendments especially household waste and biochar would be worthwhile for sustainability of vegetable farming in Sokoto state, Nigeria.

Health Risk Assessment for Potentially Toxic Elements Accumulation in Amaranthaceae Family Cultivars and their Correlation with Antioxidants and Antinutrients.

Delhi's agricultural hub, nestled along the Yamuna floodplains, faces soil and water contamination issues. Utilizing organic waste composts is gaining traction to improve soil quality, but uncertainties remain about their efficacy in reducing harmful elements. The study examined three Amaranthaceae cultivars, comparing organic waste composts with chemical fertilizer to evaluate correlations between heavy metals, antioxidants, and antinutrients to assess their bioremediation potential. "Heavy metals" or "potentially toxic elements (PTE)" levels in soil and leaves were measured by ICP-MS, while antioxidants and antinutrients were analyzed with UV-VIS spectroscopy. The study revealed higher PTE levels in floodplain soil, with Cr, Ni, and Cd exceeding safe limits in all cultivars. Compost amendments reduced these pollutants by 28% compared to chemical fertilizers, decreasing bioaccumulation by 20%. Health risk assessments showed lower risks in compost-amended cultivars. Additionally, compost amendment displayed a stronger negative correlation between PTE and antioxidants, suggesting effective bioremediation. Overall, compost amendments offer promise for mitigating PTE in metropolitan floodplains.

Impacts of Compost Amendment Type and Application Frequency on a Fire-Impacted Grassland Ecosystem

Composting organic matter can lower the global warming potential of food and agricultural waste and provide a nutrient-rich soil amendment. Compost applications generally increase net primary production (NPP) and soil water-holding capacity and may stimulate soil carbon (C) sequestration. Questions remain regarding the effects of compost nitrogen (N) concentrations and application rates on soil C and greenhouse gas dynamics. In this study, we explored the effects of compost with different initial N quality (food waste versus green waste compost) on soil greenhouse gas fluxes, aboveground biomass, and soil C and N pools in a fire-impacted annual grassland ecosystem. Composts were applied annually once, twice, or three times prior to the onset of the winter rainy season. A low-intensity fire event after the first growing season also allowed us to explore how compost-amended grasslands respond to burning events, which are expected to increase with climate change. After four growing seasons, all compost treatments significantly increased soil C pools from 9.5 ± 0.9 to 30.2 ± 0.7 Mg C ha−1 (0–40 cm) and 19.5 ± 0.9 to 40.1 ± 0.7 Mg C ha−1 (0–40 cm) relative to burned and unburned controls, respectively. Gains exceeded the compost-C applied, representing newly fixed C. The higher N food waste compost treatments yielded more cumulative soil C (5.2–10.9 Mg C ha−1) and aboveground biomass (0.19–0.66 Mg C ha−1) than the lower N green waste compost treatments, suggesting greater N inputs further increased soil stocks. The three-time green waste application increased soil C and N stocks relative to a single application of either compost. There was minimal impact on net ecosystem greenhouse gas emissions. Aboveground biomass accumulation was higher in all compost treatments relative to controls, likely due to increased water-holding capacity and N availability. Results show that higher N compost resulted in larger C gains with little offset from greenhouse gas emissions and that compost amendments may help mediate effects of low-intensity fire by increasing fertility and water-holding capacity.

Hyperthermophilic composting of livestock waste drastically reduces antimicrobial resistance

Composting is the most common method for managing livestock waste. However, it often fails to effectively eliminate antimicrobial resistance, resulting in potential antimicrobial resistance in livestock waste. Hence, a more effective livestock waste management strategy is warranted. The hyperthermophilic composting method uses recycled compost containing hyperthermophilic microbes to raise the compost temperature up to approximately 100 °C (compost temperature in normal composting: 50–70 °C). This study clarifies the effectiveness of hyperthermophilic composting method in attenuating antimicrobial resistance during livestock waste composting in both a composting simulator and on a field dairy farm. We analyzed bacterial abundance and community composition, performed PCR analysis, and evaluated the concentration of residual antimicrobials in the compost. Hyperthermophilic composting significantly reduced the abundance of culturable bacteria and Escherichia coli including that of antimicrobial-resistant culturable bacteria and E. coli in both the simulated and field dairy farms. The copy numbers of the tested antimicrobial resistance genes (tetA, tetB, blaTEM, and blaCTX-M) decreased substantially. Residual antimicrobials (tetracyclines and β-lactams) were not detected in the field dairy farms, and network analysis showed that potential hosts of antimicrobial-resistance genes were eliminated. These results indicate that hyperthermophilic composting significantly reduces the abundance of antimicrobial-resistant bacteria, antimicrobial-resistance genes, and residual antimicrobials at low cost and easy operation while generating valuable agricultural resource as the final output.

