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Biochar enhances nut quality of Torreya grandis and soil fertility under simulated nitrogen deposition
Abstract
Torreya grandis, an economically important nut tree in Southeast China, is being subjected to increasing atmospheric nitrogen (N) deposition, and thus far its impact on nut quality remains unknown. Also, studies evaluating nut quality response to biochar application (commonly used as soil amendment) to soils under N deposition conditions are rare. Here, we investigated changes of nut physical characteristics (i.e., nut weight, length and width and kernel weight) and nut nutritional components (i.e., lipid, protein, starch and total soluble sugars) under a factorial combination of biochar application (0, 20 t ha⁻¹) and simulated additional nitrogen deposition (0, 30 and 60 kg N ha⁻¹ yr⁻¹) treatments in a growing season (approximately 7 months). Results showed that N addition had a direct fertilizing effect, with a significant increase of nut weight, nut size, kernel weight, and nut nutritional components in terms of lipid, protein, starch and total soluble sugars. However, soil chemical properties were negatively affected by N addition with significant decreases in soil pH and available N, P and K. Biochar application showed a liming effect, with a significant increase of soil pH which was significantly correlated with nut weight and the main nut nutritional components. Additionally, biochar strongly interacted with additional N deposition by increasing the availability of N, P and K in soil. Our study suggested, for the first time, that the ‘win-win’ can be achieved, both nut quality of T. grandis and soil fertility can be improved by biochar application to soils suffering from N deposition. Results are relevant for the successful improvement of nut crop quality and development of sustainable agriculture under accelerated N deposition worldwide.
... Biochar can be made from any organic feedstock material such as woody residues, and could then be returned to the surface organic horizons [19][20][21]. Biochar has been used on forest [22,23] range [24], mine reclamation [25], and agricultural [20,[26][27][28][29] soils as a method of improving greenhouse gas emissions [23,30], sequestering carbon [21] and improving soil properties [27][28][29]31,32]. Biochar may contribute to reducing plant herbivory by insect pests, either through physical contact with the material, or by improving overall plant resistance to herbivory. ...
... Biochar can be made from any organic feedstock material such as woody residues, and could then be returned to the surface organic horizons [19][20][21]. Biochar has been used on forest [22,23] range [24], mine reclamation [25], and agricultural [20,[26][27][28][29] soils as a method of improving greenhouse gas emissions [23,30], sequestering carbon [21] and improving soil properties [27][28][29]31,32]. Biochar may contribute to reducing plant herbivory by insect pests, either through physical contact with the material, or by improving overall plant resistance to herbivory. ...
... Biochar material made from woody residues and applied as a soil amendment has been shown to improve soil health indices and is becoming a tool to sequester carbon on forest [22,23], range [24], mine reclamation [25], and agricultural sites [20,[26][27][28][29]. In the laboratory, biochar can have a deleterious effect on survival [35] as well as development and fecundity [36] of insects that are directly exposed to the material in enclosed arenas. ...
The use of biochar as a soil amendment in forest ecosystems can be beneficial in the restoration of degraded soils. Forest insects such as the Douglas-fir tussock moth, Orgyia pseudotsugata (McDonnough) (Lepidoptera: Erebidae), may be exposed to biochar when the material is applied. Two experiments were conducted using biochar either (1) applied to the surface of the diet at three rates (0, 5, and 10 mg) or (2) incorporated into synthetic diet at four rates (0, 10, 20, and 40% volume/volume). The objective of both experiments was to determine if biochar on the surface or incorporated into a synthetic diet affected development and survival of O. pseudotsugata larvae. In both experiments, there was a significant decrease in estimated time to larval mortality in all biochar treatments compared to untreated controls. In the surface-applied biochar experiment, there was a significant difference in larval weight gain at day 12 between the control and 10 mg biochar treatments. In the experiment with biochar incorporated into the diet, mean larval weight at day 12 was highest in the low (10%) biochar treatment compared to all other treatments, although weight gain was only significantly different between the low- and high-concentration (40%) biochar treatments. Our results suggest that larvae, feeding on a low amount of biochar in the synthetic diet, may respond by engaging in compensatory feeding behavior. Fewer surviving larvae in the biochar treatment groups may contribute to the lack of significance found in the comparison of weight gain at day 24 in each experiment.
... Adding BC to the soil also increases mineralization and/or ammonia oxidation in the soil (Dempster et al. 2011;Maestrini et al. 2014). Soil acidification caused by the settling of atmospheric nitrogen via the introduction of anions and H + will lead to increased availability of toxic cations such as aluminium, iron, etc. (Bowman et al. 2008;Phoenix et al. 2012;Zhang et al. 2017). Nonetheless, such soil toxicity can be overcome by BC amendment due to its alkalinity and high CEC, which counteracts reduced uptake of trace elements in plants (Rizwan et al. 2016). ...
... To date, the studies of the benefits of BC amendment with simulated nitrogen deposition have mainly focused on agricultural crops, such as corn (Bornø et al. 2018) and rice (Makino et al. 2000), while study of tree species' growth is still lacking (Currie and Nadelhoffer 1999;Glaser et al. 2002). Zhang et al. (2017) revealed that, aided by BC amendment, the nut quality and soil fertility of Torreya grandis, a conifer belonging to the Taxaceae family, could be improved with simulated nitrogen deposition. Studies on the interaction of dicotyledon species with soil amendment by BC modification and simulated nitrogen deposition remain rare. ...
... The crude BC material was ground and screened through a 2-mm sieve to obtain particles in high consistency. The final physicochemical properties of the BC material were: pH: 9.80; bulk density: 0.5 g cm −3 ; specific surface area: 9.7 m 2 g −1 ; CEC: 189.3 cmol kg −1 ; organic carbon: 425 g kg −1 ; total N: 5.2 g kg −1 ; total P: 3.4 g kg −1 ; ash: 18.6 % (Zhang et al. 2017). The nitrogen deposition was simulated by dissolving ammonium nitrate (NH 4 NO 3 ) in water and spraying it on leaves and soil. ...
This work investigated the effective doses of biochar (BC) amendment with simulated nitrogen deposition on the stimulation of pecan (Carya illinoinensis) growth. A total of nine conditions combining three levels of BC-BC0, 0 t ha-1 year-1; BC20, 20 t ha-1 year-1; and BC40, 40 t ha-1 year-1-and three levels of simulated nitrogen deposition-N0, 0 kg N ha-1 year-1; N50, 50 kg N ha-1 year-1; and N150, 150 kg N ha-1 year-1-were applied throughout 1 year on the pecan-grafted seedlings of cultivar 'Pawnee'. The growth, photosynthesis, chlorophyll and nutrient content in the seedlings were measured. The soil bulk density, pH, nitrogen content and enzymatic activities were also measured. Biochar amendment reduced soil bulk density and elevated soil pH. Meanwhile, aided by BC amendment, the inorganic nitrogen content and enzyme activities increased with increasing doses of nitrogen. In the absence of BC amendment, the seedlings' height, photosynthesis and chlorophyll pigments were only stimulated by a low level of simulated nitrogen deposition (N50), whereas a high level of simulated nitrogen deposition (N150) impeded the growth. The seedlings improved the most under the combined treatment of BC20N150, wherein the seedling heights, photosynthesis and total chlorophyll improved by 22 %, 70 % and 40 %, respectively, compared to those treated solely with BC20. Further increase of nitrogen retention in the soil by the BC40 did not further improve the growth of the seedlings, suggesting the possible mechanisms involve nutrient uptake and usage dynamic in the seedlings. The BC amendment alleviated the antagonist effect from simulated nitrogen deposition that suppressed the absorption of phosphorus, potassium and iron. The effect of applying both BC amendment and simulated nitrogen deposition to the growth of seedlings was additive at fertilizing tree species.
... For example, application of nutrient-rich biochar directly improve the soil nutrient level, whereas in some cases biochar improve the soil nutrient availability indirectly by improving soil physicochemical properties ( Fig. 3) such as water-holding capacity (WHC), soil porosity, water infiltration, pH, CEC, SOM level, etc. (Kuppusamy et al. 2016;El-Naggar et al. 2019;Panahi et al. 2020). Improvement in soil properties after biochar application resulted in enhanced crop production (Laghari et al. 2015;Zhang et al. 2017a). However, the impact of biochar amendment to soil properties and crop productivity mainly depends on biochar properties (e.g., pH, CEC, and C/N ratio) and its production conditions (e.g., raw material, pyrolysis temperature and other modifications), soil type and conditions, crop plant species, and management practices (Zhang et al. 2017a;Singh et al. 2019;Dai et al. 2020;Leng et al. 2021). ...
... Improvement in soil properties after biochar application resulted in enhanced crop production (Laghari et al. 2015;Zhang et al. 2017a). However, the impact of biochar amendment to soil properties and crop productivity mainly depends on biochar properties (e.g., pH, CEC, and C/N ratio) and its production conditions (e.g., raw material, pyrolysis temperature and other modifications), soil type and conditions, crop plant species, and management practices (Zhang et al. 2017a;Singh et al. 2019;Dai et al. 2020;Leng et al. 2021). For example, biochar derived from lignocellulosic biomass has better pore structure and help in improving soil hydrophysical properties after application , whereas biochar derived from nutrient-rich manure are more beneficial for improving nutrient content and crop productivity in low fertility soils (Jeffery et al. 2017;Dai et al. 2020). ...
Biochar, a heterogeneous carbonaceous material, has multifaceted application potential for environmental management. Biochar has been commonly used for contaminant removal from soil and water systems, soil quality improvement, soil C-sequestration, inoculant carrier, etc. Surface area, pore space, surface functional groups, pH, cation exchange capacity (CEC), and nutrient contents are a few key properties that determine the potential of biochar application. Raw materials and pyrolysis conditions are the determining factors for these aforesaid properties of biochar. Biochar production from lignocellulosic biomass and biosolids at moderate pyrolysis temperatures (350–600 °C) are commonly recommended for waste management. Despite its multifaceted application potential, biochar utilization at widescale is limited due to certain incompatibilities with the environmental systems. To overcome the incompatibilities between biochar properties and environmental conditions, engineering of biochar by using different additives and modifications in pyrolysis conditions are getting wider attention nowadays. In this chapter, we have explored the potential of engineered biochar as soil fertilizer. A bibliometric analysis was performed to collate the literature and to see the research trend of engineered biochar as soil fertilizer. Studies reported that engineering of biochar leads to improvement in its surface and physicochemical properties. Engineered biochar with improved properties helps in enhancing soil physicochemical, nutrient, and biological properties after amelioration. Improvement in soil properties showed better crop productivity in some pot/laboratory experiments. Overall, we observed that the research on exploring engineered biochar as soil fertilizer is comparatively limited as compared to its exploration as contaminant adsorbent and source of energy production.
