Combined Effects Of Biochar Research Articles

The Removal and Mitigation Effects of Biochar on Microplastics in Water and Soils: Application and Mechanism Analysis

Due to their widespread distribution, microplastics (MPs) are endangering the soil ecological environment system, causing water pollution and altering the soil’s physicochemical and microbiological features. Because of its unique pore structure and strong stability, biochar is widely used as an adsorbent. However, the effects of MP–biochar interactions in water and soil environment are still unclear. This review outlines the application and mechanism of biochar as an adsorbent in a water environment for the removal of MPs. Also, biochar serves as remediation material for MPs in soils as it mitigates the adverse effects of MPs on soil properties, enzyme activities and soil microbial community. It was found that woody biochar had the highest yield and was more effective in adsorbing MPs. Further research should focus on the combined effects of biochar and MPs, the environmental risks of biochar, the modification of biochar application of MP-removal technologies, the characterization of MP properties, the remediation of combined contamination of MPs and other pollutants, and the transportation of MPs.

The regulation pathways of biochar and microorganism in soil-plant system by multiple statistical methods: The forms of carbon participation in coastal wetlands

Coastal wetlands possess significant carbon storage capabilities. However, in coastal soil-plant systems augmented with biochar and microorganisms, the mechanisms of these amendments and carbon participation remain unclear. This study utilized pot experiments to explore how Enteromorpha prolifera biochar and Arbuscular mycorrhizal fungi (AMF) affect soil organic carbon (SOC), carbon-related microbes, photosynthetic and osmotic system of Suaeda salsa. The results showed biochar reduced exchangeable sodium percentage by 6.9% through adsorption and ion exchange, and increased SOC content by 34.4%. The abundance of carbon-related microorganisms (Bacteroidota and Chloroflexi) was increased and carbon metabolizing enzyme (cellulase and sucrase) activity in the soil was enhanced. AMF significantly improved plant growth compared with CK, as evidenced by the enhanced dry weight by 2.34 times. A partial least squares pathway model (PLS-PM) and correlation analysis suggested that the combined effect of biochar and AMF could be outlined as two pathways: soil and plant. Biochar increased SOC, improved the growth of soil carbon metabolizing microorganisms, and further promoted the activity of carbon-related enzymes. Additionally, AMF facilitated nutrient absorption by plants through root symbiosis, with biochar further enhancing this process by acting as a nutrient adsorber. These combined effects of biochar and AMF at soil and plant level enhanced the photosynthetic process of Suaeda salsa. The transport of photosynthetic products to the roots can increase the carbon storage in the soil. This study provides quantitative evidence supporting the increase of carbon storage in coastal wetland soil-plant systems through a combined application of biochar and AMF.

Combined effects of biochar and biodegradable mulch film on chromium bioavailability and the agronomic characteristics of tobacco

Biochar (BC) and biodegradable mulch film (BMF) are both commonly used means of production in agriculture. In recent years, most studies have focused on the effects of BC or BMF on soil heavy metal pollution, while they have neglected the combined effects. In this study, a pot experiment was conducted to examine the impacts of BMF, BC, and combined BMF and BC (CMB) on the mobility of chromium (Cr) and the agronomic characteristics of flue-cured tobacco. Compared with the control, BMF, BC, and CMB significantly reduced the concentrations of diethylenetriamine pentaacetic acid (DTPA) extractable Cr in soils by 29.07–29.75%, 45.35–48.54%, and 34.21–37.92%, respectively. In comparison to the application of BMF and BC alone, co-application reduced the availability of Cr in soil via increasing the adsorption of soil Cr and soil enzyme activity, which resulted in the decrease of Cr content and bioconcentration factor and in plants. Moreover, the combined application increased the plant height, stem diameter, leaf area, total root area, root tip number, and root activity of tobacco, which leaded to increase in leaf and root biomass by 11.40–67.01% and 23.91–50.74%, respectively. Therefore, the application of CMB can reduce the heavy metal residues in tobacco leaves and improve tobacco yield and quality.

