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Biochar has emerged as a promising soil amendment for improving soil structure. Yet, its impact on rainfallinduced soil erosion varies across individual studies. To address this gap, we conducted a statistical meta-analysis of 174 paired comparisons from 45 published studies to integratedly evaluate the impacts of biochar on rainfall-induced soil erosion through biochar and soil properties, as well as experimental conditions. Overall, biochar significantly reduced soil erosion by 27.86%. The response ratio (lnRR) of biochar-induced soil erosion exhibited significant variability across different subgroups. Concerning biochar properties, a more favorable influence was observed in other sources biochar (e.g., manure and sewage sludge biochar) compared to wood based and crop waste biochar, and those produced at lower pyrolysis temperatures (< 500 °C). Increasing biochar dosage was not consistently effective. The optimal range was 0.8%--2%, resulting in a 36.07% reduction in soil erosion. Regarding the soil properties, a higher sand/clay ratio of soil significantly enhanced the performance of biochar (p < 0.0001). Specifically, an insignificant effect was observed in fine-grained soils, whereas the highest reduction of 52.97% was noted in coarse-grained soils. Moreover, long-term field experiments induced greater reductions in soil erosion with biochar (35.30%) compared to short-term laboratory studies (29.62% and 12.59%). This meta-analysis demonstrates that biochar, as a potential soil amendment, could effectively mitigate rainfall-induced soil erosion by considering a combination of soil properties along with specific biochar properties. [ABSTRACT FROM AUTHOR]

Adding organic soil amendments can improve the physical and hydrological properties of soil, subsequently enhancing fertility for better crop production. In this study, spent Arabica and Columbian coffee wastes and their respective biochars were evaluated as soil amendments to improve the physical and hydrological properties of loamy sand soil and enhance maize (Zea mays L.) crop growth. Spent Arabica coffee (AC) and Columbian coffee (CC) wastes were collected and transformed into biochar through pyrolysis process at 550 °C with a residence time of 3 h and pyrolysis rate of 5 °C per minute. The AC and CC derived biochar were termed as ABC and CBC, respectively. The produced soil amendments were applied to soil at 0% (control), 1%, 3%, and 5% in a column setup. The moisture characteristics, including water infiltration, evaporation, and water retention, were investigated. Thereafter, the prepared amendments were applied to loamy sand soils at 0% (control), 1%, 3%, and 5% (w/w) application rates. Maize growth was then observed for a period of 30 days under greenhouse conditions. Results of the column trials showed that ABC and CBC applied at 5% reduced the cumulative water evaporation by 57%–66% and cumulative infiltration by 124%–181% compared to control. Likewise, 5% application of ABC and CBC resulted in 101 to 130% higher water retention in loamy sand soil. Results of the greenhouse experiment showed that 5% application of ABC and CBC amendments resulted in root biomass of 2.12 and 2.38 g, respectively, as compared to 0.51 g in control treatment. Similar treatments resulted in shoot biomass of 9.70 and 9.93 g respectively, as compared to 7.37 g in control. Likewise, 5% application of CBC and ABC increase plant height from 15.71 to 30.94 cm in ABC and 33.23 cm in CBC. Overall, 5% application of coffee waste-derived biochars significantly reduced water evaporation and infiltration, while increasing soil water retention and maize plant height, root biomass, and shoot biomass. Therefore, spent coffee waste-derived biochar could effectively be employed to improve physical and hydrological properties of loamy sand soils for better crop productivity. [ABSTRACT FROM AUTHOR]

Valorization of peanut shells has recently gained prominence in the context of thermally converting agricultural waste into biochar, a carbon-rich byproduct with significant potential as a soil amendment. The present study delves into understanding the influence of slow (450°C and 500°C) and fast (550°C and 600°C) pyrolysis temperatures with a resident time of 60 and 30 minutes, respectively, on the physico-chemical properties of peanut shell biochar produced in a low-cost kiln. Results of the Scanning Electron Microscopy analysis revealed that increased pyrolysis temperature increased porosity and surface roughness with crystalline deposits. Thermogravimetric analysis showed that increased temperatures contributed to enhanced thermal stability but reduced biochar yield. Pyrolysis temperatures of 450, 500, 550, and 600°C exhibited 32.19, 29.13, 21.8, and 19.43 percent conversion efficiency with organic carbon content of 11.57, 6.48, 8.64, and 7.76 percent, respectively. The intensities of functional groups (C-H and C-O) declined, whereas the intensity of C=C and stable carbon content increased with the rise in temperatures. The concentrations of heavy metals in all biochar samples were below permissible limits outlined by international biochar initiatives. The study concluded that slow pyrolysis at 450°C for 60 minutes resident time is an ideal pyrolytic condition for producing peanut shell biochar in terms of qualitative and quantitative characteristics. [ABSTRACT FROM AUTHOR]

Sustainable soil fertility management is crucial for enhancing productivity in coconut plantations. This study investigated the synergistic effects of king coconut husk (KCH) ash, biochar, and chemical fertilizers on soil properties in a coconut plantation over a short period (4 months). Six treatments were applied: control, chemical fertilizers alone (F), fertilizers with ash (FA), fertilizers with biochar (FB), fertilizers with both ash and biochar (FAB), and fertilizers with half ash and biochar (FA1/2B). Strongly alkaline KCH ash contained significantly higher total and available potassium content levels than mildly alkaline biochar. Data indicated that KCH ash significantly enhanced soil available potassium, electrical conductivity, and organic carbon content compared to the control and F treatments over a short-term period. Even though biochar application demonstrated initial improvements in soil moisture content, a longer study duration may be required to evaluate its influence on other soil parameters comprehensively. Highlighting the synergistic benefits of KCH ash and biochar, FA1/2B treatment exhibited the highest combined index score based on physical, biological, and chemical soil indicators, suggesting its potential for optimizing agricultural outcomes. It emerged as the most promising approach, underscoring the value of exploring sustainable soil amendments derived from agricultural waste streams to promote soil fertility and sustainable coconut production.