... The energy conversion of the input electric energy to heat by microwave heating is typically in the range of 20-60% (Yao et al. 2014;Sun et al. 2016;Rosa et al. 2017). Moreover, the energy loss in the transformer and the magnetron during microwaveassisted pyrolysis of biomass is approximately 26%, and the power loss caused by the heat loss is approximately 29% (Xiqiang et al. 2014;Zhang et al. 2017a). ...
... For example, application of nutrient-rich biochar directly improve the soil nutrient level, whereas in some cases biochar improve the soil nutrient availability indirectly by improving soil physicochemical properties (Fig. 3) such as water-holding capacity (WHC), soil porosity, water infiltration, pH, CEC, SOM level, etc. (Kuppusamy et al. 2016;El-Naggar et al. 2019;. Improvement in soil properties after biochar application resulted in enhanced crop production (Laghari et al. 2015;Zhang et al. 2017a). However, the impact of biochar amendment to soil properties and crop productivity mainly depends on biochar properties (e.g., pH, CEC, and C/N ratio) and its production conditions (e.g., raw material, pyrolysis temperature and other modifications), soil type and conditions, crop plant species, and management practices Singh et al. 2019;Dai et al. 2020;. ...
The expanding demand for environmental treatment increasingly requires different types of engineered char with high performance. In this context, new trends in pyrolysis methods have emerged and contributed to the sustainable development of pyrolysis technologies, namely microwave-assisted pyrolysis, co-pyrolysis, pyrolysis under non-inert ambiances, hydrothermal carbonization (wet pyrolysis), and integrated pyrolysis techniques. The outstanding advantages of these technologies over conventional pyrolysis include: increase in biomass conversion efficiency of the process, use of nonconventional raw material, increase in adsorption capacity of biochar by enhanced activated oxygen species, porosity, and functional groups, and removal or immobility of contaminants. The biochar products can be widely applied in various environmental fields, such as carbon capture and sequestration, soil amendment, adsorption of contaminants in soil, water, and air, and energy production. Nevertheless, challenges remain for these new trends, such as the increase in cost for the installation and operation, the lack of knowledge of the mechanism involved during pyrolysis, the difficulty in scaling up, etc. Further studies are recommended to facilitate the application of these new trends, such as pilot tests or field experiments to evaluate the real effects of biochar products prior to large-scale applications or their long-term risk during use, or prediction of properties of biochar and their impacts on environmental applications using modeling or machine learning approaches.KeywordsAdvantagesBiocharLimitationNew trendsOpportunitiesPyrolysis
... The energy conversion of the input electric energy to heat by microwave heating is typically in the range of 20-60% (Yao et al. 2014;Sun et al. 2016;Rosa et al. 2017). Moreover, the energy loss in the transformer and the magnetron during microwaveassisted pyrolysis of biomass is approximately 26%, and the power loss caused by the heat loss is approximately 29% (Xiqiang et al. 2014;Zhang et al. 2017a). ...
... For example, application of nutrient-rich biochar directly improve the soil nutrient level, whereas in some cases biochar improve the soil nutrient availability indirectly by improving soil physicochemical properties (Fig. 3) such as water-holding capacity (WHC), soil porosity, water infiltration, pH, CEC, SOM level, etc. (Kuppusamy et al. 2016;El-Naggar et al. 2019;. Improvement in soil properties after biochar application resulted in enhanced crop production (Laghari et al. 2015;Zhang et al. 2017a). However, the impact of biochar amendment to soil properties and crop productivity mainly depends on biochar properties (e.g., pH, CEC, and C/N ratio) and its production conditions (e.g., raw material, pyrolysis temperature and other modifications), soil type and conditions, crop plant species, and management practices Singh et al. 2019;Dai et al. 2020;. ...
Biochar is a prominent adsorbent for environmental remediation. The physicochemical properties responsible for adsorption can be significantly enhanced by using physical, chemical, and biological treatments of biochar. The biological treatment methods are advantageous in terms of cost-effectiveness and reduced secondary pollutants. The present chapter summarizes the need, methodology, modification mechanism of biological modification of biochar, and its implementation for environmental remediation. The biologically modified biochar can be obtained by either ex situ (pyrolysis of anaerobically digested residue) or in situ (using extracellular enzymes) technologies. The process includes colonization and biofilm formation by microorganisms on biochar surface and attachment of microbes. Biologically modified biochar metabolizes organic/inorganic contaminants and helps in adsorption, biodegradation, and bio-adsorption simultaneously.
... Soil amendment with biochar was recommended in particular for reducing nutrient leaching losses in areas with high rainfall as reported by Major (2009). Phosphorous in plant wastes can also conserved and released through the addition of certain types of biochar in plant-available forms (Zhang et al., 2017). ...
... Biochar is a substance having the capacity to retain macronutrients directly, such as N (Yue, 2017;Zhang et al., 2017). This can be attributed to the nutrient content of biochar itself (Glaser, 2002). ...
Biochar is the solid, carbon-rich material obtained by pyrolysis using different biomasses. The application of biochar to agricultural soils has the potential to greatly improve soil physical, chemical and biological conditions. It has been widely documented in previous studies that, crop growth and yield can be increased by using biochar. This review exclusively aimed to summarizes comprehensive review papers or research findings and own preliminary results on the role of biochar in plant nutrients availability and nutrient retentions of agricultural soil based on biochar effects on plant-available nutrients, biochar nutrient contents and its contribution to the soil, nutrient retention, cation exchange capacity and liming effects of biochar within the soil solution. It has been widely documented in previous studies that, biochar application to the agricultural soil has imperative effects on crop growth and yield can be increased by using biochar application on plant-available nutrients, nutrient contents and its contribution to the soil, nutrient retention, cation exchange capacity and liming effects of biochar within the soil solution.
... Soil amendment with biochar was recommended in particular for reducing nutrient leaching losses in areas with high rainfall as reported by Major (2009). Phosphorous in plant wastes can also conserved and released through the addition of certain types of biochar in plant available forms (Zhang et al., 2017). The high nutrient holding capacity of biochar makes it suitable to charge with organic waste nutrients such as compost, manure, or animal/human urine, which might be a freely available fertilizer to small coffee farmers (Domingues and Rimena R, 2017). ...
... Biochar incorporation can alter soil physical properties such as structure, pore size and its distribution density, that affect the soil aeration, water holding capacity, soil workability and at the final plant growth, (Downie et al., 2009). Biochar is a substance having the capacity to retain macronutrients directly, such as N (Yue, 2017;Zhang, 2017). This can be attributed to the nutrient content of biochar itself (Glaser, 2002). ...
Biochar is the solid, carbon-rich material obtained by pyrolysis using different biomasses. The application of biochar to agricultural soils has the potential to greatly improve soil physical, chemical and biological conditions. It has been widely documented in previous studies that, the crop growth and yield can be increased by using biochar. This review exclusively aimed to summarizes a comprehensive review papers or research findings and own preliminary results on the role of biochar in plant nutrients availability and nutrient retentions of agricultural soil basically based on biochar effects on plant available nutrients, biochar nutrient contents and its contribution to the soil, nutrient retention, cation exchange capacity and liming effects of biochar within the soil solution. It has been widely documented in previous studies that, biochar application to the agricultural soil has imperative effects on the crop growth and yield can be increased by using biochar application on plant available nutrients, nutrient contents and its contribution to the soil, nutrient retention, cation exchange capacity and liming effects of biochar within the soil solution.
... For example, low pyrolysis temperature biochar has been reported to contain a larger amount of nonpyrolyzed organic residue and organic nutrients than high-temperature biochar (Wang et al., 2017a, b;Zhu et al., 2017a, b). In addition, Zhang et al. (2017) noted that the higher organic-C and total-N of nutrients in low pyrolysis temperature biochar facilitate the formation of soil macroaggregates which are more favourable for microbiota diversity and growth. Few elements in biochar (minerals, volatile organic compounds, free radicals, ash) however, have been reported to probably affect microbial activity, influence soil microbial community and alter soil enzyme activity that significantly played a role in various biogeochemical cycles (Spokas et al., 2011;Zhu et al., 2017a, b) but, this requires further research. ...
... Recently, Thies and Rillig (2009) reported that soil microbiota (bacteria, fungi, actinomycetes, and arbuscular mycorrhizal fungi) could preferentially colonize biochar depending on its characteristics. Notable differences in bacterial and fungal community structures have been observed in the soil after the biochar applications (Abujabhah, 2017;Zhang et al., 2017) suggesting that it is the interaction between biochar and the soil microbiota that may cause positive effects on yield and not just biochar only. Microbial diversity, however, varies and is dependent on the soil type, soil properties and other climatic conditions. ...
Biochar–soil microbiota interactions may occur within a short or long
period of time after application, and the behaviour of biochar could determine their
impacts on soil. In comparison, modifications in soil microbiota function, structure,
biomass and/or ecosystemic function following biochar application could translate
to changes in soil fertility leading to positive and/or negative impacts. Amendment
of soil with biochar has been evaluated globally as a means of improving soil health,
fertility and increase soil microbial biomass. However, little is known about the
mechanisms through which biochar modulates soil microbial activity or implications
of these interactions. This review unravels possible interactions that may occur
during soil–biochar contact time and the impacts on soil microbial function.
Furthermore, the paper discusses interactions between biochar and microbial groups
(such as bacteria, fungi, nematode, archaea, enzymatic activities), and elucidates
possible factors that may influence biochar–microbiota behaviour in the soil environment.
It also considers the implications for the associated biota and feasibility of
applying biochar in weathered soils and/or contaminated land remediation. Finally,
the review highlights knowledge gaps and future research directions.
... For example, low pyrolysis temperature biochar has been reported to contain a larger amount of nonpyrolyzed organic residue and organic nutrients than high-temperature biochar (Wang et al., 2017a, b;Zhu et al., 2017a, b). In addition, Zhang et al. (2017) noted that the higher organic-C and total-N of nutrients in low pyrolysis temperature biochar facilitate the formation of soil macroaggregates which are more favourable for microbiota diversity and growth. Few elements in biochar (minerals, volatile organic compounds, free radicals, ash) however, have been reported to probably affect microbial activity, influence soil microbial community and alter soil enzyme activity that significantly played a role in various biogeochemical cycles (Spokas et al., 2011;Zhu et al., 2017a, b) but, this requires further research. ...
... Recently, Thies and Rillig (2009) reported that soil microbiota (bacteria, fungi, actinomycetes, and arbuscular mycorrhizal fungi) could preferentially colonize biochar depending on its characteristics. Notable differences in bacterial and fungal community structures have been observed in the soil after the biochar applications (Abujabhah, 2017;Zhang et al., 2017) suggesting that it is the interaction between biochar and the soil microbiota that may cause positive effects on yield and not just biochar only. Microbial diversity, however, varies and is dependent on the soil type, soil properties and other climatic conditions. ...