Combination of biochar and PGPBs amendment suppresses soil-borne pathogens by modifying plant-associated microbiome

Consecutive monoculture regimes lead to the emergence of soil-borne diseases, which in turn impair plant growth and soil health, and restrict sustainable agricultural production. Biochar and plant growth-promoting bacteria (PGPBs) amendment in soil is considered a potential strategy for reducing soil-borne diseases. However, the combined effects of biochar and PGPBs on plant microbiomes and the subsequent consequences on plant performance remain largely unexplored. Here, we investigated the mechanisms on how biochar and biochar combined with a Bacillus synthetic community (SynCom) alleviated replant disease in Radix pseudostellariae by modulating rhizosphere soil protistan and plant microbial communities based on lab and field experiment. First, we found that biochar with Bacillus SynCom treatment increased the abundance of beneficial Bacillus spp. and Pseudomonas spp. after exposure to Fusarium oxysporum. Field experiments showed that biochar alone and combined with Bacillus SynCom improved the physiological traits and main components of Radix pseudostellariae. Besides, we found both two treatments increased Bacillus abundances in the root and soil, and significantly decreased Fusarium oxysporum density in the three compartments. Last, we validated that the combined treatment significantly decreased the relative abundance of pathogenic Ralstonia, promoted the abundance of Bacillus in the root and Paenibacillus in the leaf, and increased the abundance of the predatory protists Cercomonas and Paracercomonas in the soil. In addition, the combined amendment significantly increased the relative abundance of parasitic protists and decreased the plant pathogens. Meanwhile, the abundance of soil parasitic protists exhibited a significantly negative relationship with F. oxysporum density, and positive relationship with Bacillus density. Especially, soil pH and NO3−-N had a significantly indirect and positive effect on the parasitic protists and biomass by influencing bacterial richness of R. pseudostellariae leaf and root. Overall, our results revealed that amendment with combined biochar and Bacillus SynCom efficiently improved soil-borne disease suppression and plant physiological parameters by remodeling the plant and rhizosphere microbiome. This study provides a practical basis for more sustainable agriculture by promoting plant health through the modulation of plant and soil microbiomes.

The combined effect of biochar and organic fertilizer (goat manure) on the growth and yield of peanut crop (Arachis hypogaea L.)

Sandy soils suffer from many problems with physical and chemical properties as well as low productivity of cultivated crops. Biochar and organic fertilizer have been used in agriculture to improve soil fertility, enhance crop productivity, and sequester carbon in the soil. A study was conducted to investigate the effect of biochar (B) from woody materials and gout manure (GM) on the growth and yield of peanut crops (Arachis hypogaea L.) in sandy soil. The experiment was in a randomized complete block design RCBD with three replicates. The treatments were controlled, 10 t ha-1 GM, 2 % B + 10 t ha-1 GM, and 5 % B + 10 t ha-1 GM. The result showed that the addition of 2 % B + 10 t ha-1 GM increased peanut yield by 50 % while the addition of 5 % B + GM 10 t ha-1 increased peanut yield by 82 %. Without biochar, goat manure had yield increases by 25 % compared to a control. Overall, our findings demonstrate that biochar-goat manure combinations have a better performance than GM alone, in terms of yield and plant growth. For future research, we tend to determine the optimal combination of biochar and goat manure for peanut production.