In 2019, the experiment was carried out at Jordan University of Science and Technology (JUST). Various soil amendments, including biochar and compost, both with and without the combination of poultry manure, were employed. The experimental design followed a completely randomized layout, with seven distinct treatments: T1 - soil (control), T2 - Biochar (3%) (BC), T3 - compost (3%) (Comp), T4 - poultry manure (3%) (PM 3% (38.2 ton/ha)), T5 - Biochar (3%) + poultry manure (60 ton/ha) (BC+PM 60 ton/ha), T6 - compost (3%) + poultry manure (60 ton/ha) (Comp+PM 60 ton/ha), and T7 - poultry manure (60 ton/ha) (PM 60 ton/ha). The assessment encompassed the examination of various physicochemical characteristics of the soil, including bulk density, porosity, water holding capacity, pH, and EC. Morphological and physiological measurements comprised plant shoots and roots' height and length, leaves number, shoots and roots' fresh and dry weight, leaf relative water content, and chlorophyll content. Additionally, the chemical composition, encompassing crude fibers, crude fats, antioxidant activities, total phenols, flavonoids content, and minerals was evaluated. Physicochemical results revealed that (BC+PM 60 ton/ha) excelled in water holding capacity and porosity, whereas PM 60 ton/ha exhibited the optimal soil pH. In terms of morphological results, (Comp+PM 60 ton/ha) and (PM 3% (38.2 ton/ha)) demonstrated superiority in plant height, shoot fresh and dry weight. The application of (BC) outperformed in root fresh and dry weight and leaf relative water content, while (Comp) exhibited the highest root length. Poultry manure applications scored higher values in chlorophyll content, with (BC+PM 60 ton/ha) recording the highest among them. Chemical analysis revealed that crude fibers were highest with the application of (PM 3% (38.2 ton/ha)), while (control) recorded the highest antioxidant activities, total phenols, and total flavonoids. In terms of minerals content in shoots, (Comp+PM 60 ton/ha) demonstrated the highest nitrogen content. Phosphorus, Potassium, magnesium, and calcium were most abundant in (BC+PM 60 ton/ha). Moreover, PM (60 ton/ha) exhibited the highest sodium content. Notably, the (BC+PM 60 ton/ha) application excelled in physiochemical soil properties, excluding soil pH and EC, while also demonstrating superior mineral content in lettuce plants, except for sodium.

This study examines the pyrolysis of agricultural residues, namely, coconut shells, rice husks, and cattle manure, in a vertical fixed-bed reactor at varying temperatures from 300 to 800 degrees Celsius for biochar production. The research aimed to evaluate the potential of biochar as biofuels, adsorbents, and soil amendments. Proximate, ultimate, and elemental analyses were conducted to determine their composition and caloric values. Several analytical techniques were used in the physical and chemical characterization of the biochar (SEM, FTIR, BET). The results indicated that the highest SBET values were achieved under different conditions for each biochar: 89.58 m2/g for BC-CS-700, 202.39 m2/g for BC-RH-600, and 42.45 m2/g for BC-CD-800. Additionally, all three biochars exhibited the highest caloric values at 600 °C. The results showed that 600 °C is the general optimal temperature to produce biochar from an assortment of biomass materials, considering their use for a variety of purposes. BC-CS-800 had the highest elemental carbon content at 93%, accompanied by a relative decrease in oxygen content. The van Krevelen diagram of biochar products shows that biochars derived from coconut shells and rice husks are suitable for use as fuels. Furthermore, FTIR analysis revealed the presence of oxygen-containing functional groups on the biochar surface, enhancing their pollutant adsorption capabilities. This study provides valuable insights into the scalable and environmentally sustainable production of biochar, emphasizing its role in improving soil quality, increasing energy density, and supporting sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Sustainable soil fertility management is crucial for enhancing productivity in coconut plantations. This study investigated the synergistic effects of king coconut husk (KCH) ash, biochar, and chemical fertilizers on soil properties in a coconut plantation over a short period (4 months). Six treatments were applied: control, chemical fertilizers alone (F), fertilizers with ash (FA), fertilizers with biochar (FB), fertilizers with both ash and biochar (FAB), and fertilizers with half ash and biochar (FA1/2B). Strongly alkaline KCH ash contained significantly higher total and available potassium content levels than mildly alkaline biochar. Data indicated that KCH ash significantly enhanced soil available potassium, electrical conductivity, and organic carbon content compared to the control and F treatments over a short-term period. Even though biochar application demonstrated initial improvements in soil moisture content, a longer study duration may be required to evaluate its influence on other soil parameters comprehensively. Highlighting the synergistic benefits of KCH ash and biochar, FA1/2B treatment exhibited the highest combined index score based on physical, biological, and chemical soil indicators, suggesting its potential for optimizing agricultural outcomes. It emerged as the most promising approach, underscoring the value of exploring sustainable soil amendments derived from agricultural waste streams to promote soil fertility and sustainable coconut production. [ABSTRACT FROM AUTHOR]

Positive relationships have been documented between the amount of biochar added to soils and various aspects of plant growth and fertility such as root, shoot, and fruit production. However, these effects depend on biochar source materials, soil characteristics and species of plant examined. This makes it impossible to systematically compare and generalize findings across previous studies that have used different soils and biochar. We conducted a novel investigation to assess the effects of a single source of biochar (hazelnut wood), in a constructed organic soil, on the different plant tissues in three functionally distinct species: tomatoes (Solanum lycopersicon), green beans (Phaseolus vulgaris), and willow (Salix sp.). Five levels of biochar soil amendment were assessed: 0% (control), 3, 9, and 26% by dry weight. We found a highly significant positive relationship between biochar concentration and total plant biomass (roots + shoots + fruits) in all species, with no significant difference in total biomass response among species. Fruit production increased with increased biochar in both beans and tomatoes. However, tomatoes exhibited significant differences in response among plant tissues; fruit production and shoot biomass increased significantly with biochar, but root tissue did not. Bean germination success increased significantly with biochar concentration. Date of first flowering was earlier with increasing soil biochar in beans but not in tomatoes. Control over both sources of biochar and soil composition in this experiment enables us to conclude that biochar addition can have different impacts on different plants and, in some cases, species-specific impacts on different plant tissues and other measures of fertility. Our results are contrary to prior research that found inhibiting effects of biochar at levels comparable to our 26% treatment. Biochar impacts on soil properties such as CEC and percent base cation saturation do not explain our findings, leading us to conclude that microbial interaction with biochar is an important factor that may explain the positive impacts of soil biochar on plant fertility observed. Further research that repeats this experiment in other soil types, with other biochar sources, and with other plant species is necessary to determine the generalizability of these important findings. [ABSTRACT FROM AUTHOR]