Effects of woodchip biochar on temperature sensitivity of greenhouse gas emissions in amended soils within a mountain vineyard

The utilization of biochar as a soil amendment holds promise for long-term carbon sequestration due to its elevated carbon content and persistent chemical structure. This characteristic has positioned biochar as a proposed nature-based solution for climate change mitigation. Nevertheless, the impact of biochar on soil greenhouse gas (GHG) emissions remains a subject of ongoing debate. In the present investigation, we evaluated the influence of conifer wood biochar on the fluxes of three GHGs, namely carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4), in a vineyard soil subjected to biochar-alone treatments (at rates of 25 and 50 t ha−1) and in combination with green waste compost (at a rate of 45 t ha−1). The experimental field was situated in northern Italy and was organized in a randomized block design. Soil GHG fluxes were monitored for two and a half years. Monthly flux measurements were conducted using a high-resolution multi-gas analyzer for 24 hours. Fluxes were, therefore, correlated with soil temperature to assess the influence of treatments on the sensitivity of GHG emissions to this pivotal environmental parameter. The findings demonstrated diminished temperature sensitivity in the initial experimental year across all GHG fluxes in soils amended with biochar and biochar-compost combination, in contrast to treatments lacking biochar (i.e., control and compost-alone treatments). Notably, the attenuation was most pronounced for N2O emissions, suggesting a potential role of biochar in mitigating the release of this gas. However, this effect did not persist in the second and third years of the experiment. Overall, biochar significantly contributed to a reduction in N2O fluxes and an increase in CO2 fluxes, but the effect was limited and temporary. Furthermore, biochar had no impact on CH4 fluxes. The discerned fluctuation in the impact of biochar over time can be attributed to the processes of biochar aging and/or the interannual variability in soil moisture.

Techno-economic assessment of industrial food waste composting facility: Evaluating bulking agents, processing strategies, and market dynamics

Techno-economic assessment (TEA) of a valorization of bulking agent (BA) ratios on the food waste compost value chain is made to assess economic feasibility. TEA was performed with two plans (Plan A: existing composting facilities; Plan B: new composting facilities) and each plan was under four scenarios. The BA (i.e. corn stalks, garden waste, and watermelon seedlings) ratio of 5 % (S1), 10 % (S2), 20 % (S3), and garden waste with a ratio of 20 % (S4). Results indicate that S2, with a net present value (NPV) of 128.9 million, represents Plan A’s most economically viable scenario. Although the total operating costs of S4 were 18.9 %–23.5 % higher, 25.6 %–42.2 % higher total revenue made S4 have an NPV of 92.9 million, making it the most viable scenario in Plan B. All scenarios show positive NPV within a ± 20 % fluctuation range. Organic fertilizer price, government subsidies, and processing capacity were the key factors influencing NPV.

Assessment of climate change impact and resource-use efficiency of lettuce production in vertical farming and greenhouse production in Finland: a case study

PurposeOur aim in this study was to examine lettuce production in vertical farming or in conventional greenhouse production in Northern European conditions from the perspective of climate change impact and environmental sustainability. Further, the goal was to identify practices and choices that could mitigate adverse effects and increase resource-use efficiency, allowing the development of more sustainable production systems.MethodsThis article provides new information of the environmental impacts of lettuce production in greenhouses and vertical farming in Finland, compared using the life cycle assessment (LCA) methodology. The impact categories used were climate change impact, cumulative energy demand, resource use of fossil energy sources, resource use of minerals and metals, land use, and water scarcity. The system boundaries covered the production chains from cradle to farmgate, including inputs in production, as well as direct emissions caused by fertiliser use and the onsite composting of organic waste. The environmental impacts of the two production systems with different energy scenarios were assessed: (1) a greenhouse either with average or renewable energy; and (2) vertical farming either with average or renewable energy and with or without waste heat recovery. The data for vertical farming were based on one Finnish production site and supplementary data for the construction materials. The greenhouse data were based on a previous LCA investigation of average Finnish lettuce production.ResultsThe climate change and all other impact categories were lowest for lettuce produced in vertical farming with renewable energy and waste heat recovery. The climate change impact was largest for lettuce produced in greenhouse with average energy use. For energy use and energy resource use, the impacts of vertical farming were lower than greenhouse production, but for mineral and metal use and water scarcity, the impact of vertical farming was higher for average energy use without heat recovery. Direct land and irrigation water use on the production sites in Finnish circumstances represented only a small share of total land-use and water-use impacts on both production methods.ConclusionPaying attention to the energy source and heat recovery, the environmental sustainability can be advanced in both vertical and greenhouse production systems.