The joint action of biochar and plant roots on U-stressed soil remediation: Insights from bacteriomics and metabolomics

Although biological remediation of U-stressed soil has been studied for a long time, the combined effects of biochar and plant roots are rarely discussed and its influence on rhizosphere microecology are still unknown. Based on pot experiments, we explored the combined efforts of biochar addition and plant roots on U-stressed rhizosphere soil in several ways, including soil physicochemical properties, soil enzyme activities, uranium chemical speciation, bacterial community structure and metabolic pathways. Our results indicates that the content of DTPA-extractable U decreased by 49.31% after biochar and plant roots application, whereas plant roots only treatment just decreased by 25.46%. Further research has found that the pH, CEC, enzyme activities and nutritional level of rhizosphere soil were more significantly improved after biochar and plant roots application. Meanwhile, the abundance and diversity of bacterial community was also upregulated, which was also suggested by the stronger metabolisms of lipids, carbohydrate, nucleotides as well as amino acids. Correlation analyses also certified the positive associations between soil properties, bacterial communities and metabolism. We speculated that the uranium immobilization was mainly attributed to the direct fixation of biochar for its alkalinity, CEC, DOC, etc. and the joint action of biochar and plant roots for their stimulating effects on bacteria. Our findings suggested that combination of biochar and plant roots could limit bioaccessibility of U in a larger extend than plant roots only, which may be a better strategy for rapid remediation of U-streesed soil.

Biochar and Chlorella increase rice yield by improving saline-alkali soil physicochemical properties and regulating bacteria under aquaculture wastewater irrigation

The combined effects of biochar and Chlorella under aquaculture wastewater irrigation in improving saline-alkali soil physicochemical properties, microbial communities, and rice yield, is not yet clear. This study utilized soil physicochemical indicators and gene sequencing to examine the effect of salinity stress, biochar and Chlorella under aquaculture wastewater irrigation on soil properties, bacterial community compositions, and rice production. Treatments included three factors in a randomized complete block design with three replications: (i) Biochar – 40 tons ha −1 (BW) versus no-biochar (BN); (ii) Salinity – 3‰ salinity (SH) versus 1‰ salinity (SL); and (iii) Chlorella – with 107 cells mL −1 Chlorella (CW) versus no-Chlorella (CN). The results revealed that increased salinity adversely affected the soil nutrients (TOC, NO3⁻-N, NH4+-N, Olsen-P), and enzyme activity (urease, sucrase, catalase), resulting in a 9.67% reduction in rice yield compared to SL treatment. However, the close correlation between alterations in soil bacterial communities, functions, and soil physicochemical properties, as well as rice yield, indicated that biochar and Chlorella promoted rice yield by enhancing the physicochemical properties of saline-alkali soil and bacterial community when irrigated with aquaculture wastewater: (1) addition of biochar increased the146.05% rice yield by increasing TOC content, the complexity of bacterial co-occurrence patterns, nitrogen fixation potential, and nitrification potential, (2) addition of Chlorella increased TOC, NO3⁻-N, NH4+-N, enhanced urease, sucrase, catalase activity, and nitrification potential to increased rice yield by 60.29%, and (3) compared with the treatment T3 (SHBNCN), the treatments with biochar (BW) and Chlorella (CW) increased the yield by 561.30% and 445.03% under 1‰ and 3‰ salinity, respectively. These findings provide novel perspectives on the capacity of biochar and Chlorella to improve saline-alkali soil properties and increase rice yield irrigated with aquaculture wastewater.

Succession of bacterial community structure in response to a one-time application of biochar in barley rhizosphere and bulk soils

