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Background: Biochar can enhance phytoremediation in petroleum hydrocarbon polluted soils, making it an intriguing soil amendment option for remediating polluted soil. Biochar can improve the fertility of depleted soils through a range of mechanisms. This study can contribute valuable insights into the origin of biochar and enhance our understanding of the efficacy of different biochar types in remediating petroleum hydrocarbon polluted soils. Aims: To assess the efficacy of different biochar types and plant growth in remediating petroleum hydrocarbon polluted soils. Methods: A field experiment was conducted at the automobile workshop (commonly called mechanic village) from July to October 2021, using a randomized complete block design. The land was sectioned into designated plots with three replicates. Maize stalk biochar (MSB) and nipa palm biochar (NPB) were treated differently in each plot at a rate of 20 t ha−1. Plots containing no biochar were used as controls. Initial and final soil analyses were conducted. Results: Preliminary soil assessments revealed higher values of soil bulk density (1.51 g cm−3), moisture content (35.02%), organic carbon (41.01 g kg−1), cation exchange capacity (13.27 cmol kg−1), total petroleum hydrocarbon content (PHCt) (775.83 mg kg−1), cadmium (Cd) (5.41 mg kg−1), chromium (Cr) (25 mg kg−1), lead (Pb) (33.51 mg kg−1), and zinc (Zn) (0.91 mg kg−1) in the polluted soil than in the unpolluted counterpart. The polluted soil displayed lower hydraulic conductivity (Ks) (1.17 cm h−1), available phosphorus (69.46 mg kg−1), manganese (Mn) (6.38 mg kg−1) and iron (Fe) (4.18 mg kg−1) contents than the unpolluted soil. The PHCt, Cd, and Cr were significantly decreased following the application of biochar. NPB recorded the lowest petroleum hydrocarbon (19%), lead (37%), manganese (57%), and zinc (69%) contents, whereas MSB had the lowest cadmium (50%) and chromium (27%) contents when compared with the control. Between heavy metal accumulations in the leaves and fruits, a greater accumulation of Cd, Cr, and Pb was found in the leaves, whereas Ni accumulation was found in the fruits. The highest Cd (47.0 mg kg−1) and Ni (8.3 mg kg−1) accumulations in the leaves were recorded in NPB treated plots. Similarly, Cd (5.3 mg kg−1), Cr (3.7 mg kg−1), Pb (21.6 mg kg−1), and Ni (23.4 mg kg−1) accumulation in the fruits recorded the highest values in the NPB treated plots. The NPB plants were the tallest compared with the other treatments. In addition, NPB plants had the widest leaf area compared with other treatments. Conclusion: The results indicated that the amendment of NPB may be suitable for the phytoremediation of soils polluted with petroleum hydrocarbons. [ABSTRACT FROM AUTHOR]

The use of saline water under drought conditions is critical for sustainable agricultural development in arid regions. Biochar is used as a soil amendment to enhance soil properties such as water-holding capacity and the source of nutrition elements of plants. Thus, the research was carried out to assess the impact of biochar treatment on the morphological and physiological characteristics and production of Solanum lycopersicum in greenhouses exposed to drought and saline stresses. The study was structured as a three-factorial in split-split-plot design. There were 16 treatments across three variables: (i) water quality, with freshwater and saline water, with electrical conductivities of 0.9 and 2.4 dS m− 1, respectively; (ii) irrigation level, with 40%, 60%, 80%, and 100% of total evapotranspiration (ETC); (iii) and biochar application, with the addition of biochar at a 3% dosage by (w/w) (BC3%), and a control (BC0%). The findings demonstrated that salt and water deficiency hurt physiological, morphological, and yield characteristics. Conversely, the biochar addition enhanced all characteristics. Growth-related parameters, such as plant height, stem diameter, leaf area, and dry and wet weight, and leaf gas exchange attributes, such rate of transpiration and photosynthesis, conductivity, as well as leaf relative water content were decreased by drought and salt stresses, especially when the irrigation was 60% ETc or 40% ETc. The biochar addition resulted in a substantial enhancement in vegetative growth-related parameters, physiological characteristics, efficiency of water use, yield, as well as reduced proline levels. Tomato yield enhanced by 4%, 16%, 8%, and 3% when irrigation with freshwater at different levels of water deficit (100% ETc, 80% ETc, 60% ETc, and 40% ETc) than control (BC0%). Overall, the use of biochar (3%) combined with freshwater shows the potential to enhance morpho-physiological characteristics, support the development of tomato plants, and improve yield with higher WUE in semi-arid and arid areas. [ABSTRACT FROM AUTHOR]

Organic soil amendments are a sustainable option for modifying soil structure and improving plant performance in the face of abiotic stressors such as drought and soil salinity. Of these amendments, biochar and compost have the added benefits of carbon sequestration and waste recycling. Establishment studies were conducted on tall fescue (Festuca arundinacea Schreb.) (syn., Schedonorus arundinaceus (Schreb.) Dumort and Lolium arundinaceum (Scop.) Holub) to assess the potential inhibition of establishment by compost and biochar products. Both green waste and biosolid compost impaired establishment rates, while biochar did not. In the field study, the green waste treatments were slower to reach 50% coverage than the untreated control or when biochar was added to the soil, but all treatments reached 75% and final coverage at a similar rate. Field application of compost had a positive effect on final root length and volume but a negative effect on tall fescue roots in the greenhouse. The negative effect of higher salts and volatiles in the biosolids compost was reduced when biosolids and biochar were incorporated into the soil simultaneously. This work represents one of the only large-scale field studies on turfgrass establishment comparing the impact of biochar and compost products on turfgrass establishment. [ABSTRACT FROM AUTHOR]

Enhancing soil stability through the incorporation of straw and biochar is well documented. Nevertheless, the combined impact of straw, biochar, and nitrogen supplementation on soil aggregates and organic carbon still needs to be explored, with limited attention given to various sieving methods in the existing literature. Therefore, the current experiment used four sieving methods—routine wet sieving (RoutW), fast-wetting sieving (FastW), slow-wetting sieving (SlowW), and wetting–stirring sieving (WetS)—to investigate the effects of adding straw (0 or 4.5 t ha−1), biochar (from maize straw, 0 or 15 t ha−1), and N (0 or 100 kg ha−1) on soil aggregate stability and soil organic C in silt–loam soil of rainfed farmland in northwest China. The field experiment was started in 2014; soil samples were collected in 2021. The results revealed that straw returned, biochar, and N addition significantly increased soil mean weight diameter (MWD) and soil organic C (SOC). Compared to CN0 (zero-amendment) plots, straw returned with nitrogen addition (SN100) significantly increased the MWD of aggregates by 130.3% (RoutW), 121.66% (FastW), 73.94% (SlowW), and 91.78% (WetS) in the 0–30 cm soil layer. The addition of biochar and nitrogen (BN100) treatment showed the most significant effects on the relative slaking index (RSI), relative mechanical breakdown index (RMI), and SOC; compared with CN0 treatment, BN100 plots can reduce RSI and RMI by 42.90% and 54.66% and increase SOC by 53.27% for all soil layers. Therefore, adding organic materials with N can enhance the stability of soil aggregates and SOC of silt–loam soils in northwest China. Integrating biochar as an organic soil amendment in the agricultural practices of northwest China presents a multifaceted solution that addresses soil health, crop productivity, and environmental sustainability. The current study provides valuable insights that support adopting this innovative approach, paving the way for future sustainable agricultural practices that can benefit both the region and the global community. [ABSTRACT FROM AUTHOR]

Simple Summary: To find improved solutions for controlling cadmium pollution in agricultural soil, in situ field experiments were conducted to evaluate the impact of physical measures, phosphate fertilizer application, and soil conditioners on lettuce growth and cadmium absorption. The results revealed that deep plowing and soil covering significantly lowered the cadmium concentration in lettuce. While the application of phosphate fertilizer raised the cadmium concentration in lettuce, the use of diammonium phosphate and calcium magnesium phosphate fertilizer showed a positive correlation with the cadmium concentration, whereas calcium superphosphate displayed a negative correlation. Additionally, upon the application of biochar, attapulgite, and nano-hydroxyapatite, the cadmium concentration in lettuce initially increased with the rising amount of application, but subsequently decreased at higher doses. In conclusion, physical measures are evidently effective in preventing and controlling cadmium pollution. However, the application of phosphate fertilizer can exacerbate cadmium pollution in farmland soil. Soil conditioners, on the other hand, are only effective when used at higher application levels. The findings of this study are crucial for guiding practical cadmium pollution control measures in the field. This study aimed to evaluate the effects of physical measures and the applications of phosphorus fertilizer and soil conditioner on the growth of lettuce (Lactuca sativa) and its uptake of cadmium (Cd). In a solar greenhouse that contained soil enriched with cadmium (Cd) (1.75 ± 0.41 mg/kg) with lettuce used as a test plant, field experimental methods were utilized to explore the influence of physical measures, such as deep plowing and soil covering, and the applications of phosphorus fertilizer, including diammonium phosphate (DAP), calcium magnesium phosphate (CMP), and calcium superphosphate (SSP), and soil conditioners, such as biochar, attapulgite clay, and nano-hydroxyapatite, on the uptake of Cd in lettuce. The results indicated that the concentrations of Cd in the aboveground parts of lettuce were 1.49 ± 0.45, 1.26 ± 0.02, 1.00 ± 0.21, and 0.24 ± 0.13 mg/kg when the soil was plowed 30, 40, and 50 cm deep, respectively, and when the soil was covered with 15 cm, this resulted in reductions of 27.5%, 38.3%, 51.4%, and 88.4%, respectively, compared with the control treatment that entailed plowing to 15 cm. When 75, 150, and 225 kg/ha of phosphorus pentoxide (P2O5) were applied compared with the lack of application, the contents of Cd in the aboveground parts of lettuce increased by 2.0%, 54.5%, and 73.7%, respectively, when DAP was applied; by 52.5%, 48.5%, and 8.1%, respectively, when CMP was applied; and by 13.1%, 61.6%, and 90.9%, respectively, when SSP was applied. When the amounts of biochar applied were 0, 2, 4, 6, 8, 10, and 12 t/ha, the contents of Cd in the aboveground parts of lettuce were 1.36 ± 0.27, 1.47 ± 0.56, 1.80 ± 0.73, 1.96 ± 0.12, 1.89 ± 0.52, 1.44 ± 0.30, and 1.10 ± 0.27 mg/kg, respectively. Under concentrations of 0, 40, 80, 120, 160, and 200 kg/ha, the application of nano-hydroxyapatite resulted in Cd contents of 1.34 ± 0.56, 1.47 ± 0.10, 1.60 ± 0.44, 1.70 ± 0.21, 1.31 ± 0.09, and 1.51 ± 0.34 mg/kg, respectively. The concentrations of Cd in the aboveground parts of lettuce treated with attapulgite clay were 1.44 ± 0.48, 1.88 ± 0.67, 2.10 ± 0.80, 2.24 ± 0.75, 1.78 ± 0.41, and 1.88 ± 0.48 mg/kg, respectively. In summary, under the conditions in this study, deep plowing and soil covering measures can reduce the concentration of Cd in the aboveground parts of lettuce. The application of phosphorus fertilizer increased the concentration of Cd in the aboveground parts of lettuce. The application of higher amounts of DAP and SSP led to greater concentrations of Cd in the aboveground parts of lettuce. The application of higher amounts of CMP caused a lower concentration of Cd in the aboveground parts of lettuce. When biochar, attapulgite clay, and nano-hydroxyapatite were applied, the concentration of Cd in the aboveground parts of lettuce increased in parallel with the increase in the concentration of application when low amounts were applied. In contrast, when high amounts were applied, the concentration of Cd in the aboveground parts of lettuce began to decrease. [ABSTRACT FROM AUTHOR]