Microbial electrochemical enhanced composting of sludge and kitchen waste: Electricity generation, composting efficiency and health risk assessment for land use

To realize the energy and resource utilization from organic solid waste, a two-phase microbial desalination cell (TPMDC) was constructed using dewatered sludge and kitchen waste as the anode substrate. The performance of electricity generation and composting efficacy was investigated, along with a comprehensive assessment of the potential health risks associated with the land use of the resulting mixed compost products. Experimental outcomes revealed a maximum open-circuit voltage of 0.893 ± 0.005 V and a maximum volumetric power density of 0.797 ± 0.009 W/m³. After 90 days of composting enhanced by microbial electrochemistry, a significant organic matter removal rate of 31.13 ± 0.44 % was obtained, and the anode substrate electric conductivity was reduced by 30.02 ± 0.04 % based on the anode desalination. Simultaneously, there was an increase in the content of available nitrogen, phosphorus, and potassium, as well as an improvement in the seed germination index. The forms of heavy metals shifted from bioavailable to stable residual states. The non-carcinogenic hazard index (HI) values for heavy metals and polycyclic aromatic hydrocarbons (PAHs) during the land use of compost products were less than 1, and the total carcinogenic risk (TCR) values for heavy metals and PAHs were below the acceptable threshold of 10−4. The occupational population risk of infection from five pathogens was higher than that of the general public, with all risk values ranging from 8.67 × 10−8 to 1, where the highest risk was attributed to occupational exposure to Legionella. These outcomes demonstrated that the mixture of dewatered sludge and kitchen waste was an appropriate anode substrate to enhance TPMDC stability for electricity generation, and its compost products have promising land use suitability and acceptable land use risk, which will provide important guidance for the safe treatment and disposal of organic solid waste.

Performance of Effective Microorganism (EM) in Food Waste Composting and Their Association with Seed Germination on Kale Seed

Food waste has an influence throughout the whole food supply chain, from production to consumption. Composting effectively and affordably reduces the need for synthetic fertilizers, water, soil erosion, pesticides, and soil carbon storage. Composting may also improve crop yields and soil fertility, leading to more sustainable farming practices. The potential of efficient microorganisms (EM) for dehydrated food waste decomposition was investigated in this study. The research assessed the temperature and pH profiles during composting, whereas nitrogen, phosphorus, potassium, organic content, and E. coli were measured in mature composts. Therefore, the study revealed that EM greatly hastened the composting process by boosting critical factors such as temperature, pH, nitrogen content (TN : 1.17±0.6%, TP: 0.059±1.92%, K: 0.12±5.3%) organic enrichment (85%), and E-coli (<1 MPN/g). The germination index (GI) of kale seed was then analysed with the study’s findings indicating an 80% soil-compost ratio was the best. This research investigates the use of effective microorganisms (EM) to transform food waste into beneficial agricultural resources, with favourable results for soil health and kale seed germination. Researchers and circular economy officials may use the results to promote sustainable agriculture. The research helps to minimize landfill food waste, methane emissions, and synthetic fertilizer consumption, all of which benefit the environment. Farmers and gardeners may use the findings to boost soil fertility and crop yields on a budget. This research indicates that food waste may be transformed into useful resources, encouraging sustainable and eco-friendly agricultural.