Biochar is often used as an amendment to enhance soil fertility by directly increasing soil pH and nutrient availability. However, biochar may also improve soil fertility indirectly by altering the succession of bacterial communities that, in turn, may alter nutrient supply and availability. To determine how biochar affects soil bacterial richness and diversity, as well as how bacterial communities respond to biochar across space and time, we studied the rhizosphere and bulk soils of potted barley plants for 2 years. Adding biochar significantly increased bacterial community richness (Chao 1 richness index) by the end of the second year in the rhizosphere (P = 0.037), but in bulk soils, we observed an increase in richness in Year 1 that dissipated by Year 2. In contrast to richness, adding biochar only had a significant effect on bacterial community diversity (Shannon diversity index) in Year 1 seedling stage (P < 0.001), but the effect dissipated thereafter. We also found that adding biochar increased the relative abundances of Actinobacteria and Proteobacteria but decreased the relative abundances of Acidobacteria and Chloroflexi, suggesting these communities were sensitive to biochar inputs. The biochar-sensitive genera belonging to Actinobacteria and Proteobacteria made up 45%–58% of sensitive taxa in both rhizosphere and bulk soils. Of the Proteobacteria sensitive to adding biochar, Nitrosospira and Sphingomonas were most abundant in the rhizosphere relative to bulk soils. However, despite the initial increase of biochar sensitive responders in the rhizosphere, their numbers decreased after 2 years and had 179 fewer genera than bulk soils. Our findings suggest the effect of adding biochar was relatively short-lived and that the influence of the plant phenology was a stronger driver of bacterial community change than biochar inputs 2 years after its application. Altogether, the succession of soil bacterial community structure reflected changes in the soil environment induced by the combined effect of biochar, rhizospheric inputs, and plant phenology, suggesting that changes in microbial community composition observed after amending soils with biochar, may also contribute to changes in soil fertility.

Independent and combined effects of biochar and mineral fertilizers on wheat productivity and soil properties

Independent and combined effects of biochar and mineral fertilizers on wheat productivity and soil properties

Combined effects of biochar and recycled plastic aggregates on mechanical behavior of concrete

AbstractOnly in Europe, every year around 29 million tons of plastic waste are generated and only about 35% of such waste is collected for recycling. This results in huge amounts of plastic waste threatening the environment. One of the possible solutions for disposal can be represented by the concrete industry. Several research works have already studied the use of plastic waste in concrete mix as partial replacement for aggregates, showing that this use of plastics can contribute to reducing the environmental impact of concrete production by saving non‐renewable resources. At the same time, lightweight concrete can be produced but at a non‐negligible cost of a mechanical strength reduction. This work aims at investigating the effects on concrete physical and mechanical performances resulting from the introduction of recycled plastic aggregates in combination with another kind of waste used as filler, namely biochar. Biochar, which is the solid carbonaceous by‐product resulting from wood‐waste pyro‐gasification, can have the role of carbon sequestrating additive in concrete, being able to fix carbon in a stable form in buildings for decades. The experimental findings obtained in this work show that the combination of biochar and recycled plastic waste, which was never investigated before, can help to obtain concretes with satisfactory mechanical performance, which promote circular economy principles. Thanks to biochar addition, the reduction in mechanical properties due to the presence of plastics is extremely limited with respect to control; moreover, these concretes demonstrate better behavior in terms of fracture energy and ductility.

Combined Effects of Biochar and Inhibitors on Greenhouse Gas Emissions, Global Warming Potential, and Nitrogen Use Efficiency in the Tobacco Field

Biochar (BC), nitrification inhibitors (methyl 3-(4-hydroxyphenyl) propionate, MHPP), and urease inhibitors (n-butyl phosphorothioate triamine, NBPT) have emerged as effective soil greenhouse gas (GHG) mitigation strategies in agroecosystems. However, the combined use of BC and inhibitors in karst areas has no available data. Therefore, the combined effects of BC, MHPP, and NBPT on GHG emissions, global warming potential (GWP) and nitrogen use efficiency (NUE) in roasted tobacco cropping systems were studied to improve the understanding in climate mitigation. CO2, CH4, and N2O emissions from soils were measured using static chamber-gas chromatography. Results showed that the combined use of BC and inhibitors significantly increased soil total nitrogen, available potassium, electric conductivity, pH, and soil organic matter compared to the control. The combined use of BC and MHPP or NBPT significantly increased cumulative soil CO2 emissions by 33.95% and 34.25%, respectively. The exponential–exponential function of soil CO2 fluxes with soil moisture and temperature demonstrated good fit (R2: 0.506–0.836). The combination of BC and NBPT increased the cumulative soil CH4 emissions by 14.28% but not significantly compared to the fertiliser treatment. However, the combination of BC and MHPP resulted in a significant reduction in cumulative soil CH4 emissions by 80.26%. In addition, the combined use of BC and MHPP or NBPT significantly reduced the cumulative soil N2O emissions by 26.55% and 40.67%, respectively. The inhibition effect of NBPT was better than MHPP. Overall, the combined use of BC and inhibitors significantly reduced the yield-scaled GWP, markedly increased crop yield and NUE, and mitigated climate change in the southwest karst region.