Soil salinity is a major challenge in agriculture, particularly in calcareous soils with high calcium carbonate levels. Biochar, produced from biomass pyrolysis, is being considered as a potential solution for mitigating salinity effects. A greenhouse pot experiment was conducted using calcareous soil from a saline field to investigate the effects of sugarcane biochar applied at different rates (0.0%, 2.0%, and 5.0%) on soil properties and wheat (Triticum aestivum L.) growth. Results showed that both Low Rate (2.0% biochar) and High Rate (5.0% biochar) treatments significantly improved soil pH, reduced electrical conductivity (EC), and increased soil organic matter (SOM) content. Plant growth indicators such as plant height, stem diameter, and leaf chlorophyll content also showed significant improvement with biochar application. High Rate had more pronounced effects compared to Low Rate. The analysis confirmed the significant effects of biochar on soil properties and plant growth, indicating its potential as a beneficial soil amendment. Sugarcane biochar has the potential to mitigate salinity stress and enhance crop productivity in calcareous soils. Further research is needed to explore the long-term effects of sugarcane biochar application and its interactions with other soil management practices in different crop systems. These findings highlight the promising role of biochar as a sustainable approach for mitigating salinity stress in agriculture and improving soil quality for crop production. The study's findings highlight the potential industrial applications of sugarcane biochar in addressing soil salinity issues prevalent in calcareous soils, particularly in agriculture. The research underscores the positive impact of biochar on soil attributes, plant growth, and nutrient availability. With its ability to improve soil pH, reduce salinity, increase soil organic matter, and enhance plant growth, sugarcane biochar emerges as a promising soil amendment for agricultural use. This presents an opportunity for industries involved in sustainable agriculture, soil management, and crop enhancement to explore the integration of biochar into their practices. Additionally, the study emphasizes the need for further research and field trials to optimize biochar application rates, assess economic feasibility, and ensure environmental sustainability. The insights gained from this study offer a pathway for industrial stakeholders to explore biochar's role in enhancing soil quality, promoting plant growth, and ensuring sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Salinity is a major environmental problem that adversely affects plant growth by increasing soil osmotic pressure and disrupting plant nutrition. Using organic amendments is a viable tool for reducing physiological and morphological effects of excessive soil salinity on plants. To show the impacts of tea waste, compost and biochar on nutrient status and growth parameters of spinach (Spinacia oleracea L.) raised in salinity conditions, this study has employed factorial CRD with two treatments involving soil salinity (2.5 and 8 dS m−1) and organic materials (spent tea waste (STW), spent tea waste compost (STWC) and spent tea waste biochar (STWB)) at 0 and 3% w/w in three replications. As soil salinity increased from 2.5 to 8 dS m−1, fresh weight and dry matter production decreased by 31.5% and 30.4%, respectively. Phosphorous and potassium concentrations in plant tissue also decreased significantly due to the increase in salinity. Organic amendments (except STW) due to their physicochemical properties increased the nutrients uptake and growth parameters of the plant. Compared to other amendments, biochar reduced salinity effects on plant growth more effectively, which is possibly due to its high nutrient adsorbing and water holding capacity. In saline conditions, the highest potassium to sodium ratio belonged to the biochar treatment, which was 3.22 and 2.78 times greater than spent tea waste and compost, respectively. Therefore, it was preferred to change the spent tea waste into biochar before being used as soil amendment. [ABSTRACT FROM AUTHOR]

The aim of this study was the characterization and evaluation of applicability as a soil amendment of biochar derived from rose pruning waste at different pyrolysis temperatures (200–500 °C) and process durations (20–60 min). The biochar properties were compared to the raw material. The biochars produced at 300 °C for 40 and 60 min demonstrated the best fuel properties. These variants showed high energy gain rates (77.6 ± 1.5% and 74.8 ± 1.5%, respectively), energy densification ratios (1.35 ± 0.00 and 1.37 ± 0.00, respectively), high heating values (24,720 ± 267 J × g−1 and 25,113 ± 731 J × g−1, respectively), and relative low ash contents (5.9 ± 0.5% and 7.1 ± 0.3%, respectively). Regarding fertilizer properties, such as pH value, ash content, heavy metal content, and pollutant elution, the biochars showed better qualities than the raw material. All tested biochar did not exceed the permissible values for heavy metals, including Cr, Cd, Ni, and Pb. The most optimal properties for soil amendments were noted for biochar variants of 400 °C for 40 min, 450 °C for 20 min, and 500 °C for 20 min. Generally, biochars produced at temperatures ≥400 °C did not inhibit root elongation, except for the material produced at 450 °C for 60 min (4.08 ± 23.34%). Biochars obtained at ≥300 °C showed a positive impact on seed germination (86.67 ± 18.48–100 ± 24.14%). [ABSTRACT FROM AUTHOR]

Sandy and acidic soil conditions are the major factors limiting the production of some vegetable crops in acidic soils. This study aims to examine the effect of various amendments on the growth, yield and mineral nutrients uptake of stem amaranth. Two pot experiments were conducted separately in two generic soils. Six treatments viz. T0 = control (without amendment), T1= lime, T2 = lime + wetland bottom sediment, T3 = lime + vermicompost, T4 = lime + rice straw biochar (RSB) and T5 = RSB were used for both experiments following CRD with four replications. Results revealed that plant heights (45.96 and 50.33 cm) of amaranth grown in alluvial and hill soils, respectively, were the highest in T4 treatment. Similarly, treatment T4 showed the highest fresh (118.53 and 116.11 g pot−1, respectively) and dry biomasses (16.98 and 19.54 g pot−1, respectively) for both soils. For both soils, treatment T4 resulted better nutrient uptake of N, P, K, S, Zn, Fe and Mn by edible stem, while non-amended soil gave the lowest result at all parameters. Analytical values of post-harvest soils indicated that T4 and/or T5 treatments resulted in an improvement in soil pH, organic carbon, total N, exchangeable K and extractable P, S and Zn. Treatment T3 showed elevated concentrations of extractable soils Fe and Mn. The amendment RSB combined with lime can be preferably used in strong acidic soils for cultivation of stem amaranth. [ABSTRACT FROM AUTHOR]

Phaseolus vulgaris is one of the most widely consumed legumes across the globe. It is rich in protein, carbohydrates, fiber, bioactive compounds, and mineral contents. Occurrences of drought under changing climate have posed a challenge to the quality and quantity of the crop yield. Our study, taking Phaseolus vulgaris as a test legume, reports that as a soil amendment, biochar and farmyard manure mitigated drought-induced damage in the plant. The experiment was set up in a greenhouse with 1 m2 blocks together arranged in factorial randomized block design. Water withdrawal was done for 15 days in either vegetative or reproductive stage of the crop to simulate drought conditions. Biochar or Farmyard manure was applied at the rate of 10t ha−1 as soil amendment and each treatment was replicated thrice. Higher photosynthesis (up to 23% and 16%, respectively), leaf protein (41% and 30%, respectively), grain protein (4% and 19%, correspondingly), and in-vitro protein digestibility (60% and 254%, respectively) were noted under application of both the amendments. Grain quality in terms of protein content, in-vitro protein digestibility, and protein fractions of Phaseolus vulgaris was improved under drought due to the addition of biochar and farmyard manure. However, the application of those amendments at the rate of 10t ha−1, especially farmyard manure, had a negative impact on the antinutritional factor (phytic acid) and mineral bioavailability. Between the two amendments studied, farmyard manure proved to be more efficient in promoting the overall grain quality of P. vulgaris, but its inimical effects must be concorded. [ABSTRACT FROM AUTHOR]