Biochar can improve soil health and fix CO2 by altering soil microenvironment, thus impacting the global carbon cycle and the change of soil ecological environment. Recent studies show that cotton byproduct-derived biochar is a potential effective amendment for soil improvement so that it could play an important role in agricultural and environmental conservation. In this work, research topics on cotton byproduct-derived biochar in soil in last decade and so are systematically reviewed for better understanding of the progresses of cotton byproduct-derived biochar in (i) the morphologic and physicochemical characterization, (ii) latest research hotspots and trends, (iii) the roles in soil reclamation, and (iv) relevant carbon sequestration mechanisms. Finally, the future research directions regarding cotton byproduct-derived biochar mingled to soil environment are discussed. Insight derived from this work would provide scientific basis for promoting more applications of cotton byproduct-derived biochar in soil ecological restoration and carbon fixation. [ABSTRACT FROM AUTHOR]

Biochar is beneficial as a clean, stable, and efficient soil amendment to improve rice quality and yield. However, there are few reports on the effects of no-tillage in combination with biochar application on rice growth, yield, and quality in regenerative rice systems. This study evaluated rice yield, grain quality, multiple antioxidant enzyme activities, and malondialdehyde content under four treatments: rotary tillage alone, rotary tillage + biochar application, no-tillage alone, and no-tillage + biochar. The results showed that the rice yield under no-tillage alone was 15% lower than that under rotary tillage alone, but that biochar application significantly increased rice yield by 10% and 20% under rotary tillage and no-tillage conditions, respectively, which might be attributed to the fact that biochar application increased panicle number, spikelet number per panicle, grain filling rate, and antioxidant enzyme activities. Additionally, biochar application also increased fine rice rate and protein content, meanwhile reducing chalkiness degree and chalky grain rate in both the main-season rice and ratoon-season rice. These results suggest that biochar application could enhance the yield and grain quality of ratoon rice, thus compensating for the no-tillage-induced yield loss. This study reveals the role of biochar in main-season rice and ratoon rice cultivation, providing a valuable reference for improved fertilizer utilization and cleaner agricultural production. [ABSTRACT FROM AUTHOR]

Nitrification is the core step of the soil nitrogen cycle and directly affects the nitrogen use efficiency in agricultural systems. Biochar and gypsum are two important soil amendments widely used in coastal saline farmland. However, little is known about their effects on nitrification and ammonia-oxidizing microorganisms. A one-year pot experiment with three treatments including biochar application (BC), gypsum application (SG), and no amendment (CK) was conducted, and the responses of the nitrification rate, amoA gene copies, and the diversity and community structure of ammonia-oxidizing archaea (AOA) and bacteria (AOB) to biochar and gypsum were evaluated. The results indicated that biochar and gypsum application both resulted in alterations to the soil properties. They both had inhibiting effects on nitrification and AOB amoA gene copies, whereas they had no significant effect on AOA amoA gene copies. Biochar had no significant effect on the diversity indexes of AOA, but it significantly reduced the Shannon index of AOB. Meanwhile, gypsum had no significant influence on the diversity indexes of both AOA and AOB. Biochar and gypsum did not significantly affect the community structure of AOA but did induce changes in that of AOB. In detail, biochar significantly enhanced the relative abundance of the dominant cluster Nitrosospira, whereas gypsum led to a notable increase in the relative abundance of unclassified_o_Nitrosomonadales. The Shannon index of AOB had a significant negative correlation with soil TOC, TN, and NH4+ content, and soil pH was the first primary environmental factor that affected the AOB community structure. In conclusion, biochar and gypsum inhibited nitrification by suppressing the activities of AOB and changed the diversities and community structure of AOB by altering related soil properties. [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]

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 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]

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]

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]

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]

Biochar (Bc) and liquid vermicompost extracts (LVEs) are increasingly being used as biofertilizers in agriculture to promote soil-microbe-crop interactions. However, although both these products can potentially act synergistically due to their complementary characteristics, their co-application in different soils has not yet been investigated. Therefore, firstly, an LVE-activated biochar (BLVE) was experimentally formulated and the persistence of LVE bacteria over a 60-day storage period was determined. The total number of LVE bacteria increased by 10-fold after 7 days and was stable throughout the entire biochar storage period. In addition, changes in the composition of the bacterial community were observed after 30 days of storage, indicating that taxa less represented in pure LVE may be advantaged upon biochar colonization. Secondly, a microcosm experiment was performed to evaluate whether the biological fertility and enzyme activities of two soils, differing in organic matter content, could be enhanced by the addition of LVE-activated biochar. In this experiment, three different doses of Bc, LVE, and BLVE against the carbon-related biological fertility index (i.e., biological fertility index, BFI) and three enzyme activities over a 21-day incubation period were tested. The BLVE treatment yielded the best results (i.e., BFI +32%, enzyme activities +38%). This indicates that Bc and LVEs can act synergistically to promote soil fertility, quality, and microbial activity. By integrating LVE-activated biochar into their soil management practices, farmers could achieve higher crop yields and healthier products. [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]

Poor soil fertility, imbalanced fertilization, and limited use of organic fertilizer by farmers are significant limitations contributing to lower crop productivity in Nepal. Biochar-based organic fertilizers have been identified as efficient soil amendments to improve soil fertility and boost crop yields. In this study, we investigated the effects of biochar-based organic fertilizers on soil properties, fertilizing efficiency, and maize yields in low-productivity Nepalese soil. A field trial was conducted using a randomized complete block design comprising four treatments with three replications: (1) control without biochar (CK), (2) biochar (BC), (3) biochar + manure (BC+M), and (4) urine-enriched biochar + manure (BU+M). Recommended NPK fertilizers were applied to all plots, including the control. Urine-enriched biochar (BU+M) significantly improved soil pH, organic carbon, and soil nutrient levels (N, P, and K) compared to the control (CK). Total N, available P, and K were significantly higher (p < 0.05) in BU+M treatments compared to the other two biochar amendments (BC and BC+M). A similar trend was observed in the NPK uptake by plants, with BU+M outperforming CK, BC, and BC+M. Moreover, BU+M increased (p < 0.05) the partial factor of productivity of N (PFPN) and P (PFPP) compared to CK. The application of urine-enriched biochar resulted in a 62% increase in maize yield compared to the CK. These findings suggest that farmers can improve soil fertility and increase grain production with the use of urine-enriched biochar, which can be easily produced by farmers themselves using locally available feedstocks and cattle urine. [ABSTRACT FROM AUTHOR]