Combined effects of biochar and plant growth promoting bacteria Pseudomonas putida TSAU1 on plant growth, nutrient uptake of wheat, and soil enzyme activities

Many studies indicate the favorable effect of biochar on soil quality and plant fitness. A few studies on the biochar interactions with rhizosphere bacteria and their impact on plant development and nutrient acquisition have been reported. In this study, pot experiments in a glasshouse were performed to figure out the interactive effect of plant beneficial bacteria Pseudomonas putida TSAU6 and biochar amendment on the wheat (Triticum aestivum L.) growth, nutrient uptake, and soil biological activity. The results demonstrated that root and shoot dry biomass of wheat grown in soil mixed with biochar and combined with P. putida TSAU1 were enhanced significantly compared to the control plants. The nitrogen (N) and phosphorus (P) content in plant biomass were affected by biochar addition and biochar combined with a bacterial inoculant. It was also observed a change in soil enzyme activities, where higher fluorescein diacetate (FDA) and protease activities were observed after biochar application compared to control soil. The addition of biochar combined with bacterial inoculant showed a more profound effect on wheat growth and N, P acquisition. This positive effect is also associated with soil enzyme activities that are involved directly or indirectly in the N and P cycle. These findings confirm the potential of microbial inoculants induced by biochar to improve wheat production.

Biochar and Nitrification Inhibitor (Dicyandiamide) Combination Had a Double-Win Effect on Saline-Alkali Soil Improvement and Soybean Production in the Yellow River Delta, China

Salt stress and nutrient deficiency strongly limited the productivity of coastal saline-alkali land in the Yellow River Delta. Biochar has been widely used to improve soil health and promote crop yield, and the positive effects of nitrification inhibitors on fertilizer use efficiency, especially nitrogen, were also verified. However, there were few types of research on the combined application of biochar and nitrification inhibitor dicyandiamide (DCD) on saline-alkali soil of the Yellow River Delta, China. In this study, five treatments, including no nitrogen (CK), normal NPK (N), NPK + 1%biochar (B), NPK + 2%DCD (D), and NPK + 1%biochar + 2%DCD (BD) were set to investigate the single and combined effect of biochar and DCD on nitrogen transform, soil properties, bacterial community structure, and soybean production. Results showed that BD application inhibited nitrification and increased the soil’s nitrate supply at the flowering stage, which reduced nitrogen waste and met the nitrogen demand for soybean growth. Biochar addition increased the soil’s pH and decreased the soil’s electrical conductivities and accelerated the soil’s macroaggregates formation, with the soil’s average mass diameter and geometric average diameter increasing by 78.69% and 30% in B, and 71.29% and 29.34% in BD relative to CK. Positive effects of inhibitors on soybean production were found in increasing soybean yield, hundred-grain weight, aboveground biomass, etc. Proteobacteria was the dominant phylum in the bacterial communities detected, and bacterial community diversity was significantly explained by nitrate content and soil aggregates (p < 0.05). Soil pH and DCD addition mainly influenced the abundance of the bacterial community, especially Actinobacteria. Biochar with DCD could be a feasible fertilization scheme for the coastal saline-alkali land in the Yellow River Delta, China.