Bioretention systems use plants and soil media to treat pollutants in stormwater. Biochar can be an effective amendment to bioretention soil media for removing pollutants due to its adsorption properties. This study evaluates biochar as an amendment to bioretention soil media for the removal of contaminants in stormwater. Columns with varying ratios of biochar to bioretention soil media (0%, 25%, and 50% biochar) were tested to evaluate the removal efficiencies of copper, zinc, phosphorus, nitrogen, and microplastics from stormwater. Five trials were conducted with stormwater collected from parking lot runoff. Results show that the addition of biochar in bioretention systems improves the removal efficiency of zinc (average of 79% in columns with 50% biochar compared to 54% in columns without biochar) and copper (average of 73% in columns with 50% biochar compared to 25% in columns without biochar). Stormwater effluent from the biochar-amended columns also had significantly lower turbidity (21 NTU) than that of the control columns (58 NTU). Consistent leaching of nitrogen and phosphorus species was evident in the control as well as the biochar-amended columns, with average removal efficiencies of −1,114% for total nitrogen and −703% for total phosphorus. Microplastics were effectively removed by all columns, regardless of biochar amendment, with an average removal of 86%. This study indicates that biochar has the potential to reduce metal concentrations in stormwater when used as an amendment to bioretention systems but has a limited impact on nutrients and microplastics. [ABSTRACT FROM AUTHOR]

Soil amendment with biochar from oil palm biomass has been found to improve the quality of the infertile weathered soils and enhance crop productivity in the humid tropics. Meanwhile, the field information on microbial responses to oil palm-derived biochar application and its residual effect in acidic tropical soils is still limited. A field study was carried out over three cropping cycles of sweet corn on a Haplic Acrisol of Peninsular Malaysia. The soil was amended once with oil palm kernel shell (OPKS) biochar before the first cropping cycle, with or without inorganic fertiliser. Soil samples were taken at each harvesting stage and analysed for soil pH, cation exchange capacity (CEC), organic C, total N, available P, microbial biomass (C (MBC), N (MBN), and P (MBP)). Microbial biomass ratios (MBC : MBN, MBC : MBP) were calculated. The total bacterial and fungal populations were quantified from soil genomic DNA, employing qPCR amplification of the 16S rDNA and ITS gene. The sole application of biochar and its combined application with fertiliser, increased soil pH, CEC, organic C and N. Coapplication of OPKS biochar and NPK fertiliser hindered N loss in the second cycle. The bacterial and fungal abundance was stimulated following biochar treatment majorly due to the elevation of soil pH and CEC. The ratio of MBC : MBN had a significant negative correlation with N, signifying that this ratio could reflect soil N content and be used as a soil fertility indicator. [ABSTRACT FROM AUTHOR]

The residual effect of compost and biochar amendment on soil properties and durum wheat response was evaluated under field conditions in a Mediterranean environment. The treatments compared in a randomized complete block experimental design with three replications were: mineral fertilizer (100 kg N ha−1), compost applied at the rate of 25 Mg ha−1, biochar applied at the rates of 10 and 30 Mg ha−1, unfertilized control. Wheat was the second crop included in a sorghum–wheat cropping system and did not receive fertilizer supply. A hierarchical statistical analysis was carried out to investigate how different treatments could impact the cropping system performance. The findings highlight the significant influence of soil properties, particularly total N, WEOC, and TOC, on wheat and protein yield. One year after the amendment and fertilizer application, compost and biochar significantly increased soil total organic carbon content. The highest soil water extractable organic carbon was found with the compost application (76.9 mg kg−1), whereas the lowest value (50 mg kg−1) was with the highest rate of biochar. Soil respiration rates and hydraulic properties were not affected by the investigated treatments. This behavior is probably related to the short experimental duration and to the silty clayey soil texture. Significant correlations were observed between bulk density and water content at pressure heads in the −20 and −100 cm range; this range accounts for the effect of soil macro and mesopores. Multiple linear regression analysis revealed strong predictive power for grain (R2_adj = 0.78; p < 0.001) and protein yield (R2_adj = 0.77; p < 0.001). The highest grain yield (3.36 Mg ha−1) was observed with compost, and the lowest (2.18 Mg ha−1) with biochar at a rate of 30 Mg ha−1. These findings lay the basis for understanding how different soil amendment management may impact soil quality and wheat performance, even in consideration of climate change. [ABSTRACT FROM AUTHOR]

Recycling of phosphorus (P) from feedstocks to soils can provide sustainability in agriculture. In our incubation study, we investigated the effects of adding cow manure-derived vermicompost (CMV), cow manure (CM), sugarcane trash biochar (STB), and triple super phosphate (TSP) to extractable P in a sandy loam soil. P was added to the soil at rates of 0, 50, 100, 200, and 300 mg kg−1 based on their total P contents. The amended soils were incubated for 1, 4, 8, and 16 weeks (wk) at room temperature and extractable P samples were measured (by water, Olsen, Mehlich-3 and Bray and Kurtz) and soil pH was monitored. After 1 wk of incubation, the extractable P values were 1.4 mg kg−1 with STB at the smallest while the highest was 79 mg kg−1 with TSP. The corresponding P values in the CMV and CM amended soils were 33 mg kg−1 and 31 mg kg−1. The reductions of extractable P from 1 to 16 wks of incubation were 40%, 35%, and 80% in the CMV, CM and TSP amended soils, respectively, while they increased from 1.43 mg kg−1 to 6.05 mg kg−1 ((320%) in the STB amended soil. Among the amendments, a significant positive relationship was observed between extractable P and the pH in soils amended with STB. The findings revealed that varying P extractability in soils depends on amendment types and duration of incubation. Sugarcane trash biochar did not exhibit an ability to substitute inorganic P fertilizer for assessing bioavailable P. [ABSTRACT FROM AUTHOR]

Biochar is widely used as a good soil amendment, while knowledge of modified biochar application in tea garden soils contaminated by fluoride (F) and cadmium (Cd) is insufficient. The tea seedling (Camellia sinensis L.) growth assay was performed to evaluate interaction of soil Cd and F and the improving effect of aluminum trichloride-modified corn stalk biochar (Al-BC) on their speciation, phytoaccumulation and phytotoxicity. Results showed that soil F speciation ratio sequence was as follows: residual > exchangeable > organic-bound > water-soluble > Fe/Mn oxide-bound. Soil exchangeable Cd was the largest Cd speciation (>35.6%), probably due to the low pH values in the acid tea gardens. Root F contents showed a strong significant relationship with soluble F contents (r = 0.92, P <.01) and similarly root Cd highly connected with exchangeable Cd (r = 0.86, P <.01). Seedling height, fresh and dry weight, root surface area, length, and photosynthetic pigment showed different sensitivities to F or Cd oxidative stress and toxicity effects, and only root F contents significantly inversely correlated with them (r = 0.74–0.80, P <.01). The interaction of Cd and F, could influence their speciation distribution and antagonized each other in root accumulation. Meanwhile, joint simulation models showed that antagonistic effects were observed in the F and Cd mixture soils for most cases at Enshi. Biochar application reduced bioavailable F and Cd contents, and thus decreased F and Cd accumulation in tea roots and obviously alleviated toxicity effects. For instance, biochar application significantly reduced root F contents, which had 33.2% to 62.2% declines at Enshi and 39.7% to 77.2% declines at Huanggang. Meanwhile, the soil properties were improved as biochar added, with an increase in soil pH, EC, CEC and organic matter. Overall, Al-modified biochar was beneficial environmental materials for reducing both F and Cd bioavailability. [ABSTRACT FROM AUTHOR]

BACKGROUND: The accumulation of microplastics in agricultural soil poses a threat to the sustainability of agriculture, impacting crop growth and soil health. Due to the geocarpy feature of peanut, geocarposphere soil environment is critical to pod development and its nutritional quality. While the effects of microplastics in the rhizosphere have been studied, their impact on peanut pod in the geocarposphere remains unknown. Biochar has emerged as a potential soil agent with the ability to remediate soil contamination. However, the mechanisms of biochar in mitigating the toxic effects of microplastics-contaminated geocarposphere soil on peanut pod development remain largely unexplored. RESULTS: We evaluated the peanut pod performance and microbiome when facing microplastics contamination and biochar amendment in geocarposphere soil. The results showed that microplastics present in geocarposphere soil could directly enter the peanut pod, cause pod developmental disorder and exert adverse effects on nutritional quality. Aberrant expression of key genes associated with amino acid metabolism, lipid synthesis, and auxin and ethylene signaling pathways were the underlying molecular mechanisms of microplastics-induced peanut pod developmental inhibition. However, these expression abnormalities could be reversed by biochar application. In addition, peanut geocarposphere microbiome results showed that biochar application could restore the diversity of microbial communities inhibited by microplastics contamination and promote the relative abundance of bacteria correlated with pathogen resistance and nitrogen cycle of geocarposphere soil, further promoting peanut pod development. CONCLUSION: This study demonstrated that biochar application is an effective strategy to mitigate the toxic effects of microplastics-contaminated geocarposphere soil on pod development and nutritional quality. [ABSTRACT FROM AUTHOR]