Biochar–soil microbiota interactions may occur within a short or long period of time after application, and the behaviour of biochar could determine their impacts on soil. In comparison, modifications in soil microbiota function, structure, biomass and/or ecosystemic function following biochar application could translate to changes in soil fertility leading to positive and/or negative impacts. Amendment of soil with biochar has been evaluated globally as a means of improving soil health, fertility and increase soil microbial biomass. However, little is known about the mechanisms through which biochar modulates soil microbial activity or implications of these interactions. This review unravels possible interactions that may occur during soil–biochar contact time and the impacts on soil microbial function. Furthermore, the paper discusses interactions between biochar and microbial groups (such as bacteria, fungi, nematode, archaea, enzymatic activities), and elucidates possible factors that may influence biochar–microbiota behaviour in the soil environment. It also considers the implications for the associated biota and feasibility of applying biochar in weathered soils and/or contaminated land remediation. Finally, the review highlights knowledge gaps and future research directions.
... Soil amendment with biochar was recommended in particular for reducing nutrient leaching losses in areas with high rainfall as reported by Major (2009). Phosphorous in plant wastes can also conserved and released through the addition of certain types of biochar in plant-available forms (Zhang et al., 2017). ...
... Biochar is a substance having the capacity to retain macronutrients directly, such as N (Yue, 2017;Zhang et al., 2017). This can be attributed to the nutrient content of biochar itself (Glaser, 2002). ...
Biochar is the solid, carbon-rich material obtained by pyrolysis using different biomasses. The application of biochar to agricultural soils has the potential to greatly improve soil physical, chemical and biological conditions. It has been widely documented in previous studies that, crop growth and yield can be increased by using biochar. This review exclusively aimed to summarizes comprehensive review papers or research findings and own preliminary results on the role of biochar in plant nutrients availability and nutrient retentions of agricultural soil based on biochar effects on plant-available nutrients, biochar nutrient contents and its contribution to the soil, nutrient retention, cation exchange capacity and liming effects of biochar within the soil solution. It has been widely documented in previous studies that, biochar application to the agricultural soil has imperative effects on crop growth and yield can be increased by using biochar application on plant-available nutrients, nutrient contents and its contribution to the soil, nutrient retention, cation exchange capacity and liming effects of biochar within the soil solution.
... Biochar is a by-product derived from the pyrolysis of biomasses, having properties suitable for environmental applications . While biochar has been reported to enhance N retention (Pan et al., 2017;Zhang et al., 2017), contrary reports have shown that it did not affect soil inorganic N retention or losses (Foster et al., 2016;Ramlow et al., 2019). It has also been reported to accelerate soil nitrification (Hale et al., 2013;Song et al., 2013). ...
... There was continuous hydrolysis of NH 4 + in PM treatment while the opposite was observed in PMB. This indicates the sorption ability of biochar for N. The sorption of NH 4 + after biochar application has been previously reported (Pan et al., 2017;Zhang et al., 2017;Ibrahim et al., 2020). In manured soils, the application of PDBB and PDCB led to an increase in NH 4 + -N retention of 34.5% and 6.8% ...
Enhancing soil N retention is important to mitigate the negative environmental impacts caused by the loss of applied N fertilizers. Therefore, the use of modified biochar in the soil is a novel approach to enhance the sorption of N ions. Biochars derived from bamboo, cow, and pig manures were de-ashed and their properties were characterized. The de-ashed biochars were comparatively assessed with raw biochars on N-retention, and how this process is regulated by microbial activities, diversity, and abundance in a manured soil. De-ashing increased the intensity of biochar functional groups and their surface structure. In manured soils, the application of de-ashed bamboo biochar (PDBB) and de-ashed cow manure biochar (PDCB) led to an increase in NH4+-N retention of 34.5% and 6.8% relative to the amendment with raw biochars. Similarly, increased retention of 20.9%, 14.8%, and 19.1% of NO3−-N, and an increase of 21.1%, 11.1% and 11.5% in total N were observed in PDBB, PDCB and de-ashed pig manure biochar (PDPB) respectively, compared to their raw biochars after 8 weeks. The modified surface properties of de-ashed biochars led to higher bacterial colonization, with an increase in the diversity and relative abundance of bacterial 16S rRNA genes, compared to the raw biochar treatments. This spike in microbial groups stimulated protease activities and hence, an increased abundance of N-cycling organisms. The increased microbial abundance was associated with a reduction in the release of urease by these microbial groups for the hydrolysis of urea, thereby ensuring soil N retention. De-ashing increased the intensity of biochar functional groups and improved its surface properties, which resulted in increased N-sorption, and immobilization by stimulating microbial activities and diversity in soil.
... The higher NH 4 + retention in the raw biochars than in their modified forms was because raw biochar possesses a net negative charge on its surfaces with a higher affinity for cations (Clough et al., 2013;Ibrahim et al., 2023). Hence, the sorption of NH 4 + after biochar application has been frequently reported (Pan et al., 2017;Zhang et al., 2017). Similar to our observations, Li et al. (2017) showed that MgO-modified biochars exhibit a stronger affinity for NO 3 − and PO 3 − anions than NH 4 + cations, even though their NH 4 + adsorption capacity remained acceptable. ...
Mitigating the loss and negative impacts of reactive N from fertilized soils remains a global environmental challenge. To optimize N retention by biochar, bamboo and pig manure biochars were modified as MgO- and sepiolite-biochar composites and characterized. Novel soil application of the modified biochars and their raw forms were comparatively evaluated for N-retention in a fertilized soil leached for 90 days in a column experiment. Changes in N-cycling-related enzyme and bacterial structure were also reported after 90 days. Results revealed low leaching losses of NH4+, which reduced over time across all the treatments. However, while sole fertilizer (F) increased the initial and cumulative NO3− leached from the soil, the MgO-bamboo biochar (MgOBF) and sepiolite-bamboo biochar (SBF) treatments reduced leachate NO3− by 22.1 % and 10.5 % compared to raw bamboo biochar (BBF) treatment. However, 15.5 % more NO3− was leached from the MgO-pig manure biochar-treated soil (MgOPF) compared to its raw biochar treatment (PMBF) after 90 days. Dissolved organic N leached was reduced by 9.2 % and 0.5 % in MgOBF and SBF, as well as 15.4 % and 40.5 % in MgOPF and SPF compared to their respective raw forms. The total N of the biochars, adjustment of surface charges, cation exchange capacity, surface area, pore filling effects, and the formation of potential Mg-N precipitates on the modified-biochar surfaces regulated N leaching/retention. In addition, the modified biochar treatments reduced the hydrolysis of urea and stimulated some nitrate-reduction-related bacteria crucial for NO3− retention. Hence, unlike the raw biochar and MgOPF treatments, MgOBF, SBF, and SPF hold promise in mitigating inorganic-N losses from fertilized soils while improving the soil's chemical properties.
... Biochar can not only potentially affect soil carbon sequestration but also the modification of its physicochemical and biological aspects [19,20]. As previously stated, the type of biomass material employed for biochar generation, as well as the various processes and conditions under which it is produced, can result in a variety of qualities. ...
This review comprehensively examines biochar, an essential material in an era of climate change for reducing carbon dioxide (CO2) emissions into the atmosphere. It is inconspicuous, black, lightweight, and very porous, and is produced through the thermal conversion of biomass. Our literature review highlights biochar’s expansive application possibilities. Firstly, its potential to improve soil quality and sequester CO2 has been examined, as well as its utilization in iron and steel manufacturing to minimize the quantity of coke and ultimately reduce CO2 emissions. In industrial manufacturing, the complete elimination of coke can promote environmental neutrality, which is achieved using biochar from biomass for its extrusion. Furthermore, biochar is becoming increasingly significant in modern energy storage technologies and as an important additive in Pickering emulsions, which are also employed in energy storage systems. Additionally, the use of carbon black is a broad topic, and this review illustrates where it can be successfully utilized, especially in environmentally sensitive areas.
... Biochar can change soil pH, depending on the soil type or biochar applied to the soil. Application of alkaline biochar to acid soils can increase soil pH and affect bioavailability [10], [11], [12]. Since most biochar is alkaline, the addition of biochar to alkaline soils usually has little effect. ...
This study aims to determine the effect of young coconut waste biochar and goat manure application on the chemical properties of the entisol. The Biochar Research Station, Universitas Syiah Kuala, conducted the research. This study used a factorial randomized block design consisting of two factors. The first factor was the dose of young coconut waste biochar (0, 5, and 10 t ha ⁻¹ ), and the second was the dose of goat manure (0, 5, 10, and 15 t ha ⁻¹ ). Parameters observed in this study were soil chemical properties analysis of entisol (pH, organic C, total N, available P, and exchangeable K). The results showed that the young coconut waste biochar application could affect the soil’s chemical properties, especially the soil exchangeable K. Young coconut waste biochar application can increase the exchangeable soil K in tomato cultivation land. The application of goat manure did not affect the soil’s chemical properties in tomato cultivation land.
... The application of EBCs to soil usually changes the circulation, retention, and transformation of nitrogen, which improves the utilization of nitrogen and reduces the leaching loss of nitrogen in soil (Pan et al., 2017;Zhang et al., 2017). Generally, acid-activated biochar is often closely associated with soil nitrogen cycling. ...
Biochar can be effectively used in soil amendment, environmental remediation as well as carbon sequestration. However, some inherent characteristics of pristine biochars (PBCs) may limit their environmental applications. To improve the physicochemical properties of PBCs and their effects on soil amendment and pollution remediation, appropriate modification methods are needed. Engineered biochars (EBCs) inevitably have a series of effects on soil physicochemical properties and soil biota after being applied to the soil. Currently, most studies focus on the effects of PBCs on soil physicochemical properties and their amendment and remediation effects, while relatively limited studies are available on the impacts of EBCs on soil properties and biota communities. Due to the differences of biochars modified by various methods on soil physicochemical properties and biota communities, the impact mechanisms are different. For a better understanding of the recent advances in the effects of EBCs on soil physicochemical properties and biota communities, a systematic review is highly needed. In this review, the development of EBCs is firstly introduced, and the effects of EBCs on soil physicochemical properties and biota communities are then systematically explored. Finally, the suggestions and perspectives for future research on EBCs are put forward.
... Crop yields have always been a major focus of agricultural research and they cannot be increased without improving the soil environment and crop traits. The application of biochar can increase soil enzyme activity levels [87], soil nutrient supply [88,89], and soil water and fertilizer storage capacity [90,91] to create good soil conditions for crop growth. In addition, the application of biochar can promote crop root growth [92,93], regulate crop metabolic activities [94], and increase the accumulated crop biomass [95]. ...