Sandy soil covers a significant portion of Egypt's total land area, representing a crucial agricultural resource for future food security and economic growth. This research adopts the hypothesis of maximizing the utilization of secondary products for soil improvement to reduce ecosystem pollution. The study focuses on assessing the impact of combining phosphogypsum and modified biochar as environmentally friendly soil amendments on loamy sand soil quality parameters such as soil organic carbon, cation exchange capacity, nutrient levels, and wheat yield. The treatments were T1: the recommended NPK fertilizer (control); T2: 2.5 kg phosphogypsum m−2 soil; T3: 2.5 kg rice straw biochar m−2 soil; T4: 2.5 kg cotton stalk biochar m−2 soil; T5: 2.5 kg rice-straw-modified biochar m−2 soil; T6: 2.5 kg cotton-stalk-modified biochar m−2 soil; and T7 to T10: mixed phosphogypsum and biochar treatments. The results revealed that the combined use of phosphogypsum and modified cotton stalk biochar (T10) significantly enhanced soil organic carbon (SOC) by 73.66% and 99.46% in both seasons, the soil available N both seasons by 130.12 and 161.45%, the available P by 89.49% and 102.02%, and the available K by 39.84 and 70.45% when compared to the control treatment. Additionally, this treatment led to the highest grain yield of wheat (2.72 and 2.92 Mg ha−1), along with a significant increase in straw yield (52.69% and 59.32%) compared to the control treatment. Overall, the findings suggest that the combined use of phosphogypsum and modified biochar, particularly cotton-stalk biochar, holds promise for improving loamy sand-soil quality and wheat productivity. [ABSTRACT FROM AUTHOR]

Crop residues in agriculture pose disposal challenges and contribute to air pollution when burned. This study aims to use pigeonpea and maize stalks to produce biochar at different pyrolysis temperatures. Biochar can serve in carbon sequestration, as a soil amendment, and as an alternative fuel source. Pyrolysis was conducted at 400, 500, and 600 °C to examine the effects on physicochemical properties, fuel, and energy related properties. Increase in temperatures resulted in decrease of biochar yield, volatile matter, and O/C and H/C atomic ratios, while ash content and essential nutrients increased. Yield was observed to be higher in pigeonpea stalks derived biochar compared to maize stalks derived biochar at same pyrolysis temperatures. The yields of pigeonpea stalks derived biochar at 400 °C, 500 °C, and 600 °C are 34, 33 and 29%, respectively, and the yields of maize biomass-derived biochar at 400 °C, 500 °C, and 600 °C are 29, 28, and 26%, respectively. The organic carbon content is found to be higher in the biochar samples prepared at 600 °C, i.e., 10.44%, and 10.39% for pigeonpea and maize-derived biochar, respectively. The essential elements of biochar were increased with an increase in pyrolysis temperature except nitrogen which is conversely related to temperature. The biochar obtained through pyrolysis at 400 °C demonstrated superior characteristics compared to biochar produced at other temperatures. It exhibited a higher biochar yield, with approximately 84.60% for pigeonpea and 64.85% for maize fixed carbon content. Additionally, the energy retention efficiency was higher, reaching 67.33% for pigeonpea and 42.70% for maize-derived biochar at a pyrolysis temperature of 400 °C. The fixed carbon recovery efficiency was also notable at around 200.44% for PPS and 142.37% for maize biochar which is higher compared to biochar produced at other temperatures. Furthermore, the higher heating value (HHV) was approximately 30.75 MJ kg−1 for both the biochars, indicating their suitability as alternative solid fuels. A significant CO2 reduction potential of 84 CO2 eq kg−1 and 55 CO2 eq kg−1 was observed for pigeonpea and maize biochar, respectively. Hence, biochar is a promising and effective option for carbon sequestration, offering environmental benefits. Highlights: • Biochar produced from crop residues: a sustainable solution for decreasing atmospheric CO2 levels •The temperature used during pyrolysis has a notable impact on the yield and characteristics of biochar. Biochar produced at 400°C shows superior characteristics, including higher CO2 reduction potential •Biochar from both biomass sources meets the quality criteria for soil carbon sequestration [ABSTRACT FROM AUTHOR]

Straw and biochar, two commonly used soil amendments, have been shown to enhance soil fertility and the composition of microbial communities. To compare the effects of straw and biochar on soil fertility, particularly focusing on soil dissolved organic matter (DOM) components, and the physiochemical properties of soil and microbial communities, a combination of high-throughput sequencing and three-dimensional fluorescence mapping technology was employed. In our study, we set up four treatments, i.e., without biochar and straw (B0S0); biochar only (B1S0); straw returning only (B0S1); and biochar and straw (B1S1). Our results demonstrate that soil organic matter (SOM), available nitrogen (AN), and available potassium (AK) were increased by 34.71%, 22.96%, and 61.68%, respectively, under the B1S1 treatment compared to the B0S0 treatment. In addition, microbial carbon (MBC), dissolved organic carbon (DOC), and particulate organic carbon (POC) were significantly increased with the B1S1 treatment, by 55.13%, 15.59%, and 125.46%, respectively. The results also show an enhancement in microbial diversity, the composition of microbial communities, and the degree of soil humification with the application of biochar and straw. Moreover, by comparing the differences in soil fertility, DOM components, and other indicators under different treatments, the combined treatments of biochar and straw had a more significant positive impact on paddy soil fertility compared to biochar. In conclusion, our study revealed the combination of straw incorporation and biochar application has significant impacts and is considered an effective approach to improving soil fertility. [ABSTRACT FROM AUTHOR]

Cow dung is a kind of high quality and renewable biological resource. Biochar made from cow dung can be used as a soil amendment to improve soil nutrient status. The relationship between soil water and phosphorus is very close, and the water status determines the form, content, and availability of phosphorus. In order to investigate the effects of biochar on soil inorganic phosphorus components, available phosphorus, enzyme activities related to the phosphorus cycle, microbial functional genes, and seedling growth under different soil water conditions were investigated. Field experiments were carried out by setting different water conditions (30%, 60%, and 100%) and biochar addition (0 t hm−2, 2.63 t hm−2, 5.26 t hm−2, and 7.89 t hm−2). The results showed that applying biochar significantly increased the soil's accessible phosphorus content and the phosphorus content in both the aboveground and subsurface parts of P. euphratica seedlings. This is mainly attributable to biochar's direct and indirect effects on soil properties. Because biochar is naturally alkaline, it raises soil pH and reduces acid phosphatase activity in the soil around P. euphratica seedlings in the rhizosphere. Perhaps the alkaline phosphatase level first showed an upward trend due to the combined impacts of water and biochar, and then it started to decline when the biochar addition was increased. Soil phosphorus functional genes phoC, phoD, gcd, and pqqc had an increase in copy number with biochar addition but not without treatment. Indirectly, the biochar treatment increased the soil's phosphorus availability by increasing the population of the phosphate-solubilizing bacteria Fusarium and Sphingomonas. Soil phosphorus availability is positively affected by biochar under various water conditions. This impact is due to chemical and microbiological mechanisms. [ABSTRACT FROM AUTHOR]