Independent and combined effects of biochar and microbial agents on physicochemical parameters and microbial community succession during food waste composting

This study evaluated the independent and combined effects of biochar and microbial agents on food waste composting. The results indicated that combined addition increased the peak temperature to 63.5 °C and extended the thermophilic periods to 8 days, resulting in the highest organic matter degradation rate (12.7%). Analysis of enzymatic activity indicated that combined addition increased urease and dehydrogenase activity by 22.9% and 26.5%. Furthermore, the degradation of volatile fatty acids also increased by 37.4% with combined addition. Microbial analysis demonstrated that combined addition effectively increased the relative abundances of Enterobacter, Sphingobacterium and Aspergillus, which could be attributed to the optimal environment provided by biochar and stimulation of microbial agents. Moreover, correlation analysis showed a strong interaction between the microbial community and environment with combined addition. In general, combined addition could be beneficial for composting based on the synergistic effects of biochar and inoculation on microorganism.

Agronomic response of sunflower subjected to biochar and arbuscular mycorrhizal fungi application under drought conditions

There is growing interest in developing environment-friendly farming practices that can limit the impact of drought stress in agriculture. The main objective of this study was to investigate the combined effects of biochar and arbuscular mycorrhizal fungi (AMF) on the agronomic responses of sunflower. Field experiments were conducted in the 2018 and 2019 growing seasons in semi-arid environments of Iran. The following treatments were adopted: i) three levels of biochar [0, 2.5 and 5 t ha–1 of biochar called Bl, Bm and Bh, respectively]; and ii) three irrigation levels (50, 30 and 10% of the maximum available water (MAW) called 50MAW, 30MAW and 10MAW, respectively)]; iii) two levels of AMF inoculation (with and without the addition of AMF called +AMF and –AMF, respectively). The experimental design was a randomized complete block design. At flowering, the leaf area index (LAI) was generally higher in the plants subjected to Bh-+AMF (on average 4.95), even if the LAI values changed according to biochar application (Bh > Bm > Bl) and the level of irrigation (50MAW > 30MAW > 10MAW). At harvesting, sunflower seed yield was highest in +AMF and in Bh (on average 53.9 and 51.2 g plants–1, respectively). Sunflower plants subjected to Bh-+AMF showed the highest seed yield under all irrigation levels (79.4, 57.1 and 32.3 g plant–1 in 50MAW, 30MAW and 10MAW, respectively). The application of biochar combined with AMF resulted in an increase in agronomic responses compared to untreated plants (Bl- –AMF) such as root biomass (+15%), stem diameter (+12%), plant height (+5%) and head diameter (+15%). Seed protein was higher in +AMF than –AMF (on average 20.7 vs 17.2 g m–2, respectively) and in Bh and Bm compared with Bl (on average 19.4 vs 18.2 g m–2, respectively). The oil content of seeds was affected by biochar application and AMF inoculation, especially under 50MAW and 30MAW irrigation levels; conversely, no differences were observed under the 10MAW irrigation level. Sunflower yield characteristics were positively correlated to the net photosynthesis rate and negatively affected by hydrogen peroxide and malondialdehyde content. The results showed that the adoption of biochar and AMF may represent as a successful strategy to balance crop productivity in a semi-arid environment. Although further research is required for a better understanding of the irrigation and fertilization schedule, these preliminary results could be extended to other crops which have similar requirements to sunflower. Highlights - The combined effects of biochar and arbuscular mycorrhizal fungi on sunflower are studied. - Biochar application and mycorrhiza inoculation improved plant performance. - Biochar and AMF positively affected the net photosynthesis rate of sunflower plants. - The adoption of biochar and AMF may mitigate the effect of drought conditions. - Biochar and AMF can support sunflower cultivation.