Efficacy of various amendments for immobilization of potentially toxic elements in wastewater contaminated soils

Farmers are using municipal wastewater either treated or untreated for irrigation because of limited fresh water resources. Wastewater extensively used for irrigation purposes is enriched with many nutrients. The reuse of wastewater is imposing a negative impact on human health and the ecosystem. It is a need of the day to identify and assess issues of the reuse of wastewater. In the current experiment, impact of organic/inorganic amendments was studied to mitigate the toxic effects of pollutants present in wastewater. Soil was brought from the site having consistent use of wastewater and different treatments were applied as per plan. The experiment has 28 treatments with 04 replications. Nine different amendments were used at 3 varying levels. Incubation time of 30 days was given after the addition of all treatments. The results of the study showed the application of FYM @ 5.0% w/w soil reduced soil pH (7.44), EC (2.16 dS m−1), SAR (8.14), lead (8.48 mg kg−1), cadmium (1.14 mg kg−1), nickel (10.55 mg kg−1) and arsenic (2.03 mg kg−1) when compared with control and other treatments. Usage of compost and horse waste followed FYM. On the basis of this study, it is recommended that wastewater can be used for irrigation purpose after treating with FYM preferably and compost in general.

Organic Fraction Municipal Solid Waste Compost and Horse Bean Green Manure Improve Sustainability of a Top-Quality Tobacco Cropping System: The Beneficial Effects on Soil and Plants

Organic Fraction Municipal Solid Waste Compost and Horse Bean Green Manure Improve Sustainability of a Top-Quality Tobacco Cropping System: The Beneficial Effects on Soil and Plants

The Potential of Agricultural Waste Compost to Elevate Growth and Rice Production with the SRI Method in Acid Sulfate Soils

The Potential of Agricultural Waste Compost to Elevate Growth and Rice Production with the SRI Method in Acid Sulfate Soils

Design, Technical Development, and Evaluation of an Autonomous Compost Turner: An Approach towards Smart Composting

In a sustainable circular economy, the composting of organic waste plays an essential role. This paper presents the design and technical development of a smart and self-driving compost turner. The architecture of the hardware, including the sensor setup, navigation module, and control module, is presented. Furthermore, the methodological development using model-based systems engineering of the architecture of concepts, models, and their subsequent software integration in ROS is discussed. The validation and verification of the overall system are carried out in an industrial environment using three scenarios. The capabilities of the compost turner are demonstrated by requiring it to autonomously follow pre-defined trajectories at the composting plant and perform required composting tasks. The results prove that the autonomous compost turner can perform the required activities. In addition to autonomous driving, the compost turner is capable of intelligent processing of the compost data and of transferring, visualizing, and storing them in a cloud server. The overall system of the intelligent, autonomous compost turner can provide essential leverage for improving sustainability efforts, thus contributing substantially to an environmentally friendly and sustainable future.

Temporal trends of polycyclic aromatic hydrocarbons in soils amended with sludge, compost, and manure in a Scotland pasture: An 8-year field experiment

To optimize the effective utilization of organic waste in agricultural practices, a comprehensive assessment of associated risks and benefits is crucial. This study investigated the impact of three types of organic wastes (sludge, compost, and manure) on polycyclic aromatic hydrocarbons (PAHs) in contaminated soil in a Scottish pasture. The experimental setup comprised 16 plots with four treatments (compost, manure, sludge, and inorganic fertilizer) and four replicates. After eight years of this study, notable disparities in ΣPAH16 concentrations were observed among the different treatments, with compost-amended soil at 378 μg kg−1, sludge-amended soil at 331 μg kg−1, and manure-amended soil at 223 μg kg−1. The concentrations of ΣPAH16 in soil amended with compost and sludge exhibited a linear increase with extended sampling time. Significant changes in ΣPAH16 concentration were evident in the compost treatment plot, with an increase of 20% in the first year and 82% in the eighth year. Risk assessment suggested a low level of health risk from exposure to PAHs at the measured concentrations in the three organic wastes. In conclusion, this study highlights the importance of considering the effects of organic waste amendments on soil PAH levels to make informed decisions in sustainable agricultural practices. It also underscores the need for ongoing research to fully understand the implications of different organic waste applications on soil health and environmental quality.

Photosynthetic Activities, Phytohormones, and Secondary Metabolites Induction in Plants by Prevailing Compost Residue.