Thin layer sediment placement (TLP) is used to build elevation in marshes, counteracting effects of subsidence and sea level rise. However, TLP success may vary due to plant stress associated with reductions in nutrient availability and hydrologic flushing or through the creation of acid sulfate soils. This study examined the influence of sediment grain size and soil amendments on plant growth, soil and porewater characteristics, and greenhouse gas exchange for three key U.S. salt marsh plants: Spartina alterniflora (synonym Sporobolus alterniflorus), Spartina patens (synonym Sporobolus pumilus), and Salicornia pacifica. We found that bioavailable nitrogen concentrations (measured as extractable NH4+‐N) and porewater pH and salinity were inversely related to grain size, while soil redox was more reducing in finer sediments. This suggests that utilizing finer sediments in TLP projects will result in a more reduced environment with higher nutrient availability, while larger grain sized sediments will be better flushed and oxygenated. We further found that grain size had a significant effect on vegetation biomass allocation and rates of gas exchange, although these effects were species‐specific. We found that soil amendments (biochar and compost) did not subsidize plant growth but were associated with increases in soil respiration and methane emissions. Biochar amendments were additionally ineffective in ameliorating acid sulfate conditions. This study uncovers complex interactions between sediment type and vegetation, emphasizing the limitations of soil amendments. The findings aid restoration project managers in making informed decisions regarding sediment type, target vegetation, and soil amendments for successful TLP projects. [ABSTRACT FROM AUTHOR]

Important properties of biochar as an effective soil amendment are its high water-holding capacity (WHC) and inhibition of water evaporation. However, the mechanism and the importance of biochar properties in controlling its own WHC and bound water evaporation remain little known. In this study, wheat straw and pine sawdust biochars were pyrolyzed in N2-flow, CO2-flow, and air-limitation environments at 300–750 ℃, and a series of the produced biochars' properties were characterized to explore the dominant controlling factors of their WHC and bound water evaporation. The results have shown that with the increasing contents of hydrogen, nitrogen, and oxygen as well as such ratios as H/C, and (O + N)/C, WHC of the biochars was also increasing while the evaporation of biochar-bound water was decreasing. With an increase in the other studied factors, such as carbon content, pH, and specific surface area (SSA), WHC of the biochars was decreasing, and the evaporation of biochar-bound water was increasing. That was connected with the fact that biochar-nitrogen was mainly in pyridinic and pyrrolic forms, while oxygen was in the form of C = O and C–O bonds. These forms of nitrogen and oxygen could be the receptors of hydrogen bonds to link to H2O molecules. Aliphatic hydrogen with a weak positive charge could be a donor of hydrogen bonds to link to H2O molecules. However, high carbon content, as well as high SSA, indicated more exposed aromatic carbon (hydrophobic sites) that could suppress the binding of H2O molecules. Additionally, high pH indicated that H2O molecules were dominated by OH–, which generated strong electrostatic repulsion with the negatively charged nitrogen- and oxygen-containing groups of biochar. It was also shown that the nitrogen-containing groups played a more important role (importance – 0.31) in WHC of the biochar than other parameters, including carbon, oxygen, hydrogen, ash contents, pH, SSA (importance from 0.02 to 0.09). Nitrogen, oxygen, and carbon contents had the most important influence on the evaporation of biochar-bound water in all studied factors. Furthermore, wheat straw biochar produced at low pyrolysis temperatures in N2 atmosphere (with high nitrogen and oxygen contents) had the highest WHC and the lowest evaporation of biochar-bound water. Consequently, it can be suggested that biochar rich in nitrogen can be an effective water retention agent and can improve agricultural soil moisture. Highlights: Nitrogen-containing groups (pyridinic and pyrrolic nitrogen) played a crucial role in the improvement of biochar water-holding capacity. Nitrogen- and oxygen-containing groups inhibited the evaporation of biochar-bound water. Biochar rich in nitrogen and oxygen may be an effective water retention agent to maintain soil moisture. [ABSTRACT FROM AUTHOR]

Globally, salinity is an important abiotic stress in agriculture. It induced oxidative stress and nutritional imbalance in plants, resulting in poor crop productivity. Applying silicon (Si) can improve the uptake of macronutrients. On the other hand, using biochar as a soil amendment can also decrease salinity stress due to its high porosity, cation exchange capacity, and water-holding capacity. That's why the current experiment was conducted with novelty to explore the impact of silicon nanoparticle-based biochar (Si-BC) on wheat cultivated on salt-affected soil. There were 3 levels of Si-BC, i.e., control (0), 1% Si-BC1, and 2.5% Si-BC2 applied in 3 replicates under 0 and 200 mM NaCl following a completely randomized design. Results showed that treatment 2.5% Si-BC2 performed significantly better for the enhancement in shoot and root length, shoot and root fresh weight, shoot and root dry weight, number of leaves, number of tillers, number of spikelets, spike length, spike fresh and dry weight compared to control under no stress and salinity stress (200 mM NaCl). A significant enhancement in chlorophyll a (~ 18%), chlorophyll b (~ 22%), total chlorophyll (~ 20%), carotenoid (~ 60%), relative water contents (~ 58%) also signified the effectiveness of treatment 2.5% Si-BC2 than control under 200 mM NaCl. In conclusion, treatment 2.5% Si-BC2 can potentially mitigate the salinity stress in wheat by regulating antioxidants and improving N, K concentration, and gas exchange attributes while decreasing Na and Cl concentration and electrolyte leakage. More investigations at the field level are recommended for the declaration of treatment 2.5% Si-BC2 as the best amendment for alleviating salinity stress in different crops under variable climatic conditions. [ABSTRACT FROM AUTHOR]

The land application of sewage sludge can cause different environmental problems due to the high content of potentially toxic elements (PTEs). The objective of this study was to compare the effect of urban biological sewage sludge (i.e. the waste of activated sludge process) and its derived biochar as the soil amendments on the bioavailability of PTEs and their bioaccumulation by corn (Zea mays L.) under two months of greenhouse conditions. The soil was treated by adding biochar samples at 0 (control), 1, 3, 5% w/w. The diethylenetriamine pentaacetic acid (DTPA)-extractable concentrations of PTEs including Zn, Pb, Cd, Cr, Ni, Fe, and Cu in soil and their accumulation by plant shoot and root were measured. Conversion of the biological sewage sludge into the biochar led to decrease the PTEs bioavailability and consequently decreased their contents in plant tissues. The DTPA extractable metal concentrations of produced biochar in comparison to the biological sewage sludge reduced 75% (Cd), 65% (Cr), 79% (Ni and Pb), 76% (Zn), 91% (Cu) and 88% (Fe). Therefore, the content of Ni, Fe, Zn and Cd in corn shoot was decreased 61, 32, 18 and 17% respectively in application of 5% biochar than of raw sewage sludge. Furthermore, the application of 5% biochar enhanced the physiological parameters of the plants including shoot dry weight (twice) and wet weight (2.25 times), stem diameter (1.70 times), chlorophyll content (1.03 times) in comparison to using 5% raw sewage sludge. The results of the study highlight that application of the biochar derived from urban biological sewage sludge in soil could decrease the risk of PTEs to the plant. [ABSTRACT FROM AUTHOR]

Soil application of treated sewage sludge is considered a beneficial management option for agriculture and environment. Sludge treated with clay minerals or biochar was evaluated as soil amendment, in comparison with limed or untreated sludge. Bentonite, vermiculite, biochar or lime was added to dewatered sewage sludge at 0 and 15% rates, in three replications and air-dried. Then, the treated and untreated sludge were added to two soils, one acid and one alkaline, at 0 (control), 1 and 3% rates, in three replications. The results showed that the pH of acid soil significantly increased compared to control upon addition of treated and untreated sludge at both rates, but remained acidic (<6.0) in all cases except for limed sludge. Upon addition of 3% treated or untreated sludge to both soils, organic carbon (OC) significantly increased compared to control. The same stands for soil available ammonium nitrogen (NH4-N), phosphorus (P), potassium (K), copper (Cu), zinc (Zn) and boron (B) for both soils and rates. Soil total heavy metals, which regulate sludge's agronomic use, were below the legislative limits. However, the 3% addition rate of all kinds of sludge, especially of untreated, to both soils increased the electrical conductivity of saturation extract (ECse >2 dS m−1) at unacceptable levels for sensitive crops and available P, B and Zn 2–3, 2–4 and 6–12 times above the initial, respectively. Consequently, sewage sludge treated with bentonite, vermiculite or biochar could be used as a soil amendment but at rates lower than 3% (≈120 Mg ha−1). [ABSTRACT FROM AUTHOR]

The utilization of biochar's as soil amendments for enhancing nutrient retention in subsoils present potential limitations. To address this issue, we conducted a greenhouse experiment to assess the effects of various biochar's derived from animal manures (swine manure, poultry litter, cattle manure) and plant residues (rice straw, soybean straw, corn straw) when applied to surface of an acidic soil. Our study focused on wheat crops under a no-tillage system, with a subsequent evaluation of the residual impacts on soybeans. The experimental design involved the application of biochar's at different rates i.e. 10 and 20 Mg ha−1, followed by the assessment of their influence on NPK levels, pH, and exchangeable Al in stratified soil layers (0–5, 5–10, 10–15, and 15–25 cm). Furthermore, we investigated the interplay between biochar doses and the application of nitrogen (N) in the top 5 cm of soil, specifically examining NO 3 - , NH 4 + , P and K levels. Our findings revealed that in the top 5 cm of soil, biochar doses and N application significantly affected NO 3 - , NH 4 + , P and K concentrations. However, in deeper soil layers, no significant differences were observed among biochar doses with or without N application. Interestingly, K levels were impacted throughout all soil depths, regardless of the presence or absence of N application. Moreover, biochar application up to a 5 cm depth induced favorable changes in soil pH and reduced exchangeable Al. In contrast, deeper layers experienced a decrease in soil pH and an increase in exchangeable Al following biochar treatment. In conclusion, our study demonstrates that biochar's can effectively retain NPK nutrients, enhance soil pH, and decrease exchangeable Al, independent of the type and dosage of application under a no-tillage system. Nonetheless, the efficacy of biochar amendments may vary with soil depth and type of nutrient, warranting careful consideration for maximizing their benefits in sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Biochar has been recently proposed as a management strategy to improve crop productivity and global warming mitigation. Biochar may be added to soils with the goal to improve the soil properties and relocate an amount of conventional fossil fuel based fertilizers and sequester carbon. Biochar production and incorporation in soil must play a role in climate change mitigation. The need for further clarity on optimizing biochar application to various crop yields is necessary if it is to gain widespread acceptance as a soil amendment. There is urgent need to intensify agricultural production to secure food supply for the ever increasing population especially in developing country like India of the tropics. Biochar proponents have placed on biochar stability in soil and it also includes increased soil fertility and water holding capacity, increased crop production and remediation of contaminated soils. The biochar have potential to feasibly and sustainably sequester/offset over 1 Pg of CO2-carbon equivalents annually. Current carbon market incentives are not sufficient to rapidly increase or maximize the initiation and development of biochar implementation. [ABSTRACT FROM AUTHOR]