The ridge–furrow rainwater harvesting (RFRH) planting mode is widely used in arid and semi-arid areas to solve the problems of agricultural water shortage and low productivity. However, the impact of film mulching on the stability of soil carbon pools makes this planting mode vulnerable to the risk of increased soil carbon emissions and carbon pool losses. In order to clarify the relationship between soil carbon emissions and hydrothermal factors, as well as the regulatory effect of biochar application on soil carbon sequestration and reduced emissions under this planting mode, we set up a biochar application experiment. The effects of the biochar application (at 10 Mg ha−1 biochar and 20 Mg ha−1 biochar) on the soil water dynamics, soil temperature changes, CO2-C and CH4-C flux dynamics, grain yield, carbon emission efficiency, and the net ecosystem carbon budget in wheat fields under the RFRH planting mode were investigated, with no biochar application as the control. The results showed that applying biochar increased the soil water content, soil average temperature, cumulative CH4-C uptake, wheat grain yield, and carbon emission efficiency by 3.10–12.23%, 0.98–3.53%, 59.27–106.65%, 3.51–16.42%, and 18.52–61.17%, respectively; reduced the cumulative CO2-C emissions by 7.51–31.07%; and increased the net ecosystem carbon budget by 2.91 Mg C ha−1 to 6.06 Mg C ha−1. The results obtained by equation fitting showed that in wheat fields under RFRH, the CO2-C emission fluxes had negative and positive exponential relationships with the soil water content and soil temperature, respectively, while the CH4-C uptake fluxes had no significant correlation with the soil water content and had an inverse U-shaped quadratic function relationship with soil temperature. Overall, these results suggest that the application of biochar to wheat fields under RFRH can improve grain yield, farmland carbon emission efficiency, and the net ecosystem carbon budget, and change wheat fields from a carbon source to a carbon sink. These results can provide a theoretical basis and technical support for efficient, green, and sustainable production in farmland in arid and semi-arid areas.
... The surface of biochar possesses various functional groups, including hydroxyl, carbonyl and carboxyl (Tan et al. 2015), and their abundance is the most important factor for regulating the sorption-based heavy metal stabilization (Guo et al. 2020). Organic matter in the soil can assist reduction of trace metal availability in the soil solution, which can harm agricultural plant nutrition and growth (Zhang et al. 2017). ...
Almost all of the world’s fertile land is being used to its full capacity. Researchers and policymakers are paying close attention to the restoration and utilization of contaminated land for sustainable agricultural production. Different physical, chemical and biological treatment methods are used for remediation of pollutants. Chemical treatments take less time to remediate contaminated soil by adding organic and inorganic components. Biochar is a pyrolyzed material with a higher surface area, CEC, carbon and nutrient contents. It also helps in increasing the soil carbon-sequestration potential. Due to enhanced surface area, functional groups, mineral content and CEC, it increases the metal adsorption and reduces the labile fractions of heavy metal in soil solution. The impact of biochar in heavy metal dynamics in terms of soil health and plant yield potential is discussed in this chapter.
... Biochar is a substance having the capacity to retain macronutrients directly, such as N (Yue, 2017;Zhang, 2017). This can be attributed to the nutrient content of biochar itself (Glaser, 2002;Shepherd, 2017). ...
... This result is in line with the study of [21] which indicates biochar increased the soil nitrogen content. [22], stated that biochar addition to topsoil leads to a decrease in nitrogen leaching from the soil profile at a higher rate. ...
Abstract
Modern coffee farming is essentially based on the production of quality seedlings with the desirable shoot and root growth mainly determined
by nutrient uptake of the seedlings. Therefore, this study was conducted to evaluate the effects of pot size and biochar-based media composition
on the nutrient uptake of coffee seedlings. The experiment was laid out in a factorial experiment arranged in RCBD with three replications. The
treatment combination included four levels of pot size (P1=7x13cm, P2=10x16cm, P3=13x19cm and P4=16x22cm) and five biochar to topsoil ratios
(0:1, 1:1, 1:2, 1:3, and 1:4 v/v). All soil and seedling leaf tissue laboratory results were computed using SAS software and treatment means separation
was compared using LSD at 5%. The results revealed significant variation in seedling nutrient uptake due to treatments and their interaction effects.
Nitrogen uptake of the seedlings treated by 13x19cm pot size and one to three ratios of biochar to topsoil was increased by 58.00% over the farmers
practice representing treatment. Phosphorus uptake of the seedling raised in 16x22cm pot size with 2g DAP/pot and one to three biochar to topsoil
ratio were increased by 46% and 43% over the local control, respectively. Potassium uptake of the seedling raised in 16x22cm pot size with one to
three biochar to topsoil ratio was increased by 180.00%, over the local control, respectively. Therefore, nutrient uptake of the seedling through the
use of biochar as a fertilizer at a lower rate provides alternative enhancement media options to coffee seedling growth.
Keywords: Biochar-ratio; Coffee seedling; Interaction effects; NPK; Pot size
... Biochar is an optimal solution to utilize the organic waste efficiently. Biochar gained by pyrolysis of organic residues can behave as a substitute and influence soil C sequestration and thus amends the physicochemical and biological properties of soil (García et al. 2016;Zhang et al. 2017). Biochar is the produce of thermal combustion of organic biomass in the absence of oxygen at a moderate temperature of 250-700 C (Lehmann and Joseph 2009). ...
The prominent concern of scientific community on sustainable agriculture merges the environmental objectives of soil management with increased food productivity to feed the ever-increasing world population. The concept of sustainable intensification has become apparent as a conspicuous outlying of this challenge. Soil is a momentous base of enriched nutrients and habitation for various
microfloras. Globally, the agricultural land has been depleted, and soil quality is degraded by disproportionate addition of chemical fertilizers and other contaminants. Excessive plant and animal agricultural residues are being burnt or wasted, which can be recycled to favorable means adding benefits to sustain soil productivity. Consequently, a reformed attention is a prerequisite to preserve agricultural soil for efficient crop production by utilizing agricultural residues;
biochar gives a natural solution for sustainable intensification of agricultural soil. Biochar as a soil organic amendment enriched with carbon enhances the eminence of soil and holds nutrients, thereby enhancing plant growth. In addition, it paves way for improved soil health as it affects the harmfulness, carriage, and destiny of heavy metals due to upgraded soil adsorption capacity. The improved soil properties and adsorption ability of biochar are attributed to their nutrient retention ability, high surface area, permeable nature, and ability to enhance microbial activity that leads to increased crop yield and productivity. The risk of soil compaction is minimized by biochar amendment as the stretchable asset of soil cores is decreased. Moreover, recycling agricultural residues into a precious soil nutrient makes a rural livelihood for the farming community. The productive impacts of biochar amendment on crop growth and soil quality recommends biochar as a sustainable solution to withstand deficit of essential nutrients in agricultural crop productivity. This review highlights the properties of biochar and its utility in sustainable agricultural production by ecological intensification of agroecosystem services.
... Biochar is an optimal solution to utilize the organic waste efficiently. Biochar gained by pyrolysis of organic residues can behave as a substitute and influence soil C sequestration and thus amends the physicochemical and biological properties of soil (García et al. 2016;Zhang et al. 2017). Biochar is the produce of thermal combustion of organic biomass in the absence of oxygen at a moderate temperature of 250-700 C (Lehmann and Joseph 2009). ...
... Biochar has been shown to have a direct fertilizing effect and increase soil nutrient stocks, most notably phosphorus (P) and potassium (K) (Biederman & Harpole, 2013;Gul & Whalen, 2016;Shepherd et al., 2017;Zhang et al., 2017). After pyrolysis, nutrients contained within the original feedstock biomass are concentrated in biochar and added directly to the soil upon application. ...
Produced through pyrolysis, biochars are used as a soil amendment. Differences in feedstock and processing result in differentiated products which impact their values in different soil conditions. Despite the enormous potential, biochars have not been widely used. This paper overviews the benefits and potential demand for biochar and features of supply chain, and identifies opportunities for viable introduction of biochars. The value of biochars should be evaluated as a part of the pyrolysis system that coproduces biochars and biofuels. Biochars can improve agricultural productivity and soil functioning and contribute to climate change mitigation through carbon sequestration. Furthermore, it can provide extra benefit by contributing to fire prevention. The cost of biochar system depends on the costs of feedstock acquisition, transportation, and processing. Biochar is most likely to be adopted in locations with marginal land and high‐value crop, and near low‐cost feedstock sources. The adoption of biochar can be enhanced by compensation for carbon sequestration, further investment in research, and learning of producers to enhance efficiency of the supply chain.
... Meanwhile, some forestry workers have applied biochar to forest soil to evaluate the biochar's effect on productivity of woodland. For example, applying wheat straw biochar into Chinese Torreya stand for half a year increased the soil nutrient contents and therefore enhanced the fresh weight of nuts by more than 15% on average [65]. Meanwhile, Wu et al. [66] applied biochar into a Pistacia chinensis plantation for one year and found that the plant height, ground diameter and crown width of Pistacia chinensis significantly (P < 0.05) increased by over 20% compared with the control. ...
... At the species level, the ability to maintain relatively consistent elemental nutrient composition and ratios (i.e., nutrient homeostasis) is fundamental to tree growth, but nutrient regimes could be altered by environmental changes (Mayor et al. 2014, Kou et al. 2017, Hogan et al. 2021. In managed agroforestry systems of subtropical regions, land managers generally obtain higher yields through massive N fertilization, often by exceeding the N requirement of trees (Zhang et al. , 2017. Therefore, it is important to identify tree response to excessive N stress associated with increasing N fertilization (Ye et al. 2018). ...
Nitrogen (N) enrichment from excessive fertilization in managed forests affects biogeochemical cycles on multiple scales, but our knowledge on how N availability shifts multi-nutrient stoichiometries (including macronutrients: N, P, K, Ca, Mg and micronutrients: Mn, Fe, Zn) within and among organs (root, stem and leaf) remains limited. To understand the difference among organs in terms of multi-nutrient stoichiometric homeostasis responding to N fertilization, a six-level N supply experiment was conducted through a hydroponic system to examine stem growth, multi-nutrient concentrations and stoichiometric ratios in roots, stems and leaves of two-year-old Chinese hickory (Carya cathayensis) saplings. Results showed that N supply significantly enhanced leaf length, width, basal diameter and sapling height. Increasing rates of N also significantly altered multi-nutrient concentrations in roots, stems and leaves. Macronutrients generally responded more positively than micronutrients within organs. Among organs, leaves and stems generally responded more actively to N supply than roots. The stoichiometric ratios of nutrients within different organs changed significantly with N supply but their direction and degree of change varied by organ. Specifically, increased N supply reduced the ratios of both macronutrients and micronutrients to N in plant organs while increased N supply elevated the ratios of P to other nutrients. With N fertilization, ratios of micronutrients decreased in leaves and stems and increased in roots. In particular, leaf N and stem Mn stoichiometries responded strongly to N availability, indicating stimulated N uptake but decreased risk of Mn2+ accumulation to excessive N. Overall, Chinese hickory saplings responded positively to increasing N availability in terms of stem growth, but the multi-nutrient stoichiometric homeostasis were distinctively organ-dependent. These results are expected to enhance our understanding of N-induced changes in nutrient homeostasis of multiple nutrients at the organ level and may offer new insights into how plants adapt to increasing N fertilization.