Compost residue enriches soil health with the potential to enhance plant metabolism and hormonal balance, but has not yet been studied. A study was performed to determine how prevailing compost residue induces tomato (Solanum lycopersicum 'Scotia') plant morpho-physiology, phytohormones, and secondary metabolites. Plants were grown in soils with a previous history of annual (AN) and biennial (BI) compost amendments. The controls were soil without compost (C) amendment and municipal solid waste compost (MSWC) alone. The MSWC- and AN-plants had similar and significantly (p < 0.05) highest growth and photosynthetic activities compared to the BI- or C-plants. Total phenolics and lipid peroxidase activity were significantly (p < 0.001) high in BI-plants, while hydrogen peroxide and antioxidant capacity were significantly (p < 0.001) high in AN-plants. MSWC-plants recorded the highest cis-abscisic acid, followed by AN-, and then BI- and C-plants. Cis-zeatin, trans-zeatin, and isopentenyladenine ribosides were detected in the MSWC- and AN-plants but not in the BI- or C-plants. Furthermore, gibberellins GA53, GA19, and GA8 were high in the MSWC-plants, but only GA8 was detected in the AN plants and none in the others. Besides, MSWC plants exhibited the highest content of 1-aminocyclopropane-1-carboxylic acid. Conjugated salicylic acid was highest in the BI-plants, while jasmonic acid-isoleucine was highest in MSWC-plants and C plants. In conclusion, prevailing compost chemical residues upregulate plant growth, phytohormones, and metabolic compounds that can potentially increase plant growth and abiotic stress defense. Future work should investigate the flow of these compounds in plants under abiotic stress.

Learning with compost: digging down into food waste, urban soils and community

ABSTRACT This paper explores human, soil, compost and food waste interactions in a community composting initiative in Australia. Drawing on an ethnographic study in 2 Australian cities – Sydney and Canberra, this paper identifies the emergence of a “composting ethic” among participants that is animated by three forms of learning and doing: (1) noticing and attending, (2) embodying and (3) experimentation. Fieldwork analysis is contextualised in relation to literature from the environmental humanities, discard studies and learnings from First Nations Australians and their ontologies. By bringing these empirics, key literature and ontologies together, this paper aims to deepen understanding of the opportunities and challenges of community composting to reduce negative environmental impacts and support anti-colonial practices of discard. It does this by identifying the characteristics of a composting ethic and the contexts and skills capable of nurturing its emergence. Attention is also paid to what may limit realisation of such an ethic. Overall, this paper aims to generate further applied academic understanding about the unique role – and possibilities – of efforts to revitalise and grow city soils and advance anti-colonial food waste management through community composting.

Effect of Application of Elemental Sulphur Incubated with Different Organic Amendments on Yield and Quality of Groundnut in Sulphur Deficient Inceptisol Soil

Aim: Under intensive farming system, use of high analysis fertilizers with rare use of organic manures, depleted the organic carbon status in the soil leads to decrease in productivity though applying improved technologies. After N, P, K fourth major nutrient now days considered as S (Sulphur) which play important role in oilseed and pulse crop productivity and its application with organics to soil found beneficial. Considering this, the proposed research as “Effect of Application of Elemental Sulphur Incubated with Different Organic Amendments on Yield and Quality of Groundnut in Sulphur Deficient Inceptisol Soil.” was carried out with five organic amendments having different quality and maturity parameters which showed the significant results with yield and quality of Kharif groundnut. Study Design: Randomized Block design with seven treatments and four replications. Place and Duration of the Study: The field research trial was conducted during Kharif 2019 at Post Graduate Farm, College of Agriculture, Kolhapur, Maharashtra, India. Methodology: As per the treatments details, the five organic amendments viz: FYM, Vermicompost, Press mud compost, Poultry manure, and City waste compost were incubated with 40 kg ha-1 elemental Sulphur for 30 days prior to application in field plots. The treatment wise incubated organic amendments and RDF applied to groundnut crop. The initial soil analysis, initial and after incubation, the characteristics and quality and maturity parameters of five organic amendments were analyzed by using standard methods. The growth observations and post-harvest observation of groundnut crop were recorded and data were analyzed statistically. Results: The application of different organic amendments incubated with elemental Sulphur @ 40 kg ha-1 namely FYM, Vermicompost, Press mud compost, Poultry manure, and City waste compost along with RDF to Kharif groundnut in Sulphur Deficient Inceptisol soil, significantly improved yield contributing characters, dry pod, haulm yields, protein and oil content as compared to absolute control and RDF. Amongst the different organic amendments, application of good quality and maturity poultry manure and vermicompost found significantly superior over rest of organic amendments incubated with Sulphur for improving the growth, dry pod, haulm yields, protein and oil content as compared rest of organic amendments.