The central part of the country in the world classified Maize as their staple and essential crop, but this crop cannot cultivate appropriately in acidic soil. Thus, biochar, silicon and phosphorus observation can act as an agent to improve the growth of Maize in acidic soil. Additionally, biochar, well known for its alkaline properties, can reduce soil acidification and, at the same time, improve crop production. This low pH condition was caused by aluminium, manganese and low of phosphorus. Thus, silicon and phosphorus can improve crop productivity. Using biochar as a soil amendment raises the pH value, alone or in combination. Maize (Zea mays L.) and the acidity of the soil are much related to the application of biochar combined with silicon and phosphorus. Biochar simply can reduce exchangeable soil acidity, but when combined with silicon and phosphorus, it can have a greater influence on reducing soil Al toxicity. The importance of biochar with different rates combined with silicon and phosphorus to increase the pH of soil is still an inconsistent result by various studies. This review summarizes the properties of biochar, silicon and phosphorus and provides the scientific reference for its application to archive high yield of maize and reduce the acidification effect on soil. [ABSTRACT FROM AUTHOR]

Biochar and plant growth-promoting rhizobacteria (PGPR) are widely used as an amendment for soil physicochemical properties and soil bacterial community diversity. In Guangxi, China, we carried out a study to determine how PGPR and biochar influence the soil's environmental stability in an Eucalypt plantation. We applied biochar and PGPR in a contrasting application manner to an acidic red loam soil. Thus, three treatments were set up as 5 × 1010 CFU·mL−1 PGPR-only (MB0), 20 t·hm−2 biochar-only (B20), and co-application of 20 t·hm−2 biochar and 5 × 1010 CFU·mL−1 PGPR (MB20), as well as no biochar and no PGPR (M0B0). Our results indicated that MB20 significantly decreased the soil total nitrogen (TN) and increased the soil total phosphorus (Soil TP), soil ammonium nitrogen (NH4+), and soil water content (SWC) when compared with the control. The MB20 also significantly increased the Simpson, ACE, and Chao indices of the soil bacterial community's diversity relative to the control. We also observed a significant effect of the Soil TN on both the bacterial community and the functional diversity in soil. These findings may indicate that assessing the soil N status is expected to be an essential indicator of the soil microenvironment's response to biochar and PGPR applications. [ABSTRACT FROM AUTHOR]

Biochar is produced by burning biomass under oxygen‐limited conditions, and it has been widely used as a soil amendment to improve soil functions such as nutrient retention. However, whether the impact of biochar application on soil nitrogen (N) transformation and N2O emission varies with the pyrolysis temperature remains unclear, especially in different forest types in subtropical regions. In this study, a 60‐day laboratory incubation experiment was conducted to evaluate the impact of biochar with different pyrolysis temperatures (300°C [BC300], 500°C [BC500], and 800°C [BC800]) on net N transformation rates and N2O emission in soils collected from Castanopsis kawakamii dominated natural forest (NF) and Chinese fir (Cunninghamia lanceolate, CF) plantation in subtropical China. The results showed that the application of biochar significantly increased soil ammonium (NH4+) content (p < 0.001) but reduced nitrate (NO3−) content (p < 0.001) compared with the control. The soil NH4+ content of the BC800 treatment was significantly higher than that of other treatments (p < 0.001). Biochar application significantly reduced soil net N mineralization (NRmin) and nitrification (NRnit) rate (p < 0.001), but increased net ammonification (NRamm) rate (p < 0.001). The application of biochar led to a remarkable decrease in cumulative N2O emission compared to the control (p < 0.001). In particular, soils treated with high‐temperature biochar emitted significantly lower N2O compared to other treatments (p < 0.001). The partial least squares path model demonstrated that biochar influenced N2O emission through a direct effect in NF soil and an indirect effect in CF soil. This study highlights the distinct role of biochar, particularly that produced under high pyrolysis temperatures as a soil amendment to mitigate N2O emission and promote N retention in both subtropical natural and planted forests. [ABSTRACT FROM AUTHOR]

Forest management in drained forested peatlands can negatively affect water quality due to the increase in exports of organic matter and nutrients. Therefore, new methods to alleviate this impact are needed. In laboratory conditions, biochar has been shown to be a strong sorbent of organic and inorganic nutrients due to its high surface area and ion‐exchange capacity. However, evidence of the adsorption capacity in field conditions is lacking. Here, we studied the water purification performance of two different biochar feedstocks (wood‐ and garden residue‐based) in a 10‐day laboratory experiment where we incubated biochar with runoff water collected from drainage ditches in clear‐cut peatland forests. We measured changes in pH and concentrations of inorganic phosphorus (PO4), total dissolved nitrogen (TDN), and dissolved organic carbon (DOC). The biochar with the best adsorbent capacity in the laboratory experiment was then tested in field conditions in a replicated catchment‐scale experiment, where both clear‐cutting and ditch cleaning were performed. We determined the nutrient concentration of water at the inlet and outlet of biochar filters placed in outflow ditches of four catchments. We found that under laboratory conditions wood‐based biochar efficiently adsorbed TDN and DOC, however, it released PO4. Furthermore, we found that the biochar filters reduced TDN and DOC concentration in field conditions. However, the percentage decrease in concentration was dependent on the initial concentrations of nutrients in the water and could be considered low. Moreover, we found that the biochar in the filters increased in TN content over the course of the experiment. This suggests that a wood‐based biochar filter has the potential to be a water protection tool for reducing the export of nutrients from catchments with high nutrient concentration. And that the biochar from the ditches could be applied back to the regenerating forest catchment as a potential soil amendment, closing the nutrient cycle. [ABSTRACT FROM AUTHOR]

Agricultural soils contaminated with heavy metals (HMs) impose a threat to the environmental and to human health. Amendment with biochar could be an eco-friendly and cost-effective option to decrease HMs in contaminated soil. This paper reviews the application of biochar as a soil amendment to immobilise HMs in contaminated soil. We discuss the technologies of its preparation, their specific properties, and effect on the bioavailability of HMs. Biochar stabilises HMs in contaminated soil, enhance the overall quality of the contaminated soil, and significantly reduce HM uptake by plants, making it an option in soil remediation for HM contamination. Biochar enhances the physical (e.g. bulk density, soil structure, water holding capacity), chemical (e.g. cation exchange capacity, pH, nutrient availability, ion exchange, complexes), and biological properties (e.g. microbial abundance, enzymatic activities) of contaminated soil. Biochar also enhances soil fertility, improves plant growth, and reduces the plant availability of HMs. Various field studies have shown that biochar application reduces the bioavailability of HMs from contaminated soil while increasing crop yield. The review highlights the positive effects of biochar by reducing HM bioavailability in contaminated soils. Future work is recommended to ensure that biochars offer a safe and sustainable solution to remediate soils contaminated with HMs. [ABSTRACT FROM AUTHOR]

The soil in a lead–zinc mining area, contaminated with heavy metals like cadmium (Cd) and lead (Pb), poses a risk to crops such as maize. Experiments using biochar and sepiolite as soil ameliorants in potted maize showed these substances can mitigate heavy metal contamination. Biochar increased potassium and phosphorus in the soil and maize, while sepiolite significantly boosted overground phosphorus by 73.2%. Both ameliorants transformed Cd and Pb into a more stable state in the soil, reducing their accumulation in maize, especially with biochar, which effectively inhibited metal migration during leaching events. This study provided insights for further improvement of soil amendments and multi-factor application experiments. [ABSTRACT FROM AUTHOR]

Soil degradation due to loss of soil organic carbon is a serious concern in semiarid agroecosystems. Biochar and other organic char products have long been known to increase soil organic carbon. In this study, three-year field observations were carried out on use of coal char (CC) and biochar (BC) as soil amendments in unirrigated semiarid rangeland soil. Coal was pyrolyzed at three different temperatures of 650, 750, and 800 °C to form CC650, CC750, and CC800, respectively, and BC was obtained from a local commercial producer. Manure, CC, and BC were incorporated in soil at 10% (v/v). Analyses of plant growth (aboveground biomass) and soil properties were performed and compared with the control treatment without char. In all three years, CC applied with manure (CC650M) produced significantly greater grass biomass, by 95, 42, 101%, and BC applied with manure (BCM) increased grass biomass by 89, 39, 52% in 2018, 2019, and 2020, than the controls in the respective years. Soil tests a year after application of char indicated significantly increased soil organic matter (OM) with CC and BC treatments (1.60–2.93%) compared with the control (1.37%). However, further detailed studies are required to investigate CC and BC interactions with soil in unirrigated semiarid rangelands. [ABSTRACT FROM AUTHOR]