Combined effects of biochar and biogas slurry on soil nitrogen transformation rates and N2O emission in a subtropical poplar plantation

It has been widely accepted that biochar has a great potential of mitigating soil nitrous oxide (N2O) emission. However, the underlying mechanism about how biochar affects nitrogen transformation and the pathways of soil N2O production is under discussion. A 15N-tracer incubation experiment was conducted to investigate the short-term effects of biochar on soil N transformation rates and source partitioning of N2O emissions in soils from a poplar plantation system. A two-factor experimental design was adopted using biogas digestate slurry and biochar as soil amendments. In total, there were 12 treatments, including three rates of biochar: B0 (control), B2 (80 t ha−1), and B3 (120 t ha−1), and four rates of biogas digestate slurry: C (0 m3 ha−1), L (125 m3 ha−1), M (250 m3 ha−1), and H (375 m3 ha−1). We observed significantly lower rates of net nitrification (Nn) and mineralization (Mn) in biochar-treated soils. The 15N tracer analysis revealed a significant decrease in gross autotrophic (ONH4), heterotrophic nitrification (ONrec), and mineralization (MNorg) rates while an increase in gross immobilization (INH4 and INO3) rates in biochar amended soils. When biogas slurry was applied, biochar only significantly reduced ONH4 except in the moderate slurry treatment. Regardless of the slurry application, biochar consistently suppressed N2O emission by 58–89 %, and nitrification was the dominant pathway accounting contributing >90 % to cumulative N2O emissions. Moreover, soil cumulative N2O emissions significantly negatively correlated with soil ammonium contents and positively with MNorg, Mn, and Nn, showing that biochar decreased N2O emission via a reducing effect on nitrification rates and associated N2O emissions. Our results also highlight that application of N fertilizer greatly influence the biochar's impacts on soil N transformation rates and N2O emission, calling for further studies on their interactions to develop mitigate options and to improve N use efficiency.

Effect of biochar and nitrogen on soil characteristics, growth and yield of radish (Raphanus sativus L.) at Paklihawa, Rupandehi condition of Nepal

An experiment on effect of biochar and nitrogen on soil characteristics, growth and yield of radish (Raphanus sativus L.) was conducted at Institute of Agriculture and Animal Science (IAAS), Paklihawa, Rupandehi, from November 2019 to February 2020. The experiment was laid in Randomized Complete Block Design with two factors: nitrogen and biochar, each factor having four levels (biochar: 0 t/ha, 5 t/ha, 10 t/ha and 15 t/ha and nitrogen: 0 kg/ha, 50 kg/ha, 100 kg/ha, 200 kg/ha), resulting in sixteen treatment combinations. Biochar application was found to be effective in improving soil bulk density, pH, soil organic matter and soil nitrogen and potassium content. Application of nitrogen fertilizer (200 kg/ha) and biochar (15 t/ha) alone, and in combination, showed significantly higher root dry matter (15.83 gm, 16.63 gm and 20.57 gm), biological yield (80 t/ha, 63.75 t/ha, and 95.75) and root yield (26.74 t/ha, 24.06 t/ha and 30.32 t/ha). In comparison to the sole effects of the highest dose of nitrogen fertilizer (200 kg/ha) and the highest dose of biochar (15 t/ha), their combined application showed the increased yield in radish root by 13.38% and 26.01%, respectively, indicating that the combined effect of biochar and nitrogen is more productive for the growth and yield in radish crop as compared to the sole effect of nitrogen and biochar.

Combined effect of biochar and soil moisture on soil chemical properties and microbial community composition in microplastic‐contaminated agricultural soil