... It has been widely explored in soil management to improve the soil's physical, chemical, and biological properties (Kerré et al. 2017;Song et al. 2018;Ibrahim et al. 2021). Studies have shown that biochar could induce N retention to ensure its slow release for plant use (Pan et al. 2017;Zhang et al. 2017). However, it has also been reported to significantly accelerate nitrification, especially, in the short term (Hale et al. 2013;Song et al. 2013). ...
There are rising concerns about the negative environmental impacts of excessive N fertilizers used in agriculture. However, perennial crops require periodic large N doses for optimum growth. Hence, minimizing N application and regulating its long-term availability using N-cycling-mediating bacteria is a viable option that remains unexplored. We explored the comparative potentials of biochar and manure to provide a conducive condition for Bacillus subtilis and Bacillus licheniformis to improve their effects on N-cycling enzyme activity, the distribution of indigenous N-cycling-related bacteria, and long-term N availability for the growth of Nageia nagi after one year of single N dose. Results showed that NH 4 +-N did not vary across the treatments. While NO 3-N showed no variation between the fertilizer+biochar (FB) and fertilizer+manure (FM) treatments, dissolved organic-N (DON) increased in FB. Inoculation+fertilizer+biochar (FBI) induced a potential N-cycling enzyme activity, hence, an increase in NO 3-N, DON, and amino acid-N concentrations compared to inoculation+fertilizer+manure (FMI). This was associated with increased plant growth and leaf-N concentration in the inoculated treatments. Higher N-cycling due to Bacillus spp. inoculation increased the diversity of soil bacteria in FMI compared to FBI and other treatments. However, an increase in the relative abundance of some key nitrification-related bacterial taxa in FBI (Betaproteobac-teria, Gammaproteobacteria, and Actinobacteria) was associated with higher N-cycling enzyme activity, NO 3-N, DON, and amino acid-N concentrations compared to FMI. Due to low persistence, the long-term effect of Bacillus spp. on N release was mainly indirect, through their stimulatory effect on N-cycling enzyme activity and bacterial community. Therefore, periodic inoculation in biochar amended soils could be important in sustaining long-term N availability.
... Biochar contains abundant nutrients (e.g., NH 4 + , ortho-P; Gul and Whalen, 2016); its application in the experimental plots increased the soil AN and AP content (Supplementary Table A3), thus reducing the plants' dependence on internal circulation of N and P, leading to decreased N and P resorption in young bamboo. Zhang et al. (2017d) also observed that biochar amendment increased soil nutrient availability in Torreya grandis plantations. Moreover, biochar application promoted the formation of soil aggregates (Brodowski et al., 2006) and greatly enhanced soil fertility, which is attributed to biochar having a highly porous structure, large specific surface area, and a high CEC (Bird et al., 2008;Cheng et al., 2008). ...
Nutrient resorption can affect plant growth, litter decomposition, and nutrient cycling. Although the effects of nitrogen (N) and biochar fertilizers on soil nutrient concentrations and plant nutrient uptake have been studied, an understanding of how combined applications of N and biochar affect plant nutrient resorption in plantations is lacking. In this study, we applied N (0, 30, 60, and 90 kg N ha−1 yr−1 defined as N0, N30, N60, and N90, respectively) and biochar (0, 20, and 40 t biochar ha−1 defined as BC0, BC20, and BC40, respectively) to the soil of a Moso bamboo plantation. We investigated the effects of these treatments on N and phosphorus (P) resorption by young and mature bamboo plants, as well as the relationships between nutrient resorption and leaf and soil nutrient concentrations. Young bamboo showed significantly greater foliar N resorption efficiency (NRE) and P resorption efficiency (PRE) than mature bamboo. N addition alone significantly increased the N resorption proficiency (NRP) and P resorption proficiency (PRP) but significantly decreased the NRE and PRE of both young and mature bamboo. In both the N-free and N-addition treatments, biochar amendments significantly reduced the foliar NRE and PRE of young bamboo but had the opposite effect on mature bamboo. Foliar NRE and PRE were significantly negatively correlated with fresh leaf N and P concentrations and soil total P concentration but significantly positively correlated with soil pH. Our findings suggest that N addition inhibits plant nutrient resorption and alters the nutrient-use strategy of young and mature bamboo from “conservative consumption” to “resource spending.” Furthermore, biochar amendment enhanced the negative effect of N addition on nutrient resorption in young bamboo but reduced the negative effect on that of mature bamboo under N-addition treatments. This study provides new insights into the combined effects of N and biochar on the nutrient resorption of Moso bamboo and may assist in improving fertilization strategies in Moso bamboo plantations.
... According to Yao et al. [72], thermally converted organic materials can effectively absorb nitrate nitrogen, ammonium nitrogen in sandy soil. Zhang et al. [73] found that the application of pyrolyzed wheat straw at a low temperature strongly increases the availability of N, P and K in acidic soil with lower nutrient content. However, the properties of carbon materials, including pH, surface acid groups and ion exchange capacity, can have a great impact on the ability to absorb nutrients [54,56,74]. ...
Thermal biomass transformation products are considered to be one of the best materials for improving soil properties. The aim of the study was to assess the effect of charcoal after cavita-tion on the chemical and biochemical properties of soil. The study was carried out with a 10% aque-ous charcoal mixture that was introduced into loamy sand and clay at rates of 1.76%, 3.5%, 7.0%, and 14.0%. The effect of the application of cavitated charcoal was tested on Sorghum saccharatum (L.). Soil and plant material was collected to determine chemical and biochemical properties. The application of cavitated charcoal reduced the acidification of both soils. The highest rate (14.0%) of cavi-tated charcoal increased the content of soil total carbon (CTot) by 197% in the loamy sand compared to CTot in the control treatments, 19% for clay soil, respectively. The application of cavitated charcoal did not significantly change the total content of heavy metals. Regardless of the element and the soil used, the application of cavitated charcoal reduced the content of the CaCl2-extracted forms of heavy metals. Following the application of cavitated charcoal, the loamy sand soil presented an even lower content of the most mobile forms of the studied elements. It should also be noted that regardless of the soil texture, mobile forms of the elements decreased with the increased cavitated charcoal rate. The results of dehydrogenase and urease activity indicated the low metabolic activity of the microbial population in the soils, especially with the relatively high rates (7.0% and 14.0%) of cavitated charcoal. However, the cavitated charcoal used in the study showed a significant, positive effect on the amount of biomass S. saccharatum (L.), and its application significantly reduced the heavy metal content in the biomass of S. saccharatum (L.).
... Biochar is a carbon-rich organic material and a by-product produced from biomass by pyrolysis under high-temperature and low-oxygen conditions. It is obtained from the carbonization of organic wastes which can not only influence the sequestration of soil carbon but also modify its physicochemical and biological properties (Garcia et al. 2016;Zhang et al. 2017). In case of chemical properties, the addition of biochar significantly increased the pH (Jatav et al. 2017) and cation exchange capacity (CEC) of soil (Nigussie et al. 2012). ...
... Twigs of Torreya were collected from mature trees growing at an 18year-old plantation located 20 km from the university campus. The stand had been established with a local provenance and had been managed by means of routine practices (Zhang et al., 2017). In each sampling at the plantation, a single twig, approximately 20 cm long, with female flower buds, was randomly sampled and detached with scissors from the southward side of each tree, from the middle part of the crown. ...
A R T I C L E I N F O Keywords: Bud burst chilling requirement climatic variation endodormancy flowering leafout subtropical trees tree phenology A B S T R A C T Spring phenology is a key phenomenon mediating the effects of climate change on terrestrial plants and ecosystems , but in regard to subtropical trees, the dormancy mechanisms that regulate spring phenology are still poorly understood. It has been suggested recently that similarly to temperate and boreal trees, subtropical tree species also show endodormancy and a chilling requirement of endodormancy release. However, there are no previous experimental results on the chilling temperature range that is effective for endodormancy release in subtropical trees. We studied endodormancy and the chilling requirement in four subtropical tree species experimentally. In addition to chilling in natural conditions, we applied controlled chilling at several constant temperatures ranging from-2 to +15 • C. Our results show endodormancy and a chilling requirement in the tree species studied and reveal several differences among the four species in the manifestation and depth of endo-dormancy. Most importantly, our findings indicate that contrary to the prevailing mainline conception that chilling temperatures are generally restricted to those below +10 • C, higher temperatures of up to +15 • C are also effective for endodormancy release in the subtropical tree species examined. An exact upper threshold of +10.4 • C has been experimentally established for boreal Betula pubescens. We hypothesized that this difference would be explained by differences in the occurrence of low autumn temperatures between the two respective climates. We developed a method for testing the hypothesis by analysing long-term climatic records in relation to the experimental findings. Tentative results supported our hypothesis. On the basis of this novel result, we put forward the testable generalized hypothesis that in any climatic conditions where trees show endodormancy, the range of temperatures physiologically effective in endodormancy release represents the range of typical autumn air temperatures occurring in those particular climatic conditions.
... Biochar contains abundant nutrients (e.g., NH 4 + , Ortho-P) (Gul and Whalen 2016); its application in the experimental plots increased the soil AN and AP content (Table 1), thus reducing the plant's dependence on the internal circulation of N and P, leading to decreased N and P resorption in young bamboo. Zhang et al. (2017c) also observed that biochar amendment increased soil nutrient availability in Torreya grandis plantations. Moreover, biochar application promoted the formation of soil aggregates (Brodowski et al. 2006) and greatly enhanced soil fertility, which is attributed to biochar having a highly porous structure, large speci c surface area, and a high CEC of the soil (Bird et al. 2008;Cheng et al. 2008). ...
Background: While we know that N and biochar fertilizers affect soil nutrient concentrations and plant nutrient uptake, our understanding of how combined applications of N and biochar affect plant nutrient resorption in plantations is largely inadequate. A field experiment was conducted to investigate the effects of N (0, 30, 60, and 90 kg N ha⁻¹ yr⁻¹ or N0, N30, N60, and N90), in combination with biochar (0, 20, and 40 t biochar ha⁻¹ or BC0, BC20, and BC40) on N and P resorption by young and mature bamboo plants as well as the relationship between nutrient resorption and leaf nutrient and soil concentrations. Fresh and senescent leaf samples were collected in July 2016 and March 2017, respectively.