Drought stress deteriorates agro-ecosystems and poses a significant threat to crop productivity and food security. Soil amended with biochar has been suggested to mitigate water stress, but there is limited knowledge about how biochar affects the physiology and vegetative growth of quinoa plants under soil water deficits. We grew three quinoa (Chenopodium quinoa Willd.) varieties, Titicaca (V1), Quipu (V2), and UAFQ7 (V3) in sandy loam soil without (B0) and with 2% woodchip biochar (B2) under drought conditions. The drought resulted in significant growth differences between the varieties. V3 performed vegetatively better, producing 46% more leaves, 28% more branches, and 25% more leaf area than the other two varieties. Conversely, V2 displayed significantly higher yield-contributing traits, with 16% increment in panicle length and 50% more subpanicles compared to the other varieties. Woodchip biochar application significantly enhanced the root development (i.e., root biomass, length, surface, and projected area) and plant growth (i.e., plant height, leaf area, and absolute growth rate). Biochar significantly enhanced root growth, especially fresh and dry weights, by 122% and 127%, respectively. However, biochar application may lead to a trade-off between vegetative growth and panicle development under drought stress as shown for V3 grown in soil with woodchip biochar. However, V3B2 produced longer roots and more biomass. Collectively, we suggest exploring the effects of woodchip biochar addition to the soil on the varietal physiological responses such as stomatal regulations and mechanisms behind the increased quinoa yield under water stress conditions. [ABSTRACT FROM AUTHOR]

This work aimed to assess the influence of cacao pod husk biochar treatments combined with the urea fertilizer addition on the growth and yield of pak choy (Brassica chinensis L.). The study used pot trials in a completely randomized design with two factors. The first was the addition of biochar from cacao pod husk, which consisted of 4 levels, namely 0, 62, 125, and 187 g/pot. The second factor was the dosage of urea addition with 4 levels, namely 0, 0.46, 0.93, and 1.40 g/pot. Pak choy was planted in triplicate polybags. Plant parameters included plant height, number of leaves, canopy cover area, fresh yield, water consumption, and water productivity. The results exhibited that adding biochar was significant in terms of parameters. Low dose biochar (62 g/pot) increased plant height, number of leaves, and water productivity, whereas high dose (125 to 187 g/pot) negatively affected pak choy growth and yield. The addition of urea is significant, except for pH and number of leaves. A fertilizer dose of up to 1.40 g/pot positively affected plant growth and yield of the pak choy. The most optimal interaction of the two factors occurred at a biochar dose of 62 g/pot and urea dose of 1.40 g/pot, which produced a maximum crop fresh yield of 111.83 g/plant. This research concluded that biochar from pyrolysis of cacao pod husk can be employed as soil amendment during pak choy cultivation but with controlled doses. [ABSTRACT FROM AUTHOR]

The agronomic use of compost and biochar as soil amendments may exhibit contrasting results in terms of soil fertility and plant nutrition. The effects of the biennial application of biochar, compost and a blend of compost:biochar (90:10; % dw:dw) on the agronomical performance of an organically managed and well established 25-year-old olive orchard was assessed 5 years after the initial application. The agronomical evaluation was based on the assessment of the soil physical, chemical, and biological characteristics, and the assessment of the soil fertility by both crop production and nutritional status of the orchard, and the bioassay with olive plantlets. Biochar mainly benefited the physical properties (bulk density, total porosity, aeration, water retention capacity) of soil, especially in the top 0–5 cm. Compost and its blend with biochar improved microbial activity, soil nutritional status (increasing the content of soluble organic C, N, and P) and favoured the formation of aggregates in soil. The bioassay conducted with young plantlets confirmed the enhanced soil fertility status in the three amended treatments, particularly in the case of biochar and its blend with compost. However, this effect was not significantly observed in the adult plants after 5 years of application, reflecting the slow response of adult olive trees to changes in fertilization. Based on these results, alongside the desirable long-residence time of biochar in soil and the ready availability of compost, the blend of biochar with compost assayed in this study is defined as a valid strategy for preparing high quality soil organic amendments. [ABSTRACT FROM AUTHOR]

Biochar is a promising pyrolysed carbon-enriched soil amendment and has excellent properties for agriculture production and to remediate environmental pollution. A set of reviews were conducted on biochar production by pyrolysis process from various waste biomass which has drawn extensive interest due to the low cost of production with several benefits. As many potential technologies have been developed, there are still several knowledge gaps that have been identified for some key points to contribute a comprehensive study towards soil fertility, nutrient and water retention, soil microbial activity, plant growth and yield, pollution remediation, mitigation of greenhouse gas emission and an improvement in the farmer's economy to achieve maximum profit by adopting environmentally friendly technique "pyrolysis". Therefore, this review explored a detailed study on food waste biochar production by the pyrolysis process and its impact on different applications as an amendment. Slow pyrolysis process at low and medium temperatures is a potential amendment for agriculture production and soil and water remediation by enhancing biochar properties like carbon, BET surface area, cation exchange capacity, zeta potential, and nutrient content, etc. with minimum ash content. The biochar enhances soil water and nutrient retention capacity, crop yield, and improved microbial community at different soil quality. Additionally, food waste to biochar is a realistic adsorbent and economical carbon sequester to mitigate GHG emissions. This review conducted a brief assessment of the knowledge gaps and future research directions for researchers, encouraging investigators, stakeholders, and policymakers to make the best possible decision for food waste valorization. Highlights: • Valorization of food waste to biochar is a promising amendment for agriculture and soil–water remediation. • Lower and medium pyrolysis temperatures qualitatively changed all aspects of biochar properties. • Biochar improves soil fertility, microbial activity, soil water and nutrient retention capacity, and plants growth. • Biochar is a good carbon sequestrator to mitigate greenhouse gas and a bioeconomy product for the farmer's community and policymakers. [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]

Introduction: Biochar is one of the commonly used soil amendments for sustainable agriculture. The effect of biochar on crop yields depends on the quality of the biochar, which is influenced by feedstock type and pyrolysis conditions. Sole application of pineapple waste biochar and compost, and their combination has not been rigorously investigated. In this study, we investigated the effects of pineapple waste biochar and compost applied solely or in combination on growth and yield of pineapple on a coastal savanna Acrisol in Ghana. Methods: The split-plot design with three replications was used, with pineapple varieties as the main plot and fertilizer application rates as the sub-plots. Results and discussion: The results showed that sole application of biochar and compost or their combination as a soil amendment increased pineapple growth and yield as compared to the unamended soil. Biochar applied in combination with compost/or inorganic NPK (nitrogen, phosphorus, and potassium) fertilizer significantly increased plant height and the number of leaves of pineapple plant, which resulted in improved fruits yield of the three (sugar loaf, MD2 and smooth cayenne) pineapple varieties at maturity over control, sole application of biochar, compost and inorganic NPK fertilizer. The Smooth cayenne variety outperformed MD2 and Sugar loaf variety. Conclusion: In conclusion, the results revealed that biochar applied solely or in addition to compost or inorganic NPK fertilizer has the capability to enhance soil quality and improve pineapple yield. Application of biochar in combination with compost/or inorganic NPK improves pineapple growth and yield. [ABSTRACT FROM AUTHOR]