AbstractAccumulation of microplastics (MPs) in agricultural environments has caused growing concern in recent years because of its detrimental impacts on soil quality, crop productivity and ecosystem function. This study was conducted to assess the impact of biochar on soil chemical and microbial properties in a MP‐contaminated soil under two moisture regimes. Soil was contaminated with 1% (w/w) of low‐density polyethylene MPs. Four types of standard biochar, that is, oil seed rape (OSR) biochar produced at 550°C (OSR 550) and 700°C (OSR 700) and soft wood pellet (SWP) biochar produced at 550°C (SWP 550) and 700°C (SWP 700), were applied at a rate of 5% (w/w). The control was maintained without MP addition. The samples were incubated in soil with two moisture regimes, that is, at 30% and 70% of the water holding capacity, and the soil chemical and microbiological properties were assessed after 100 days of incubation. OSR biochar application significantly increased soil pH (8.53–8.81) and electrical conductivity (0.51–0.58 dS/m) in both moisture regimes. The effect of biochar application on soil enzyme activity and microbial community composition did not show a clear trend. However, SWP 700 biochar improved soil enzyme activity compared with that of the control and improved bacterial diversity and evenness compared with those of other biochars, which was attributed to the high surface area available for microbial colonization. Low soil moisture content significantly reduced enzyme activity and bacterial richness even with biochar amendment, except for SWP 550 biochar. This study implies the suitability of biochar for improvement of soil quality in MP contaminated soil under both moisture regimes. However, further long‐term studies are needed to get a clear understanding on the impact of different types of biochar on MP‐contaminated soil.

Alleviation of Cd stress in maize by compost mixed biochar

Cadmium (Cd) is a heavy metal that neutrally occurs in soil. It is carcinogenic in humans and caused a significant decline in the plant’s growth when up has taken beyond the threshold limit. The fertilizers, manure, sewage sludge, and aerial deposition are the main source of cadmium contamination in soil. Furthermore, poor soil organic matter is also one of the allied factors which facilitate the development of Cd toxicity in soil. The decomposition resistance nature of biochar makes it an effective amendment for cadmium remediation. Through crop production, Cd enters the food system. Individual studies on biochar and compost are found in the literature but the combined effect of biochar and compost are rarely documented especially in maize crops. The current pot study was conducted in Pesticide Quality Control Laboratory, Multan, Pakistan. However, the current study was novel and conducted by using compost mixed biochar (CB) against Cd toxicity in maize. Four application rates of CB i.e., 0, 0.50, 0.75 and 1.00% (1.00CB) were applied under 3 levels of Cd i.e., 0 (0Cd), 2.5 (2.5Cd) and 5 mg Cd kg−1 soil (5.0Cd). Overall, results indicated that 1.00%CB remained significantly best at higher 5.0Cd for improvement in soil organic matter, plant height, root length, number of leaves, leaves fresh and dry weight, plant fresh and dry weight, chlorophyll a, b, total and carotenoids. A significant decrease in soil pHs, leaves anthocyanin and lycopene also validated the efficacious functioning of 1.00%CB over control in 2.5 and 5.0Cd. In conclusion, the use of 1.00%CB is a better approach to decrease Cd harmful effects to improve gas exchange attributes, growth and chlorophyll contents in maize. Long-term research is required on co-composted biochar toward mitigation of cadmium toxicity under different geographical locations.

Grain yield, plant nitrogen content and nitrogen use efficiency as affected by controlled-release urea and straw biochar in a rice field

Resulting from the positive effect on rice productivity, the application of biochar and controlled-release urea in the form of polymer-coated urea (PCU) in crop production attracts more and more interest. However, field studies considering the combined effect of biochar and PCU are rare. This 2-year study examined the combined effects of biochar and PCU on yield, yield components, plant height, plant nitrogen concentration and nitrogen recovery efficiency in a waterlogged rice field. Experimental treatments combined two biochar rates (0 and 2800 kg ha−1) and three nitrogen rates (0, 120 and 180 kg N ha−1). The results showed a yield decrease under biochar application without nitrogen fertilizer. The application of 120 kg N ha−1 PCU and biochar had the highest yield in 2017. No significant differences of grain yields were indicated between 120 and 180 kg N ha−1. High grain yield and nitrogen use efficiency was obtained with 120 kg N ha−1 PCU. Therefore, 120 kg N ha−1 PCU can be recommended for rice production in this area.