In this study, biochar (BC) and hydrochar (HC) composites were synthesized with natural kaolinite clay and their properties, stability, carbon (C) sequestration potential, polycyclic aromatic hydrocarbons (PAHs) toxicity, and impacts on maize germination and growth were explored. Conocarpus waste was pretreated with 0%, 10%, and 20% kaolinite and pyrolyzed to produce BCs (BC, BCK10, and BCK20, respectively), while hydrothermalized to produce HCs (HC, HCK10, and HCK20, respectively). The synthesized materials were characterized using X-ray diffraction, scanning electron microscope analyses, Fourier transform infrared, thermogravimetric analysis, surface area, proximate analyses, and chemical analysis to investigate the distinction in physiochemical and structural characteristics. The BCs showed higher C contents (85.73–92.50%) as compared to HCs (58.81–61.11%). The BCs demonstrated a higher thermal stability, aromaticity, and C sequestration potential than HCs. Kaolinite enriched-BCs showed the highest cation exchange capacity than pristine BC (34.97% higher in BCK10 and 38.04% higher in BCK20 than pristine BC), while surface area was the highest in kaolinite composited HCs (202.8% higher in HCK10 and 190.2% higher in HCK20 than pristine HC). The recalcitrance index (R50) speculated a higher recalcitrance for BC, BCK10, and BCK20 (R50 > 0.7), minimal degradability for HCK10 and HCK20 (0.5 < R50 < 0.7), and higher degradability for biomass and HC (R50 < 0.5). Overall, increasing the kaolinite enrichment percentage significantly enhanced the thermal stability and C sequestration potential of charred materials, which may be attributed to changes in the structural arrangements. The ∑ total PAHs concentration in the synthesized materials were below the USEPA's suggested limits, indicating their safe use as soil amendments. Germination indices reflected positive impacts of synthesized charred materials on maize germination and growth. Therefore, we propose that kaolinite-composited BCs and HCs could be considered as efficient and cost-effective soil amendments for improving plant growth. [ABSTRACT FROM AUTHOR]

The composition of microbial communities and the functioning of ecosystems are greatly influenced by the nutrient inputs. Despite this fact, our knowledge regarding the impact of phosphorus (P) inputs on soil P availability and microbial community structures in subtropical acidic soils remains limited. We hypothesized that diverse P inputs, incubation temperatures, and soil types could significantly alter soil P availability and microbial communities. To address this gap, we conducted a laboratory incubation experiment, investigating the effects of biochar and inorganic P amendments on soil available P, soil pH, acid phosphatase enzymes, and bacterial abundance. We employed two different incubation temperatures (15 °C and 25 °C) using acidic paddy soil and red soil from the subtropical Southern China region. Our results indicate a notable increase in soil pH, reaching 37% and 39% at 15 °C and 40% and 40.6% at 25 °C, respectively, following the application of biochar and inorganic P amendments in paddy soil. In the case of red soil, we observed pH increases of 41% and 43% at 15 °C and 44% and 45% at 25 °C after the application of biochar and inorganic P amendment, respectively. The addition of inorganic P amendment resulted in the highest available P contents in paddy soil, reaching 111.47 mg/kg at 15 °C and 100.17 mg/kg at 25 °C, respectively. However, Proteobacteria decreased after inorganic P addition, which showed that P might not be the only limiting nutrient for various bacterial communities. Bacterial diversity and richness indices were found to be higher after biochar application in both soils. Gemmatimonadetes, Acidobacteria, and Actinobacteria were found to be strongly influenced by incubation temperatures, whereas most of the top abundant bacterial phyla, such as Gemmatimonadetes, Actinobacteria, Chloroflexi, Acidobacteria, Planctomycetes, Firmicutes, Patescibacteria, and Bacteroidetes, were highly dependent on soil type. At the genus level, various important P solubilizing genera (Pseudomonas, Bradyrhizobium, Streptomyces jietaisiensis, Massilia) significantly increased after biochar and inorganic P addition in both soils. The correlation analysis proved that P-solubilizing genera were significantly associated with changes in soil pH, as well as soil available P after biochar and inorganic P addition. Conclusively, in a short-term incubation experiment, inorganic P amendment greatly increased the soil pH and available phosphorus contents compared to biochar and control treatments; however, the microbial community was observed to be strongly associated with biochar application, soil type, and incubation temperature. [ABSTRACT FROM AUTHOR]

Biochar is currently used as a phosphate adsorbent in water and subsequently as a soil amendment. In this study, modified biochar was prepared directly by co‐pyrolysis of MgO and rice straw, and a preliminary ecotoxicological assessment was performed before the application of modified biochar to soil. The effects of single factors, such as pyrolysis temperature, dosage, pH, and coexisting ions, on phosphate adsorption performance were investigated. In addition, after phosphate adsorption, the effects of modified biochar leachate on the germination of corn and rice seeds were examined. The results showed that phosphate adsorption by the modified biochar first increased and then decreased as the pyrolysis temperature increased, with modified biochar prepared at 800 °C showing the greatest adsorption. In addition, a comprehensive cost analysis showed that the best phosphate adsorption effect of modified biochar was achieved at a dosage of 0.10 g and a solution pH of 3. In contrast, the presence of competitive coexisting ions, Cl−, NO3−, CO32−, and SO42−, reduced the phosphate adsorption capacity of the modified biochar. The adsorption kinetics results revealed that the process of phosphate adsorption by the modified biochar was more in line with the pseudo‐second‐order model and dominated by chemisorption. Moreover, the adsorption isotherm results indicated that the process was more in line with the Langmuir model and dominated by monomolecular layer adsorption, with a maximum adsorption of 217.54 mg/g. Subsequent seed germination tests showed that phosphate‐adsorbed modified biochar leachate had no significant effect on the germination rate of corn seeds, whereas it improved the germination rate of rice seeds. Together, these results provide guidance for the application of modified biochar firstly as an adsorbent of phosphate and subsequently as a soil remediator. [ABSTRACT FROM AUTHOR]

Simple Summary: Solenopsis invicta (Hymenoptera: Formicidae), also known as the red imported fire ant, is a social insect and a worldwide invasive pest. Biochar is a widely used soil amendment. In this work, we investigated the effects of varying soil biochar levels on irritability and contact toxicity as well as the behavioral and physiological changes in red fire ant behavior. High doses of biochar were toxic and repulsive to red fire ants, impairing their ability to walk, grasp, attack, and gather while also causing an increase in the activity of enzymes associated with oxidative stress. This study supports the prudent utilization of biochar as well as the prevention and management of red fire ants. Solenopsis invicta, often known as the red imported fire ants (RIFAs), is a well-known global invasive ant species that can be found in agricultural, urban, and natural environments worldwide. Simultaneously, it also inhabits the soil. Biochar is generated by the pyrolysis of organic matter under high-temperature anoxic environments and widely used in agricultural ecosystems and soil amendment. However, to date, it remains unknown as to whether soil application of biochar has a negative effect on RIFAs. In our study, we investigated the toxicity and irritability effects of different amounts of biochar (0%, 1%, 2%, 5%, 10%, and 20%) introduced into the soil on red fire ants; upon comparison with the control soil (0% biochar), the application of 1%, 2%, and 5% biochar did not result in significantly different results. But the utilization of biochar at a concentration over 10% effectively repelled the RIFAs, resulting in their departure from the treated soils. High doses of biochar were able to cause death of red fire ants; the mortality rate of red fire ants reached 55.56% after 11 days of 20% biochar treatment. We also evaluated the effects of biochar on four behaviors of red fire ants, namely aggregation, walking, grasping, and attacking; 20% of the biochar treatment group reduced aggregation by 64.22% and this value was 55.22%, 68.44%, and 62.36% for walking, grasping, and attacking. Finally, we measured the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) enzyme activity and malondialdehyde (MDA) content in red fire ants; the results showed that the activities of the three enzymes increased with the increase in biochar addition, which indicated that a high dose of biochar induced oxidative stress in red fire ants. Our results indicate that biochar has the potential to cause toxicity and repel red imported fire ants (RIFAs) in a manner that is dependent on the concentration. We propose that biochar could be utilized in the control and manufacturing of baits for red fire ant management. This work establishes a foundation for the prevention and management of red fire ants and the logical utilization of biochar. [ABSTRACT FROM AUTHOR]

This study aims to develop and evaluate a locally manufactured carbonization unit with a screw conveyor. Various carbonization temperatures (350, 400, and 450°C) and feeding rates (50, 75, and 100 kg/h) were examined to determine optimal conditions for producing biochar from rice husk (RH). The results revealed that increasing the pyrolysis temperature from 350 to 450°C decreased RH biochar yield, while increasing the feeding rate from 50 to 100 kg/h increased it. Ash content was 22.4% at 350°C for 100 kg/h, and the maximum value was 31.4% at 450°C and 50 kg/h. The BET surface area of the biochar increased from 105.71 to 312.32 m2/g at 450°C, with slight non-significant changes at a 100 kg/h feed rate. RH biochar showed decreasing H and O values with higher temperatures and lower feed rates. RH biochar at 450°C and 50 kg/h showed increased macro porosity and surface area, rendering it suitable for agricultural application as a soil amendment. [ABSTRACT FROM AUTHOR]

Intensive agriculture has led to widespread losses of native grasslands. Restoration projects are trying to reestablish native communities. However, the poor quality and altered food webs of former agricultural soils act as barriers to establishing diverse plant communities. Soil amendments such as biochar have been used to improve soil quality and increase crop yield, but little research has been on biochar in restoration settings. Eastern Washington University is attempting to restore a former wheat field to native Palouse prairie vegetation. In this study, we compared (1) soil abiotic properties and food webs between Palouse prairie remnants and Eastern Washington University's (EWU) restoration site and (2) tested whether biochar can move soil conditions at EWU's restoration site closer to those of remnant sites. We compared soils from three Palouse prairie remnants and EWU's restoration site, and compared soils at the restoration site that were treated with different levels of biochar. Soil nematodes were extracted and sorted to functional groups as an assay of the structure and functional diversity of the soil food web. The soil at EWU's restoration site had significantly lower nematode abundance, pH, and organic matter compared to prairie remnants. In addition, nematode abundance and pH increased significantly at the EWU site with the addition of biochar, both increasing to conditions similar to what is found at the prairie remnant sites. These results suggest biochar can improve some soil conditions in former agricultural lands even prior to native plant restoration. [ABSTRACT FROM AUTHOR]