Biochar, as a soil amendment, has been widely confirmed to increase soil carbon sequestration. However, how biochar addition affects soil carbon changes during the vegetation restoration process is still unclear, which constrains our ability to explore biochar's application in the technology of soil carbon sequestration in forests. We conducted an incubation experiment on biochar and dissolved organic matter (DOM) addition to soil at three stages of revegetation (degraded land (DS), plantation forest (PS), and secondary natural forest (NS) in Changting County in Fujian province, China) to investigate the effects of vegetation restoration, biochar, DOM, and their interaction on soil CO2 emission and its relative mechanisms. We found that the accumulative release of CO2-C in the NS and PS soils was 7.6 and 6.8 times higher, respectively, in comparison to that from the DS soil. In the DS, biochar addition significantly increased the accumulative release of CO2-C, soil pH, NH4+-N content, qCO2, phenol oxidase, and peroxidase activities. Peroxidase activities were positively correlated with the accumulative release of CO2-C, and oxidase was the most important direct factor influencing the accumulative release of CO2-C in the DS. However, the accumulative release of CO2-C, soil NH4+-N content, qCO2, β-glucosidase, and N-acetylglucosaminidase activities was significantly reduced after the application of biochar in the PS and NS. These two hydrolases were positively associated with the accumulative release of CO2-C, and hydrolase was the most vital direct factor influencing the accumulative release of CO2-C from the PS and NS soils. The positive effect of DOM addition on CO2 emission under biochar application declined with a vegetation restoration age increase. Our results indicated that biochar could alter microbial physiological processes, inhibit qCO2 and hydrolase activities, and further decrease CO2 emission in relatively fertile soil from the PS and NS; but in the relatively barren soil from the DS, biochar might promote CO2 emission by stimulating microorganisms to enhance qCO2 and oxidase activities. [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]

Biochar is increasingly being recognized as an effective soil amendment to enhance plant health and improve soil quality, but the complex relationships among biochar, plant resistance, and the soil microbial community are not clear. In this study, biochar derived from an invasive plant (Solidago canadensis L.) was used to investigate its impacts on bacterial wilt control, soil quality, and microbial regulation. The results reveal that the invasive plant biochar application significantly reduced the abundance of Ralstonia solanacearum in the soil (16.8–32.9%) and wilt disease index (14.0–49.2%) and promoted tomato growth. The biochar treatment increased the soil organic carbon, nutrient availability, soil chitinase, and sucrase activities under pathogen inoculation. The biochar did not influence the soil bacterial community diversity, but significantly increased the relative abundance of beneficial organisms, such as Bacillus and Sphingomonas. Biochar application increased the number of nodes, edges, and the average degree of soil microbial symbiotic network, thereby enhancing the stability and complexity of the bacterial community. These findings suggest that the invasive plant biochar produces win–win effects on plant–soil systems by suppressing soilborne wilt disease, enhancing the stability of the soil microbial community network, and promoting resource utilization, indicating its good potential in sustainable soil management. [ABSTRACT FROM AUTHOR]

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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]

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]

Background: Biochar is mainly used to enhance soil fertility, microbial activity, improve plant performance and reduce disease incidence. Methods: A greenhouse experiment was designed to investigate the response of biochar on rhizosphere soil chemical properties, enzyme activity, microbial communities, and sugarcane Pokkah boeng disease (PB). Two sugarcane varieties Zhongzhe 9 (Z9) and ROC22, susceptible/resistant to PB, were cultivated and treated with: no biochar, 15 t ha−1 biochar, and 30 t ha−1 biochar. Results: The amendment of 30 t ha−1 of biochar (B2) significantly improve soil pH by 1.50% and 9.61% compared with that of B1 and B0, followed by 0.51% increase by 15 t ha−1 of biochar (B1) compared with that of control (B0). The application of 15 t ha−1 biochar significantly increased available phosphorus (AP) and ammonium nitrogen (NH4+–N) by 209.93 mg kg−1 and 12.1 mg kg−1, while the application of 30 t ha−1 of biochar significantly increased 241.04 mg kg−1 of available potassium (AK) (P < 0.05). Furthermore, biochar application increased the activities of soil acid phosphatase (S-ACP), urease (S-UE), and sucrase (S-SC). Alpha diversity analysis showed that the addition of biochar significantly altered the variety and abundance of rhizosphere microorganisms (P < 0.01) and increased the relative abundance of beneficial microorganisms Rhodanobacteraceae, Stachybotryaceae, Agaricacea, Talaromyces, Nectriaceae, Sistotrema, and Bacillus (P < 0.01). There was a significant decrease in the relative abundance of the soil pathogen Fusarium (P < 0.01). Conclusion: These findings suggested that the application of 15 t ha−1 biochar could bring desirable variations in soil functionalities, modulate soil microbial community by increasing soil health and reduce the disease index of PB. [ABSTRACT FROM AUTHOR]

Rice husk biochar (RHB) is a potential source of available silicon in paddy soil and an ecologically responsive soil amendment for sustainable rice production. The study tested the influence of RHB application methods on rice growth, rice yield, and silicon dynamics in sandy loam soil in a pot experiment. RHB was applied at 5 tons ha−1 as a localized-spot-application (LSA) or top-mixed-application (TMA) with the soil at the upper 7 cm or whole-mixed-application (WMA) within 20 cm of the soil column and at 10 tons ha−1 in the TMA and WMA methods and was compared with a control (CTRL) without biochar. Seedlings of the Koshihikari rice variety were transplanted in each pot, and all treatments were replicated thrice. Compared to the CTRL, the LSA and TMA methods did not influence the mean porewater silicon concentration at the vegetative and reproductive stages. However, the WMA method applied at 5 tons ha−1 increased (p < 0.05) the mean porewater silicon concentration by 12.3 and 39.5% at the vegetative and reproductive stages, respectively, while at 10 tons ha−1, the respective increase was by 26.1 and 32.7%. All biochar application methods at the 5 tons ha−1 rate increased the rice grain yield (p < 0.05) by 21.2% (LSA), 11.3% (TMA), and 47.2% (WMA) compared to the CTRL. Conversely, at 10 tons ha−1, the yield was reduced by 18% in the TMA method, attributable to the immobilization of nitrogen and adsorption of nutrients to biochar surfaces. Our results proved that the choice of biochar application method and rate of application significantly influenced the dissolution of silicon in the porewater, leading to a higher silicon uptake and consequently a higher grain yield. This study provides valuable insights for agricultural practices aiming to enhance silicon dynamics in paddy soil and sustainable rice yield using RHB. [ABSTRACT FROM AUTHOR]