Mulching with Municipal Solid Waste (MSW) Compost Has Beneficial Side Effects on Vineyard Soil Compared to Mulching with Synthetic Films

Municipal solid waste (MSW) compost represents a sustainable alternative to plastic film for mulching in viticulture. This study investigated the effects of MSW compost on vineyard soil properties, specifically focusing on side effects such as soil temperature and microbial decomposition activity, independently from its role in weed control. The experiment was conducted in a vineyard located in the Mediterranean region (Southern Italy), with six different mulching treatments: black polyethylene (PE) film, black and white biodegradable film, three different amounts of MSW compost (8, 15, and 22 kg plant−1), and a control without mulching. Weed growth was monitored to determine the optimal compost application amount. The 15 kg plant−1 treatment was selected for further analyses, as it did not significantly impact weed growth compared to the control. Results indicated that MSW compost mulching maintained lower soil temperatures compared to other treatments (up to 5 °C in the warmest hours) and reduced the amplitude of the thermal wave up to 50% compared to the non-mulched soil and even more compared to black film mulched soil, particularly during the warmest periods. This suggests that MSW compost can mitigate heat stress on plant roots, potentially enhancing plant resilience and preserving crop production also in stressful growing conditions. Microbial decomposition activity, assessed using the tea bag index, was higher in the MSW compost treatment during spring compared to the control, indicating temperature as a key driver for organic matter decomposition, but this effect disappeared during summer. These findings highlight the potential of MSW compost to support sustainable viticulture by reducing reliance on synthetic mulching materials and promoting environmental sustainability through the recycling of organic municipal waste.

Risk management approach using ash-based amendment blends for remediation of lead-contaminated urban soils and protection of public health

Anthropogenic activities have left a legacy of contaminated vacant land, which disproportionately affects lower income communities and can have detrimental impacts on human health, particularly children. A management solution is needed to address this widespread lead contamination in urban soils of vacant lots. In this study, high-Fe biosolids incinerator ash (BIA) was evaluated for its ability to sequester soil Pb. Five blends were created using BIA and different amount of other products (dredge, biosolids compost, and yard waste compost) to determine the most effective treatment to reduce Pb bioaccessibility in the soil. The sorption capacity of the BIA for Pb was evaluated by mixing the BIA with Pb(NO3)2 at 1000 to 100,000 ​mg ​Pb/kg BIA. The contaminated soil from Cleveland, OH was treated with five BIA-based blends at a 1:1 (w/w) ratio, and Pb bioaccessibility was evaluated using USEPA Method 1340 ​at pH 2.5 and the Physiologically Based Extraction Test (PBET) at pH 2.5. BIA was a strong sorbent for Pb, sorbing ∼100% of the Pb from solution at 10,000 ​mg/L with only 41% bioaccessibility based on Method 1340 ​at pH 2.5. The blend containing 4.5%, 10%, or 19% BIA reduced the Pb bioaccessibility by 48% from the control based on both bioaccessibility methods. The bioaccessible Pb determined by PBET was less than that by USEPA Method 1340 ​at pH 2.5. However, similar reductions in bioaccessible Pb between blend-treated soils and the unamended soil were observed for all bioaccessibility methods. Plant growth assays showed the blends to have little to no significant impact on clover growth, mortality, or flower production, with the blend containing 10% BIA showing greater biomass yield. Results showed BIA-based blends were able to reduce bioaccessible Pb in the soil. This remediation approach may improve the urban living environment and protects public health.

Compost de resíduo de feedlot num sistema solo - cultivo de alface

The soil-crop systems of the peri-urban area allow the recovery of chemical elements from the manure generated in intensive livestock production, reducing the risk of contamination of groundwater. This study evaluated the effect of the application of different doses of feedlot waste compost on the lettuce crop (Lactuca sativa L.) and on the chemical, physicochemical, and biological properties of the soil. In two consecutive years, greenhouse experiments were carried out applying doses equivalent to 128 and 500 kg ha-1 of nitrogen, determining fresh weight and apparent efficiency of nitrogen recovery in the crop, and in the soil, nitrate content, organic matter, activity overall biological, electrical conductivity, and pH. The yield of the lettuce crop increased between 29 and 55%, with apparent N recovery efficiencies of less than 5%. In the soil, the effects were mainly manifested in the first centimeters, with increases in the contents of organic matter, global biological activity, and electrical conductivity. On the other hand, there were no significant changes in the pH or nitrate content at depths greater than those reached by the roots of the crop.