The pollution of soils and groundwater by heavy metal pollutants is a widespread environmental problem, particularly in Iran. One cost-effective method to remediate the polluted soils is phytoremediation, in which different plants are used to extract the heavy metals from soil and accumulate them in their organs. In this study, the phytoremediation potential of native plants of Southwestern Iran in removing nickel and lead from polluted soil was assessed separately and in combination with organic amendments of compost and biochar.Hence, the pot experiments were conducted in the greenhouse using soil gathered from the Pazanan oil refineryin Gachsaran, located at Kohgiluyeh and Boyer-Ahmad Province. Then, the hierarchical cluster analysis was applied to classify the different treatments of amendments.The results indicated that the phytoremediation strength of three native species for Ni uptake was C. procera> St. Plumosa > M. sativa; and for Pb uptake was St. Plumosa > C. procera> M. sativa. Also, the utilisation of organic materials originated from urban waste caused to increase in the Ni and Pb accumulation in root and shoot of these species as well as the residual concentration of the metals in soil. Based on the cluster analysis, the treatment of biochar 2% showed the most effect on the residual concentration of heavy metals in soil (1128.00 mgkg−1);the treatment of biochar 1% represented the highest accumulation of metals at the root (158.82 mgkg−1), while all treatments of different amounts of amendments have the same effect on the accumulation of heavy metals in the shoot (151.38 mgkg−1). In general, cluster analysis showed that the organic amendments, especially biochar even at low amounts can improve the phytoremediation capability of the studied native species in removing Ni and Pb from polluted soil. [ABSTRACT FROM AUTHOR]

The biochar amendment plays a vital role in maintaining soil health largely due to its effects on soil microbial communities. However, individual cases and the variability in biochar properties are not sufficient to draw universal conclusions. The present study aimed to reveal how the biochar application affects soil microbial communities. Metadata of 525 ITS and 1288 16S rRNA sequencing samples from previous studies were reanalyzed and machine learning models were applied to explore the dynamics of soil microbial communities under biochar amendment. The results showed that biochar considerably changed the soil bacterial and fungal community composition and enhanced the relative abundances of Acidobacteriota, Firmicutes, Basidiomycota, and Mortierellomycota. Biochar enhanced the robustness of the soil microbial community but decreased the interactions between fungi and bacteria. The random forest model combined with tenfold cross-validation were used to predict biomarkers of biochar response, indicating that potentially beneficial microbes, such as Gemmatimonadetes, Microtrichales, Candidatus_Kaiserbacteria, and Pyrinomonadales, were enriched in the soil with biochar amendment, which promoted plant growth and soil nutrient cycling. In addition, the biochar amendment enhanced the ability of bacteria to biosynthesize and led to an increase in fungal nutrient patterns, resulting in an increase in the abundance and diversity of saprophytic fungi that enhance soil nutrient cycling. The machine learning model more accurately revealed how biochar affected soil microbial community than previous independent studies. Our study provides a basis for guiding the reasonable use of biochar in agricultural soil and minimizing its negative effects on soil microecosystem. Highlights: Biochar considerably affected the soil community composition of bacteria and fungi. 14 bacterial orders and 7 fungal families were enriched in biochar-amended soils. Biochar enhanced positive interactions and the stability of soil community. Biochar led to an increase in soil fungal nutrient patterns. [ABSTRACT FROM AUTHOR]

Soil aggregate is important to soil quality. Straw return is beneficial for soil amendment, but the effects of straw and straw-derived biochar on aggregate formation and stability in paddy soil are unclear. This study carried out a field experiment for 2 years in Northeast China with four treatments: conventional fertilization (CF), straw (ST, 7.5 t ha−1 year−1), biochar (BC, 2.5 t ha−1 year−1), and biochar-based fertilizer (BCF, 0.75 t ha−1 year−1). Compared with the CF and BCF, BC and ST improved the macroaggregates and significantly increased soil total carbon and aggregate organic carbon, indicating a sustained positive role in promoting the formation and stability of aggregates. BC significantly improved aggregate stability. Correlation analysis showed that macroaggregates (2–0.25 mm) can be increased by increasing the heavy fraction organic carbon (HFOC), BC and ST significantly increased the HFOC, and BC had a greater effect. Scanning electron microscopy (SEM) showed that the combination of biochar and soil particles can be captured with strong water scouring. BCF showed an increasing trend in the formation and stability of soil aggregates. In comparison, biochar had a greater effect on promoting the formation of macroaggregates and the stability of soil aggregates with a significant sustainable effect. [ABSTRACT FROM AUTHOR]

Applying biochar amendment and manure in tea plantation ecosystems can diminish soil acidification and degradation. However, the impact of these practices on soil respiration and associated mechanisms remains unclear. In this study, we combined a two-year field experiment and laboratory analyses based on soil properties, functional genes, and microbial co-occurrence networks to explore the determinants of soil respiration intensity in a subtropical tea plantation with biochar amendment and manure application. The results showed that the effect of biochar amendment on soil respiration was unconspicuous. Although biochar amendment increased bacterial richness and Shannon index, biochar amendment did not alter the abundance of species associated with C-cycling functional genes. Besides directly adding recalcitrant C to the soil, biochar also indirectly enhanced C sequestration by weakly increasing soil carbon dioxide (CO2) emissions. However, replacing mineral fertilizer with manure significantly stimulated soil respiration in the tea plantation, resulting in a 36% increase in CO2 emissions over two years. The increase in CO2 emissions under the manure treatment was mainly attributed to the increased soil labile C pool, the activity of hydrolytic enzymes (e.g., cellobiohydrolase and acetylglucosaminidase), and the relative abundance of functional genes associated with the C-cycle. This may also be related to the application of manure that increased the abundance of Gemmatimonadetes and altered ecological clusters in bacterial co-occurrence networks. Our correlation network analysis suggested that Gemmatimonadetes might be the potential hosts for C-cycling genes due to their strong positive correlation with the abundance of C-cycling genes. Overall, these findings provide new insights into soil respiration under biochar amendment and manure application in tea plantations and broaden the options for carbon sequestration in soils. Highlights: Manure application rather than biochar amendment increased acidic soil respiration. Biochar application promoted soil C sequestration in the tea plantation. Manure application stimulated CO2 emissions by altering ecological clusters' abundance. Gemmatimonadetes might be the dominant hosts for C-cycling genes. [ABSTRACT FROM AUTHOR]

Biochar soil amendments, along with non-tillage agriculture, are often proposed as a strategy for carbon sequestration. It is still questionable how the quality of biochar might influence the priming effect on soil organic matter and whether the addition of unprocessed organic amendments will affect biochar stability. In the study, six different biochars and three exogenous organic matter sources were added to two distinct arable soils. CO2 emission was monitored for 100 days of incubation and CO2 flux was estimated. Results showed that biochar increased soil CO2 fluxes. The highest peaks, up to 162 µg C-CO2 h−1 100 g−1, were recorded in treatments with food waste biochars, suggesting that they serve as a source of easily available carbon to soil microbes. Co-application of raw organic materials (manure and fresh clover biomass) enhanced CO2 emission and carbon losses, especially in sandy soil, where 0.85–1.1% of total carbon was lost in the short-term experiment. Biochar properties and content of labile C can stimulate CO2 emission; however, in a long-term period, this contribution is negligible. The findings of our study showed that more attention should be paid to priming effects caused by the addition of exogenous organic matter when applied to biochar-amended soils. [ABSTRACT FROM AUTHOR]

With the global population continuing to increase, the demand for food and energy has escalated, resulting in severe environmental pressures. Traditional methods of food and energy production have left a significant footprint on the environment, primarily due to the emission of greenhouse gases and a notable surge in waste production. Nevertheless, scientists have recently focused on developing sustainable solutions by managing biomass waste and converting it into useful products. Various biomass conversion technologies, including pyrolysis, gasification, and fermentation, have emerged to transform waste materials into valuable commodities like biofuels, fertilizers, and chemicals. These technologies present an alternative to conventional energy production methods and decrease reliance on non-renewable resources. Furthermore, the by-products generated through biomass conversion, such as biochar, possess utility as valuable soil amendments. This review emphasizes the potential of biomass conversion technologies in providing sustainable solutions for waste management, food and energy production, and reducing negative environmental impacts while providing valuable by-products for agricultural use. The focus is on Lebanon, which is facing a waste and energy crisis, with an aim to encourage and promote sustainable practices by highlighting different green waste management technologies. Focusing on the application of biochar in soil, our goal is to provide cost-effective and eco-friendly solutions to various agricultural and environmental challenges in Lebanon. This includes using biochar from biomass waste as a soil amendment to boost crop yields, remediate soil pollution, reduce soil drought stress, and address other related issues. [ABSTRACT FROM AUTHOR]