Results: Young bamboo showed significantly greater foliar N resorption efficiency (NRE) and P resorption efficiency (PRE) than mature bamboo. N additions alone significantly increased the N resorption proficiency (NRP) and P resorption proficiency (PRP) but decreased the NRE and PRE of both young and mature bamboo. In both the N-free (control) and N addition treatments, biochar amendments significantly reduced the foliar NRE and PRE of young bamboo but had the opposite effect on mature bamboo. Foliar NRE and PRE were significantly correlated with fresh leaf N and P concentrations and soil total P concentration.
Conclusion: Our findings suggest that N addition inhibits plant nutrient resorption and alters the nutrient-use strategy of young and mature bamboo from “conservative consumption” to “resource spending.” Furthermore, biochar amendment enhanced the negative priming effect of N addition on nutrient resorption of young bamboo but reduced the negative effect on that of mature bamboo. This study provides new insights into the combined effects of N and biochar additions on the nutrient resorption of Moso bamboo and may assist in improving fertilization strategies in Moso bamboo plantations.
... Furthermore, the fleshy seed cones of some Taxaceae species are popularly consumed by humans, such as Torreya grandis (cv. Merrilli) and Torreya nucifera, and in certain regions of China, To. grandis plantations are an economically important industry (Zhang et al., 2017;Chen and Jin, 2019). On the other hand, fruits from Taxus species are currently not popular for human consumption despite prehistoric evidence showing that Taxus fruits used to be consumed by humans (Uzquiano et al., 2014). ...
Ecosystem restoration is regarded as one of the most cost-effective ways of mitigating the effects of the ongoing climate- and anthropogenic changes and slow or revert the loss of biodiversity. Forest restoration has much potential to conserve forest specialist species and ecosystem services, by using multiple, native tree species to promote a high local diversity of trees, with likely positive effects on overall biodiversity and on ecosystem resilience. In this study, we assessed the potential of using two rare, native species of the yew family (Taxaceae) in forest restoration in China. Species of this family are only rarely used in reforestation despite their potential contribution to tree functional diversity as long-lived, shade-tolerant, evergreen understory trees with fleshy seed cones of value to frugivorous animals. By using species distribution modelling methods, we analysed national and local scale occurrence data for Taxus cuspidata and Torreya grandis to determine the climate-based potential ranges as well as important factors for growth on a local scale. The analyses showed that both species have large potential ranges driven mainly by precipitation and by comparing these ranges with the areas that have potential for sustaining forests, we found large areas available for forest restoration where these species could be included. On the local scale, we found that low light levels and low competition from co-occurring trees are more important for the growth of seedlings compared to the adult individuals of both species. If the ecological re- quirements for seedlings are ensured, i.e. by creating moderately shaded environments in which seedlings can escape competition, both Taxaceae species have high potential for reforestation in China and will increase the ecological qualities of a restored forest, and at the same time, the conservation of rare tree-species in their native ranges is ensured. Conclusively, both Ta. cuspidata and To. grandis are shade-tolerant, slow-growing trees that, by creating an evergreen scrubby layer, add to forest structural complexity and stability, thereby helping support ecosystem services and biodiversity, e.g. microhabitat and resources for birds and other animals.
Key message
Short-term nitrogen (N) deposition stimulates phosphorus (P) demand owing to the growth improvment of Phyllostachys edulis seedlings. Increased N loads led to the acquisition and utilization of sufficient P, while the limitation of P starvation could be alleviated by the higher activity of soil acid phosphatase and P use efficiency rather than P resorption from senescent organs.
Context
Plants in most terrestrial ecosystems are usually subjected to natural phosphorus (P) deficiency or surplus by overfertilization associated with increasing global nitrogen (N) deposition. As the widely distributed gramineous plant in Southern China, moso bamboo ( Phyllostachys edulis (Carrière) J. Houz) grows fast and it also shows a relatively good growth performance under the variable N and P conditions. However, few studies focus on the special mechanism of P mobilization and utilization of moso bamboo, especially with the N loads.
Aims
The objective of this study was to figure out the mechanisms of P mobilization and utilization in P. edulis seedlings under varying levels of soil P and N deposition conditions in the subtropical region of China.
Methods
We grew P. edulis seedlings under 3 experimental N deposition rates (0 (N −), 30 (N +), and 60 (N + +) kg N ha ⁻¹ ·a ⁻¹ ) and 3 levels of soil P (2.99 mg·kg ⁻¹ , soil available P content under natural conditions, denoted as P 1 ; 20 mg·kg ⁻¹ , P 2 ; and 40 mg·kg ⁻¹ , P 3 ). We measured growth traits and analyzed the related P use indices.
Results
Dry weight and P accumulation of new leaves and stems increased with increasing N loads under the 3 P treatments, with the positive effects of N deposition being stronger in the P 2 and P 3 treatments. Compared with N − , N + , and N + + significantly increased P use efficiency (PUE) (+ 15.54% and + 12.47%, respectively) regardless of soil P conditions. The P resorption efficiency showed a decreasing tendency under variable P conditions with increasing N, whereas PUE was further increased. Acid phosphatase (APase) activity and soil available P content were significantly improved by N loads in P 1 .
Conclusion
Phyllostachys edulis seedlings showed high growth plasticity and P mobilization mechanisms under different soil P availability with N loads. In general, N addition stimulated P demand of P. edulis seedlings owing to the growth promotion in the short period of experiment. A special P use mechanism in P deficiency conditions was that the limitation of P starvation was alleviated by the higher soil APase activity and PUE instead of P resorption from senescent organs. The long-term effect of N deposition on P mobilization and utilization in P. edulis forests requires further monitoring.
An industrial digestate was tested under pyrolysis to validate the influence of various temperatures on the potential of waste to provide biochars capable to improve soil productivity and enhance the efficiency of anaerobic digestion. The thermochemical conversion of digestate and the related kinetics were also examined by thermogravimetry and compared to those of biomass.
Digestate provided greater proportions of biochar (41.3–66.5 %wt.) than biomass (15.5–48.6 %wt.) at all temperatures, although cellulose and hemicellulose were less thermally stable than in the untreated biomass as indicated by the low activation energies of 150–180 kJ/mol and 83.1–88.2 kJ/mol, respectively compared to those of the polysaccharides in biomass. The behaviour of digestate during conversion and the quantity of generated biochar were both unaffected by the heating rate. Biochar yields however decreased from 55 to 41.3 %wt. in the isothermal tests with the increment of pyrolysis temperature from 300 to 700 °C. The soil amelioration ability of digestate was almost unaffected by pyrolysis at temperatures below 400 °C. Biochar produced at 500 °C possessed the greatest potential to improve soil fertility in the long-term due to its high alkalinity (pH 11.46) and modest cation exchange capacity (CEC) (72.2 cmol kg−1). The high-temperature biochar with slightly higher pH (11.51) and significantly larger surface area (116.1 m2/g) was the optimal choice for soil amelioration. Compared to the other biochars, the one produced at the highest temperature was also the best anaerobic digestion agent because of the higher alkalinity (pH 11.51), better minerals content (P, K, Ca, Al) and larger than 100 m2/g surface area, all properties that are desirable for the improvement of stability, methane productivity and mitigation of CO2, H2S and free-NH3 in a digestion system.
AimsNitrogen (N) enrichment from excessive fertilization influences the coupling of nutrients in terrestrial ecosystems, but whether it could alter the scaling relationships between multinutrients [including macronutrients: N, phosphorus (P), potassium, calcium (Ca), magnesium (Mg) and micronutrients: manganese (Mn), iron (Fe) and zinc] remains unclear.Methods
We conducted an control experiment using two-year-old Chinese hickory (Carya cathayensis) saplings in hydroponics system, with six levels of N fertilization, to evaluate variations in scaling relationships of multinutrient concentrations in vegetative organs of Chinese hickory under consistent N fertilization.ResultsCorrelational relationships between multinutrients concentrations were most significant in leaves, while stems and roots were less related. Micronutrients, in particular, were mostly negatively related to macronutrients. Significant allometric relationships were detected among multinutrients, but the response patterns were both organ- and nutrient-dependent. For example, positive allometric relationships were detected in N versus other macronutrients while negative allometric relationships were observed with N related to micronutrient response. Leaves generally presented more positive allometric relationships than negative relationships. Beyond expectation, increasing N fertilization minimally altered the scaling exponents between multinutrients, except stem N-Mg, root Mn-Fe, root P-Ca, and leaf P-Ca.Conclusions
Chinese hickory saplings displayed relatively high nutrient homeostasis when excessive N fertilizer was applied. These results will enhance our understanding of organ-dependent allometric relationships between multinutrients in forest trees and may offer new insights into how plants develop adaptive functional traits to increasing N fertilization.
Arbuscular mycorrhizal fungi (AMF) are taken as bioameliorators to alleviate the detrimental effects of salt stress. However, how AMF affect the performance of Cinnamomum camphora, an economically important species, remains unclear. In this study, we evaluated the interactive effects of AMF and salinity on the growth, nutrient acquisition, and ion ratios of C. camphora. A factorial experiment was implemented in a greenhouse with four fungal regimes (inoculation with sterilized AMF or with Funneliformis mosseae or Rhizophagus irregularis either alone or in combina-tion), and three salt regimes (0, 50, and 200 mM NaCl). Results showed that salinity alone significantly reduced the total dry weight, mycorrhizal colonization, K+ concentration, and ionic homeostasis (particularly K+:Na+, Mg2+:Na+, and Ca2+:Na+) of whole plants. Mycorrhizal inoculation, particularly with R. irregularis, strongly mitigated some of the detrimental effects of salinity, enhancing the salt tolerance of C. camphora. Furthermore, the host plants benefited from the presence of AMF, mainly because they enhanced P and Mn2+ concentrations in the shoots, adjusted biomass allocation, and shifted the selective transporting capacity of K+ over Na+ from roots to shoots. Our results suggested that building mycorrhizal association between C. camphora and R. irregularis may be useful for plant cultivation in coastal areas.