In this work, the properties of biochar produced from green macroalga Ulva intestinalis by pyrolysis were studied at temperatures of 300, 500, and 700 °C. This biochar was characterized in terms of multielemental composition, BET surface area, total pore volume, and biosorption properties toward phosphate ions. Biochar produced at 700 °C–25 m2/g had the highest surface area. The kinetics and isotherms of sorption processes of phosphate ions as sorbate by these sorbents were investigated. Modified biochar was able to remove 84.3% of phosphate ions from wastewater, whereas non-modified biochar—only 40.6%. Hence, biochar enriched with phosphate ions can serve as a valuable soil amendment. Pot experiments performed on winter wheat (Triticum aestivum) with a 3% addition of dry Ulva intestinalis, pristine biochar, and Mg-modified biochar enriched with phosphate ions showed that these amendments stimulated plant growth (length and fresh weight of plants) as well as enlarging the chlorophyll content in leaves. Our results indicate that the production of biochar (pristine and Mg-impregnated) is a sustainable option to valorize the biomass of seaweeds, and to recycle phosphorus from wastewater. [ABSTRACT FROM AUTHOR]

Poultry manure (PM) has demonstrated its potential to enhance crop nutritional quality. Nevertheless, there remains a dearth of knowledge regarding its synergistic effects when combined with wood biochar (B) on the nutrient concentrations in sweet potato leaves (Ipomoea batatas L.) and the mineral content stored in sweet potato storage roots. Hence, a two-year field trial was undertaken during the 2019 and 2020 cropping seasons in southwestern Nigeria, spanning two locations (Owo—site A and Obasooto—site B), to jointly apply poultry manure and wood biochar as soil amendments aimed at enhancing the nutritional quality of sweet potato crop. Each year, the experiment involved different combinations of poultry manure at rates of 0, 5.0, and 10.0 t ha−1 and biochar at rates of 0, 10.0, 20.0, and 30.0 t ha−1, organized in a 3 × 4 factorial layout. The results of the present study demonstrated that the individual application of poultry manure (PM), biochar (B), or their combination had a significant positive impact on the nutrient composition of sweet potato leaves and minerals stored in the sweet potato storage roots, with notable synergistic effects between poultry manure and biochar (PM × B) in enhancing these parameters. This highlights the potential of biochar to enhance the efficiency of poultry manure utilization and improve nutrient utilization from poultry manure. The highest application rate of poultry manure at 10.0 t ha−1 and biochar at 30.0 t ha−1 (PM10 + B30), resulted in the highest leaf nutrient concentrations and mineral composition compared to other treatments at both sites. Averaged over two years, the highest application rate of poultry manure at 10.0 t ha−1 and biochar at 30.0 t ha−1 (PM10 + B30) significantly increased sweet potato leaf nutrient concentrations: nitrogen by 88.2%, phosphorus by 416.7%, potassium by 123.8%, calcium by 927.3%, and magnesium by 333.3%, compared to those in the control (PM0 + B0). The same treatment increased the concentration of sweet potato root storage minerals: phosphorus by 152.5%, potassium by 77.4%, calcium by 205.5%, magnesium by 294.6%, iron by 268.4%, zinc by 228.6%, and sodium by 433.3%, compared to the control. The highest application rate of poultry manure at 10.0 t ha−1 and biochar at 30.0 t ha−1 yielded the highest economic profitability in terms of gross margin (44,034 US$ ha−1), net return (30,038 US$ ha−1) and return rate or value-to-cost ratio (VCR) (263). The results suggested that the application of poultry manure at 10 t ha−1 and biochar at 30 t ha−1 is economically profitable in the study areas and under similar agroecological zones and soil conditions. [ABSTRACT FROM AUTHOR]

Chenopodium quinoa Willd. (quinoa), a highly nutritious pseudocereal, is a promising crop to address global food insecurity challenges intensified by population growth and climate change. However, drought stress remains a significant constraint for quinoa cultivation. The plant exhibits several morphophysiological adaptations to water stress conditions, including root system modifications, reduced growth rate, leaf abscission, and stomatal closure. While these adaptations enhance drought tolerance, they can also negatively impact plant growth, potentially through alterations in root architecture, physiological changes, e.g., stomatal regulations, and anatomical changes. Different studies have suggested that soil amendment with biochar, a pyrolyzed organic material, can improve quinoa growth and productivity under drought stress conditions. Biochar application to the soil significantly enhances soil physiochemical characteristics and maintains plant water status, thereby promoting plant growth and potentially mitigating the negative consequences of drought on quinoa production. This review focuses on the current understanding of quinoa behavior under drought stress and the potential of soil amendment with biochar as a management strategy. We summarize existing research on applying biochar-amended soil to alleviate quinoa drought stress. [ABSTRACT FROM AUTHOR]

Abstract Drought stress poses a significant challenge to maize production, leading to substantial harm to crop growth and yield due to the induction of oxidative stress. Deashed biochar (DAB) in combination with carboxymethyl cellulose (CMC) presents an effective approach for addressing this problem. DAB improves soil structure by increasing porosity and water retention and enhancing plant nutrient utilization efficiency. The CMC provides advantages to plants by enhancing soil water retention, improving soil structure, and increasing moisture availability to the plant roots. The present study was conducted to investigate the effects of DAB and CMC amendments on maize under field capacity (70 FC) and drought stress. Six different treatments were implemented in this study, namely 0 DAB + 0CMC, 25 CMC, 0.5 DAB, 0.5 DAB + 25 CMC, 1 DAB, and 1 DAB + 25 CMC, each with six replications, and they were arranged according to a completely randomized design. Results showed that 1 DAB + 25 CMC caused significant enhancement in maize shoot fresh weight (24.53%), shoot dry weight (38.47%), shoot length (32.23%), root fresh weight (19.03%), root dry weight (87.50%) and root length (69.80%) over control under drought stress. A substantial increase in maize chlorophyll a (40.26%), chlorophyll b (26.92%), total chlorophyll (30.56%), photosynthetic rate (21.35%), transpiration rate (32.61%), and stomatal conductance (91.57%) under drought stress showed the efficiency of 1 DAB + 25 CMC treatment compared to the control. The enhancement in N, P, and K concentrations in both the root and shoot validated the effectiveness of the performance of the 1 DAB + 25 CMC treatment when compared to the control group under drought stress. In conclusion, it is recommended that the application of 1 DAB + 25 CMC serves as a beneficial amendment for alleviating drought stress in maize.