Soil salinization is a major threat to crop production. Biochar and aluminum sulfate as soil amendments are critical for improving rice (Oryza sativa L.) productivity under saline-sodic conditions. This study explored the effects of rice-husk biochar and aluminum sulfate on rice growth, biomass, yield, and soil properties under saline-sodic conditions. The experiment was carried out in an experimental field located at the Jilin Agricultural University, China. Five treatments, viz., T0 (no biochar, no aluminum sulfate, no nitrogen), T1 (no biochar, no aluminum sulfate, with NPK), T2 (aluminum sulfate and NPK), T3 (biochar and NPK), and T4 (biochar, aluminum sulfate, and NPK), arranged in a completely randomized design with five biological replicates, were assessed. Compared to T0, plant height, tiller number, leaf dry weight, panicle dry weight, sheath dry weight, stem dry weight, and total dry biomass significantly increased by 14.67%, 56.39%, 60.13%, 59.53%, 39.00%, 58.36%, and 55.99%, respectively, with T1. Compared to T0, the grain yield significantly increased by 82.79% with T1. Additionally, biochar and aluminum sulfate applications significantly decreased the Na+ concentration in different rice organs and considerably increased the K+ concentration and consequently, the K+/Na+ ratio. Moreover, compared to the control, the soil pH, Ca2+, Mg2+, CO32-, and Cl- concentrations under T1, T2, T3, and T4 treatments were substantially improved. Therefore, biochar and aluminum sulfate applications can alleviate saline-sodic stress, improve soil health, and increase rice productivity on saline-sodic soils. The study findings are anticipated to help develop new management strategies for improving rice production under saline-sodic conditions. [ABSTRACT FROM AUTHOR]

Biochar has been widely recommended as an effective soil amendment for reducing nitrous oxide (N2O) emissions and nitrogen (N) leaching. However, the effects of biochar application to Lei bamboo plantations on soil N2O emissions and N leaching remain unclear. These effects on soil N2O emissions and N leaching were investigated in the present study using five treatments applied with the same amount of N: rice husk at 10 t ha−1 (10H) and 30 t ha−1 (30H), biochar at 10 t ha−1 (10B) and 30 t ha−1 (30B), and no additions (control, CK). Both the 10H and 30H treatments significantly increased cumulative N2O emissions compared to the CK treatment, with an increment of 0.78 and 2.20 kg N ha−1, respectively. The 30B treatment significantly reduced cumulative N2O emissions by 0.90 kg N ha−1, whereas the 10B treatment had no significant effect. The reduction in N2O emissions following the high-rate biochar addition was probably due to the increased pH and the total abundance of nosZ I and nosZ II genes. The 30H treatment significantly increased nitrate N (NO3−–N) and dissolved organic N (DON) leaching by 38% and 170% respectively compared to the CK treatment, and had the largest N loss via N2O emissions and N leaching, while the 30B treatment had the lowest N loss. Partial least squares path modeling revealed that soil chemical properties [ammonium nitrogen (NH4+–N), NO3−–N, DON, dissolved organic C (DOC), total N (TN), soil organic C (SOC), and pH] dominantly affected soil N2O emissions, while the total abundance of denitrifying genes (nirS, nirK, nosZ I, and nosZ II) were the key factors involved in reducing NO3−–N leaching. There was a strong positive correlation between cumulative N2O emissions and N leaching loss, which may be related to excessive N surplus in the soil. Our results suggest that the replacement of rice husk by its biochar at a high-rate would reduce the risk of N2O emissions and N leaching loss effectively from Lei bamboo forests in subtropical China. [ABSTRACT FROM AUTHOR]

This study explores the suitability of different biomass feedstocks for biochar production and their effects on soil health and crop yield. Two planting seasons were conducted, involving cucumber as the test crop and eleven treatments combining biochar and poultry manure. Soil analysis revealed initial soil conditions with high sand content and low pH. Poultry manure and biochar exhibited pH, organic carbon, and nutrient level variations. Significant differences in cucumber growth and yield were observed, with the longest vine length in plots treated with palm kernel husk biochar and poultry manure. Residual effects in the second planting season displayed similar trends. Soil pH, organic carbon, and total nitrogen remained consistent between seasons, while available phosphorus increased significantly in plots amended with goat manure biochar and poultry manure. Calcium, magnesium, potassium, and sodium contents also varied. Fruit length, weight, and yield were significantly improved by biochar treatments, with the combination of palm kernel husk biochar and poultry manure yielding the highest fruit weight. Correlation and structural equation analyses (p < 0.05) highlighted the relationships between plant characteristics, soil properties, and fruit indices, emphasizing the importance of nitrogen and phosphorus in supporting fruit development. The study suggests that biochar application enhances soil nutrients, crop growth, and fruit yields while reducing reliance on chemical fertilizers. It recommends considering biochar for land reclamation and as an alternative to traditional fertilizers, supported by appropriate regulations. [ABSTRACT FROM AUTHOR]

Drought stress (DS) is one of the most destructive abiotic stresses that negatively affects plant growth, and yield. The intensity of DS is continuously increasing due rapid of water sources, less rainfall, and an increase in global warming. The world's population is increasing at an alarming rate which needs a substantial increase in crop production to meet global food needs. Therefore, in this context, we must have to increase crop production in the scenarios of rapid climate change and increasing intensity of abiotic stresses. Globally, different measures are used to mitigate the adverse impacts of DS, recently biochar (BC) has emerged as an excellent soil amendment to mitigate the toxic effects of DS and improve crop production. The application maintains membrane integrity, plant water relations, nutrient homeostasis, photosynthetic performance, hormonal balance and osmolytes accumulation, and gene expression thereby improving plant performance under DS. Moreover, BC application under DS also improves soil organic matter, water holding capacity, soil structure stability, and activity of beneficial microbes which can improve the plant performance under DS. In the present review different mechanisms through which BC mitigates the adverse impacts of DS on plants are discussed. This review provides new suggestions on the role of BC in mitigating the adverse impacts of DS. [ABSTRACT FROM AUTHOR]

Two of the most significant issues confronting arid and semi-arid countries are soil degradation and the need to reclaim sandy soils and improve their properties to enhance the agricultural area and ensure food security. Many attempts to improve sandy soil properties have been attempted using soil amendments, but further research is needed to explore the combined impact of cost-effective amendments. To that purpose, we investigated the impact of various soil amendments, including single and combination applications of synthetic Super Absorbent Polymer (SAP), compost, and biochar, on sandy soil physiochemical characteristics and bean (Vicia faba L.) production and quality throughout three growing seasons. In a randomized complete block design with three replicates per treatment, different treatments such as control (without application), lower dose of SAP (SAP1), higher dose of SAP (SAP2), biochar, compost, SAP1 plus biochar, SAP1 plus compost, SAP2 plus biochar, SAP2 plus compost, and biochar plus compost were used. The combined treatments, such as SAP2 plus biochar (T8), SAP2 plus compost (T9), and biochar plus compost (T10), improved soil physiochemical characteristics and crop production significantly. Application of T10 decreased soil bulk density by 15%, 17%, and 13% while increasing soil available water by 10%, 6%, and 3% over the first, second, and third growing seasons, respectively, compared to untreated soil (T1). The application of treatment (T9) surpassed other treatments in terms of yield, quality, and economic return, significantly increasing the seed yield by 24%, 26%, and 27% for the first, second, and third season compared with untreated soil. The higher rate of polymer combined with compost could be considered a cost-effective soil amendment to improve sandy soil productivity in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

Biochar is an economical and efficient adsorption material of heavy metals. This study has evaluated physical characterization of biochar produced by co-pyrolysis at 500°C from lobster shells and straw. The availability of biochar reduces cadmium in cadmium-contaminated soil, and improves cadmium fixation. The results revealed that co-pyrolysis process has altered physical characterization of co-pyrolysis biochar compared with individual straw or lobster shell biochar. The incorporation of biochar in the soil has significantly enhanced soil pH, EC, and has reduced available forms of heavy metals in the soil. The biochar has enhanced carbonate-bound metal forms that has directly converted highly utilized metal forms in stable forms in the soil. The application of five biochars has reduced available content of Cd in the soil compared with control. The content of available Cd is in order of L1J3 < L1J1 < L < J < L3J1 < CK after 150 days of incubation, which has decreased available Cd by 58.49%, 54.09%, 51.45%, 50.60%, and 42.42%, respectively. The five biochars treatments of 1L3J were proved as effective soil amendment for remediation of cadmium pollution. It is concluded that co-pyrolysis biochar from lobster shell pyrolysis with mass ratio of 1:3 of straw was most efficient for cadmium fixation in the soil. [ABSTRACT FROM AUTHOR]

Biochar is an effective soil amendment with capabilities of boosting carbon sequestration and enhancing soil fertility, thus enhancing plant growth and productivity. While numerous studies have documented the positive effects of biochar on improving soil properties, a number of studies have reported conflicting results. Therefore, the current study was conducted to evaluate the impact of Prosopis juliflora biochar (0, 2.5, 5.0, and 7.5 t ha−1) on soil biochemical properties in Coastal Kenya to ascertain biochar's potential for soil fertility improvement. A randomized complete block design was used for setting up the experiment with three replicates, while Casuarina equisetifolia L. was planted as the test crop. Soil sampling for nutrient analysis was conducted quarterly for 12 months to assess nutrient dynamics under different biochar rates in the current study. Compared to soil untreated with Prosopis juliflora biochar, the results showed that there was a significant increase in soil pH by 21% following biochar utilization at the rate of 7.5 t ha−1. Total nitrogen was increased by 32% after the biochar application, whereas the total organic carbon was increased by four folds in comparison to biochar-untreated soil. Available phosphorus was increased by 264% following biochar application in comparison to the control treatment. In addition, the application of biochar resulted in an increment in the soil exchangeable cations (Ca2+, K+, Mg2+) across the assessment periods. Soil cation exchange capacity (CEC), bacteria and fungi were enhanced by 95, 33 and 48%, respectively, following biochar application at 7.5 t ha−1 in comparison to untreated soil. In conclusion, these results strongly suggest improvement of soil biochemical properties following Prosopis juliflora biochar application, thus providing potential for soil fertility improvement in regions such as the one in the study. [ABSTRACT FROM AUTHOR]