The use of biochar is expected to improve soil fertility and close nutrient cycles in degraded strongly weathered tropical soils. We, therefore, hypothesized that biochar amendment to tree plantations (a) increases nutrient fluxes with litterfall alone and with mineral fertilizer plus lime and (b) reduces N losses reflected by lower δ15N values of litterfall and soils than in unamended controls. We grew the native leguminous Schizolobium parahyba var. amazonicum (Ducke) Barneby and the exotic Gmelina arborea Roxb at two sites. We used a replicated full factorial split‐split‐plot design of amendment of mineral fertilizer plus lime, 3 and 6 t ha–1 biochar, and a control. We collected litterfall biweekly (2012‐2013) and topsoil samples (0‐0.25 m) in 2009 before tree planting, in 2011 and 2013. Fertilizer plus lime increased the mean annual concentrations of P, Ca and Zn in litterfall but decreased that of Mn. At the same time, fertilizer plus lime increased the annual fluxes of nutrients, Na and Al with litterfall. During the dry season, biochar decreased the N concentration in litterfall and the K flux with litterfall. During the rainy season, biochar increased the concentrations of Ca and Zn in litterfall and their fluxes with litterfall. Biochar did not influence the δ15N values of soil and litterfall after 51 months of tree growth. Fertilizer plus lime decreased the δ15N values of soil, because of the lower δ15N value of the used urea (‐0.30‰) than the soil (4.5‐7.8%). Moreover, fertilizer plus lime increased the δ15N values of litterfall, possibly because of enhanced 14N leaching from the N‐rich canopies. The amendment of up to 6 t ha‐1 biochar did not contribute to close nutrient cycles.
Rising global temperature, pollution load, and energy crises are serious problems, recently facing the world. Scientists around the world are ambitious to find eco-friendly and cost-effective routes for resolving these problems. Biochar has emerged as an agent for environmental remediation and has proven to be the effective sorbent to inorganic and organic pollutants in water and soil. Endowed with unique attributes such as porous structure, larger specific surface area (SSA), abundant surface functional groups, better cation exchange capacity (CEC), strong adsorption capacity, high environmental stability, embedded minerals, and micronutrients, biochar is presented as a promising material for environmental management, reduction in greenhouse gases (GHGs) emissions, soil management, and soil fertility enhancement. Therefore, the current review covers the influence of key factors (pyrolysis temperature, retention time, gas flow rate, and reactor design) on the production yield and property of biochar. Furthermore, this review emphasizes the diverse application of biochar such as waste management, construction material, adsorptive removal of petroleum and oil from aqueous media, immobilization of contaminants, carbon sequestration, and their role in climate change mitigation, soil conditioner, along with opportunities and challenges. Finally, this review discusses the evaluation of biochar standardization by different international agencies and their economic perspective.
Improving productivity of saline soils under drought condition is critical for sustainable agricultural development in arid areas. Whether biochar addition can interact with drought and salinity on fruit yield and quality remains unclear. A pot study was conducted to examine the effects of water, salinity and biochar addition on tomato yield and quality in a solar greenhouse of northwest China. There were twelve treatments combining two irrigation levels of high (W1) and low irrigation (W2 = 2/3 W1), three salinity levels with 0%, 0.3% and 0.6% of soil dry weight salts, referred to S0, S1, and S2, respectively, and two biochar addition levels with 0 (B0) and 1% (B1) of soil dry weight. Biochar, water, salinity, and the interaction between water and salinity were found significant affecting yield and irrigation water productivity (IWP). Biochar addition reduced yield and IWP, ranging from by 7% of W2S0 to 43% of W1S2. The difference in yield and IWP between W1 and W2 was greater for lower salinity treatments. The reduction percentage of W2, relative to W1, was 70%, 38%, and 29% for yield, 58%, 14%, and 0.9% for IWP under S0, S1, and S2, respectively. The effects of water, salinity and biochar treatments was found inconsistent for different quality parameters. Adding biochar had no significant effect on firmness, and slightly increased total soluble solids (TSS) and Vitamin C (VC) at both irrigation levels, while lower irrigation and higher salinity generally led to higher TSS and VC. The absolute slope value of the linear regression of yield and quality parameters with soil electrical conductivity was smaller under W2, relative to W1, indicating that the salinity effect was less pronounced when water stress was greater. The results are valuable in developing and evaluating remedy measures for improving saline soil productivity in arid areas.
Soil is an integral part of the ecosystem because it serves as a habitat for various microorganisms and lays the foundation for
supporting plant growth and development. Therefore, factors such as increased anthropogenic activities hand by hand with
other natural processes that harm the ecosystem may eventually lead to a decline in soil quality and fertility, hindering the
growth of plants and soil microbial communities. Given the current global scenario of increasing human intervention, it is
essential to find effective measures and reliable technologies to restore soil quality. Biochar is an emerging soil ameliorant
employed for soil health restoration and is primarily generated through the anoxygenic pyrolysis of biomass. The biochar
application in soil remediation may be beneficial due to biochar’s unique physicochemical properties, including high carbon and metal fixation abilities. In addition, biochar possesses abilities to reduce the plant's environmental stress injuries.
This review briefly overviewed the ingredients and mechanism of biochar productions. We then emphatically reviewed the
advances in biochar applications in soil bioremediation, soil microflora growth stimulation, and the alleviation of various
biotic and abiotic stresses in plants
Higher presence of organic and inorganic components in water bodies is consequent to extreme environmental pollution. The persistent nature and toxicity of wastewater contaminant pose hazards to the environment and human lives and, hence, its sequestration before discharge into water streams is obligatory. Wastewater treatment plants and other conventional treatments (physicochemical) are found inefficient due to low removal rate, requirement of high cost, and high energy extensive technologies. Thermochemical conversion of biomass into biochar is identified as a sustainable alternative for pollutant risk mitigation for a better environment and agro-waste management. The adsorption potential of biochar surface and the properties of biochar are highly influenced by the feedstock used and the procedure conditions in various thermochemical processes that produce it. However, to enhance the removal efficiency, a pristine biochar is treated with various modifications strategies (acid and alkali treatment, steam and gas treatment, impregnation, and microwave assisted activation). This work is focused on summarizing the various feedstock materials employed for biochar synthesis along with their properties. Moreover, sorption of environmental pollutants and the mechanism governing contaminant removal via pristine as well as modified/engineered biochar are comprehensively discussed. Other environmental applications including carbon sequestration, reducing greenhouse gas emission, soil amendment, and reducing bioavailability of contaminants are reported. Finally, research prospects including cost reduction, evaluation of toxic impacts, reusability, and large-scale production for biochar application have been touched upon as suggestions for further thought.
Declining soil fertility and inefficient water and nutrient use pose a growing challenge to increasing agricultural production to meet growing global food demand. As a soil amendment, biochar can potentially serve in addressing these issues; however, its impacts on nutrient leaching from soils of different pre-existing fertility levels are poorly understood. A potted green pepper (Capsicum annuum L. var. Red Night) production system, arranged in a randomized complete block design, imposed two soil fertility management approaches (‘fertile’: standard soil + [N:P:K (kg ha ⁻¹) 140:165:160] vs. ‘less fertile soil’: 1:1 standard soil : sand, [N:P:K (kg ha ⁻¹) 140:190:240], factorially combined with three levels of wheat straw biochar amendment [0%, 1%, and 3% (w/w)]. Biochar treatment effects on nutrient leaching (NO3−-N and PO43−-P) and plant yield were assessed for each soil fertility management approach. Across soil fertility types, biochar amendments (vs. the lack thereof) significantly decreased (p≤0.05) leachate volume (68%–91%) and cumulative NO3−-N (78%–93%) and PO43−-P (80%–99%) losses, whereas NO3−-N, and PO43−-P concentrations in the leachate were only significantly reduced (p≤ 0.05) under the 3% biochar amendment. Pepper marketable yield in the less fertile soil was significantly (40%, p≤0.05) greater under the 3% biochar amendment than the non-amended treatment; however, no such difference existed in the fertile soil given its initially high soil nutrient levels. While farmers can amend soils with biochar to reduce nutrient leaching, its impact on plant productivity will depend on the rate of amendment.
PurposeBiochar and organic amendments can improve soil quality, but their combined effects on plant growth as well as soil microbial functions deserve further investigation.Materials and methodsWe established an 8-month field experiment to explore the effects of biochar (0, 10 t ha−1), organic amendments (10 t ha−1 sheep manure and 2 t ha−1 rapeseed cake), and their combinations on plant growth and soil quality in a Torreya grandis plantation.Results and discussionOrganic amendments significantly (P < 0.05) increased soil available and total P contents as well as mineral nutrients in leaves. Biochar significantly increased soil available P and K and total K contents. Biochar combined with sheep manure rather than rapeseed cake displayed a significant (P < 0.05) increase in plant quality and soil nutrients in comparison with manure or rapeseed cake addition alone. Biochar combined with sheep manure significantly increased microbial activity (indicated by microbial substrate utilization rate) compared with manure alone treatment. In addition, organic amendments in combination with biochar generally had no significant effects on microbial diversity indices, but they had some interactive effects on some bacterial taxa, such as Proteobacteria and Actinobacteria, and predicted metabolism functions. Changes in soil nutrient contents were closely linked with soil bacterial community composition and improvements in plant quality.Conclusions
The results showed that 10 t ha−1 biochar co-applied with 10 t ha−1 sheep manure was suitable for the promotion of soil fertility and plant growth in a Torreya grandis plantation.
Worldwide, many soils are impacted by degradation processes, which impose a risk to sustainable food production. There is a pressing need to limit these negative impact constraints to sustain the proper functioning of the soil-biota system and soil productivity. Biochar can be a nature-friendly solution for soil remediation; however, knowledge is incomplete in many aspects in this field, like the potential of biochar and biochar-based products as agents to immobilize toxic substances, including heavy metals (HMs) found in the soil. In this study, we investigated the effect of two biochar substrates (BSs) (1. biochar blended with farmyard manure as BS1, and 2. biochar blended with farmyard manure and digestate as BS2) at rates of 10 and 20 t ha⁻¹ applied without or with fertilization (BS + F) on the immobilization of HMs in texturally different soils (1. sandy Arenosol, 2. loamy Chernozem, Slovakia). The results showed that application of BS had different effects in relation to soil textures. In sandy soil, BS improved soil properties, such as cation exchange capacity (an increase from 20 to 93%), soil organic carbon content (SOC) (an increase from 3 to 26%) and humic substances (HSs) stability (an increase from 12 to 20%). In loamy soil, SOC increased due to BS and BS + F in the range 3–19% and 12–55%, respectively. In both soils, the total content of HMs did not exceed the threshold limits for individual soils after BS and BS + F application. In sandy soil, the immobilization of HMs was due to a higher SOC content and a fulvic acids (FAs) content, while in loamy soil their elimination depended on a higher available phosphorus content.