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]

Soil amendments play a crucial role in modern agriculture, as they effectively enhance the planting environment. This study innovatively proposes the use of gel as a crosslinking agent to embed biochar and hydroxyapatite (HAP), thereby preparing a novel soil amendment. Furthermore, this study investigates the soil improvement effects of this amendment as well as its influence on plant growth. This study employed a hydrothermal method to combine corn stalk (CB) or sludge (SB) biochar with HAP at different ratios (0–20%). Subsequently, sodium alginate gel (SA) was utilized to encapsulate the biochar and minerals, successfully forming a ternary composite gel material (corn stalk biochar/sludge biochar–sodium alginate gel-hydroxyapatite: CB/SB-SA-HAP). Finally, the practical effectiveness of this amendment was verified through potted soil experiments. The results indicate that the CB/SB-SA-HAP composite materials exhibited a micrometre-scale spherical structure with well-developed micropores and possess the functional groups of CB/SB, SA, and HAP, along with unique mineral properties. Through pot experiments, it was verified that the composite material effectively enhances multiple soil properties. After 21 days of cultivation, the soil pH values stabilized within the neutral range (pH = 7 ± 0.3) across all treatment groups. Except for the CB0 (CB:HAP = 1:0) and CB2.0 (CB:HAP = 1:2) treatments, the remaining treatments significantly reduced the soil EC values by 3.27% to 47.92%. All treatments significantly increased the contents of alkali-hydrolysable nitrogen (AHN) (34.89~57.91%), available phosphorus (AP) (35.93~56.55%), and available potassium (AK) (36.41~56.80%) in the soil. In comparison, although the SB treatment was more effective in regulating the pH and electrical conductivity (EC) of saline–alkali soil than the CB treatment, it was less effective in promoting plant growth in the short term. Through correlation analysis and redundancy analysis, a significant positive correlation was found between soil pH and ryegrass germination rate and plant height, particularly with the most pronounced impact on soil pH observed in the CB1.0 and SB0 (SB:HAP = 1:0) treatments. This study underscores the potential of CB/SB-SA-HAP composite materials in soil improvement and plant growth promotion, providing valuable insights for soil remediation, enhancement, and plant cultivation advancements in the agricultural sector. [ABSTRACT FROM AUTHOR]

Featured Application: The research outcomes significantly advance sustainable agricultural practices by providing insights into the utilization of organic materials such as digestate and biochar to improve soil fertility, production, mitigate greenhouse gas emissions and pathogen spreading. This study addresses the need for a comprehensive understanding of digestate and biochar in mitigating climate change and improving soil health, crucial for sustainable agriculture within the circular bioeconomy framework. Through a mesocosm experiment, soil was amended with digestates from pilot-scale reactors and two concentrations of biochar produced by pyrolysis of digested sewage sludge and waste wood. The Germination Index (GI) assay assessed phytotoxicity on Lactuca sativa and Triticum aestivum seeds. Greenhouse gas emissions (CO2, CH4, N2O) measurements, soil characteristics analyses, and the study of microbial community structure enriched the study's depth. The GI assay revealed diverse responses among by-products, dilution rates, and plant types, highlighting the potential phyto-stimulatory effects of digestate and biochar water-extracts. While digestate proved to be effective as fertilizer, concerns arose regarding microbial contamination. Biochar application reduced Clostridiaceae presence in soil but unexpectedly increased N2O emissions at higher concentrations, emphasizing the need for further research on biochar's role in mitigating microbial impacts. CO2 emissions increased with digestate application but decreased with a 10% biochar concentration, aligning with control levels. CH4 uptake decreased with digestate and high biochar concentrations. The study underscores the importance of tailored approaches considering biochar composition and dosage to optimize soil greenhouse gas fluxes and microbial communities. [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]

Agriculture plays a fundamental role in India's economy, supporting 70% of rural households. While often perceived as non-productive, agricultural waste harbors materials potentially beneficial to humans through the creation and utilization of biochar in the production and processing of agricultural goods. This study conducts a comprehensive exploration into the advantages and risks associated with biochar application, considering its role as a soil amendment, bioremediation agent, and its broader implications for human health and the environment. Biochar, primarily composed of stable carbon, was initially proposed as a soil amendment to sequester carbon. Efficient resource utilization has emerged as a viable means to address global environmental challenges associated with waste disposal. This review delineates diverse agricultural waste types and sources, identifies related environmental risks, and advocates for government-led measures aligned with circular economy principles to manage such waste. Furthermore, it offers insights into potential management strategies, policy considerations, and practical approaches, fostering sustainable agriculture practices and environmental conservation in India. [ABSTRACT FROM AUTHOR]

Biochar is a soil amendment that has the potential to effectively improve soil salinization. However, there is a paucity of studies on sodium adsorption using biochar, and the adsorption mechanism remains unclear. To better understand the adsorption mechanism of Na+ on the surface of biochar, both pyrochar and hydrochar were produced at different temperatures. The capacity and influencing factors of Na+ adsorption in biochar were analyzed via batch adsorption experiments. Pore filling dominated the Na+ adsorption in the concentration of the NaCl solution when it was ≤100 mg/L, where wheat straw pyrochar (WB, 3.95–4.94 mg/g Na) and poplar wood chip pyrochar (PB, 0.62–0.70 mg/g Na) presented the release and adsorption of Na+, respectively. When the concentration of the NaCl solution was >100 mg/L, the adsorption capacity of WB (25.44–36.45 mg/g) was significantly higher than PB (4.46–6.23 mg/g). Both the adsorption and release of Na+ in hydrochar was insufficient. In a high concentration of NaCl solution, ion exchange became the key mechanism determining the adsorption of Na+ in pyrochar, in which K+ contributed to more than 94% of the Na+ adsorption. The findings proposed strategies for the structural design of biochar used for Na adsorption. These will promote the utilization of solid biowaste for sodium adsorption and the potential of soil salinization amendment for agriculture in arid lands. [ABSTRACT FROM AUTHOR]