Drought is the greatest threat to world food security, seen as the catalyst for the great famines of the past. Given that the world’s water supply is limited, it is likely that future demand of food for increasing population will further exacerbate the drought effects. Therefore, the present study was aimed to investigate the effect of biochar and plant growth promoting rhizobacteria (PGPR) Sphingobacterium pakistanensis (NCCP246) and Cellulomonas pakistanensis (NCCP11) on agronomic and physiological attributes of Vicia faba two varieties Desi (V1) and Pulista (V2) under induced drought stress. The seeds were sown in earthen pots filled with 3 kg sand and soil (1:2), and biochar (0 and 5% w/w) in triplicate arranged in complete randomized design. Analysis of biochar possessed 0.49 g cm−3 bulk density, 9.6 pH; 5.4 cmol kg−1 cation exchange capacity, 3.64% organic carbon and EC 6.7 ds/m. Agronomic attributes including seed LAI, LAR, SVI, %PHSI and RWC were improved by 30.4–180.4%, 14.37–47.20%, 37.64–50.91%, 18.21–30.80, and 35.82–54.34% in both varieties by the co-application of biochar and PGPR. Stomatal physiology and epidermal vigor was successfully improved by the application of PGPR and biochar as analyzed by scanning electron microscopy (SEM). Photosynthetic pigments, flavonoids, phenols, proline and glycine betaine were amplified by 58.33–173.8%, 50.59–130.33%, 46.58–86.62%, 46.66–109.30%, 35.74–56.10%, and 21.96–77.22% in both varieties by the co-application of biochar and PGPR. So, the present work concluded that, combined application of biochar and PGPR could be an effective strategy to alleviate the adversities of drought in V. faba growing in drastic ecosystems.
The prominent concern of scientific community on sustainable agriculture merges the environmental objectives of soil management with increased food productivity to feed the ever-increasing world population. The concept of sustainable intensification has become apparent as a conspicuous outlying of this challenge. Soil is a momentous base of enriched nutrients and habitation for various microfloras. Globally, the agricultural land has been depleted, and soil quality is degraded by disproportionate addition of chemical fertilizers and other contaminants. Excessive plant and animal agricultural residues are being burnt or wasted, which can be recycled to favorable means adding benefits to sustain soil productivity. Consequently, a reformed attention is a prerequisite to preserve agricultural soil for efficient crop production by utilizing agricultural residues; biochar gives a natural solution for sustainable intensification of agricultural soil. Biochar as a soil organic amendment enriched with carbon enhances the eminence of soil and holds nutrients, thereby enhancing plant growth. In addition, it paves way for improved soil health as it affects the harmfulness, carriage, and destiny of heavy metals due to upgraded soil adsorption capacity. The improved soil properties and adsorption ability of biochar are attributed to their nutrient retention ability, high surface area, permeable nature, and ability to enhance microbial activity that leads to increased crop yield and productivity. The risk of soil compaction is minimized by biochar amendment as the stretchable asset of soil cores is decreased. Moreover, recycling agricultural residues into a precious soil nutrient makes a rural livelihood for the farming community. The productive impacts of biochar amendment on crop growth and soil quality recommends biochar as a sustainable solution to withstand deficit of essential nutrients in agricultural crop productivity. This review highlights the properties of biochar and its utility in sustainable agricultural production by ecological intensification of agroecosystem services.KeywordsAgricultural residuesBiocharEco-intensificationSoil management
The adoption of green production behaviors (GPBs) in non-timber forest product (NTFP) operations can improve soil quality and mitigate run-off and soil erosion in mountainous areas, which can support sustainable industry development. Selling NTFPs by e-commerce rather than traditional face-to-face trading can expand markets, prevent any high-quality product premium being lost to profit-seeking middlemen, and reduce the information asymmetry about the quality of products. Therefore, improvements in product quality can achieve a price premium, which can stimulate rural households engaged in NTFP operations (i.e. NTFP households) to adopt GPBs. This study uses survey data from 429 NTFP households in Zhejiang Province in southeastern China and econometric modelling to test whether e-commerce can foster NTFP households' adoption of GPBs The results show that the NTFP households are not commonly adopting GPBs but e-commerce does encourage their adoption of GPBs. In particular, e-commerce has a positive effect on the NTFP households' use of organic fertilizer and formula fertilizer (informed by soil testing). E-commerce has a negative effect on the households’ use of high-toxicity pesticides and the frequency of using pesticides. Compared with small-scale NTFP households whose forestland size is lower than the mean of the total sample (i.e. <1.91 ha), e-commerce has a stronger effect on the adoption of GPBs by large-scale (i.e. >1.91 ha) NTFP households. The implication for policymakers from these findings is that e-commerce can be used to drive NTFP households to adopt GPBs in countries with free markets and functioning e-commerce platforms.
The replant disease refers to abnormal crop growth caused by continuous cultivation of the same or related species on the same soil, and often occurring in crops and orchards. Recently, replant disease have become a major factor constraining the sustainable development of global agriculture and fruit trees. The causes of replant disease include biological and abiotic factors, but in the final analysis, they are caused by changes in the soil environment. Soil environment is closely related to soil productivity. A decline of soil quality results in poor crop growth and reduced yield. The causes of soil environment changes mainly include intensive soil tillage, rapid industrialization, soil pollution, destruction of soil micro-ecosystem and substances secreted by plants under replant condition. Biochar, a porous carbon material prepared from pyrolysis of biomass (agricultural waste, etc.), is widely used as an amendment and adsorbent. To understand the role of biochar in alleviating replant disease, we summarized the previous research results of biochar application in replant soil. The following points are summarized: (1) soil problems and their effects on plants; (2) effects of biochar on replant soil environment; and (3) effects of biochar on alleviating replant disease. Overall, the literature suggests that biochar is an effective measure to amendment soil environment and alleviates replant disease. Further studies on biochar will enhance our understanding of biochar–soil interactions, and its long-term impact of biochar on soil environment.
The individual role of biochar, compost and PGPR has been widely studied in increasing the productivity of plants by inducing resistance against phyto-pathogens. However, the knowledge on combined effect of biochar and PGPR on plant health and management of foliar pathogens is still at juvenile stage. The effect of green waste biochar (GWB) and wood biochar (WB), together with compost (Comp) and plant growth promoting rhizobacteria (PGPR; Bacillus subtilis ) was examined on tomato ( Solanum lycopersicum L.) physiology and Alternaria solani development both in vivo and in vitro. Tomato plants were raised in potting mixture modified with only compost (Comp) at application rate of 20% (v/v), and along with WB and GWB at application rate of 3 and 6% (v/v), each separately, in combination with or without B. subtilis . In comparison with WB amended soil substrate, percentage disease index was significantly reduced in GWB amended treatments (Comp + 6%GWB and Comp + 3%GWB; 48.21 and 35.6%, respectively). Whereas, in the presence of B. subtilis disease suppression was also maximum (up to 80%) in the substrate containing GWB. Tomato plant growth and physiological parameters were significantly higher in treatment containing GWB (6%) alone as well as in combination with PGPR. Alternaria solani mycelial growth inhibition was less than 50% in comp, WB and GWB amended growth media, whereas B. subtilis induced maximum inhibition (55.75%). Conclusively, the variable impact of WB, GWB and subsequently their concentrations in the soil substrate was evident on early blight development and plant physiology. To our knowledge, this is the first report implying biochar in synergism with PGPR to hinder the early blight development in tomatoes.
Millions of tons of dyes, agrochemicals, and pharmaceuticals are produced globally per year and a substantial part is released in the environment. Several chemicals persist and accumulate in the environment and exhibit detrimental effects on organisms. They also lead to the development of carcinogenicity, endocrine disruption, antimicrobial resistance in pathogenic microorganisms, causing a great threat to health of humans. Chemicals present in the environment are removed by various biological and chemical processes. Among them, adsorption is better suited owing to its effectiveness, low cost, ease of operation. A number of adsorbates such as natural clay, charcoal, carbon nanotubes, and biochar have been utilized. Biochar is a carbonaceous material formed from plant biomass, when it is heated in limited supply of oxygen. It has porous structure, charged surface, and functional groups, which help in adsorption of vast array of pollutants. In this chapter, we have reviewed recent trends in biochar-based removal of dyes, agrochemicals, and pharmaceuticals. We have also discussed the mechanisms behind the adsorption and future prospects of this approach in abatement of these pollutants.
Aims
The combined effects of nitrogen (N) deposition and management practices on fine root decomposition remain unknown. The objective of this study was to investigate the effects of the two factors on fine root decay in Moso bamboo plantations.
Methods
This study was performed over a three-year period and included three nitrogen treatments (30, 60, and 90 kg N ha⁻¹ yr.⁻¹) and two management practices (conventional and intensive).
Results
Fine root decomposition was significantly affected by N inputs and management practices both separately and in combination (P < 0.01). N inputs had a stronger effect than management practices. The low-N input (30 kg N ha⁻¹ yr.⁻¹) accelerated fine root decomposition and nutrient release, whereas high-N inputs (≥ 60 kg N ha⁻¹ yr.⁻¹) inhibited decomposition and nutrient release. Moreover, intensive management practices strengthened the inhibitory effects of the high-N inputs.
Conclusions
Moderate N deposition (< 60 kg N ha⁻¹ yr.⁻¹) may decrease soil carbon storage but increase Moso bamboo productivity, while excessive N deposition (≥ 90 kg N ha⁻¹ yr.⁻¹) may have opposing effects. The combined effects of management practices and nitrogen amendment should be considered when estimating the effects of increasing atmospheric N deposition on plantation ecosystems.
Relations among nitrogen load, soil acidification and forest growth have been evaluated based on short-term (< 15 years) experiments, or on surveys across gradients of N deposition that may also include variations in edaphic conditions and other pollutants, which confound the interpretation of effects of N per se. We report effects on trees and soils in a uniquely long-term (30 years) experiment with annual N loading on an un-polluted boreal forest. Ammonium nitrate was added to replicated (N=3) 0.09 ha plots at two doses, N1 and N2, 34 and 68 kg N ha(-1) yr(-1), respectively. A third treatment, N3, 108 kg N ha(-1) yr(-1), was terminated after 20 years, allowing assessment of recovery during 10 years. Tree growth initially responded positively to all N treatments, but the longer term response was highly rate dependent with no gain in N3, a gain of 50 m(3) ha(-1) stemwood in N2 and a gain of 100 m(3) ha(-1) stemwood in excess of the control (N0) in N1. High N treatments caused losses of up to 70% of exchangeable base cations (Ca2+, Mg2+, K+) in the mineral soil, along with decreases in pH and increases in exchangeable Al3+. In contrast, the organic mor-layer (forest floor) in the N-treated plots had similar amounts per hectare of exchangeable base cations as in the N0 treatment. Magnesium was even higher in the mor of N-treated plots, providing evidence of up-lift by the trees from the mineral soil. Tree growth did not correlate with the soil Ca/Al ratio (a suggested predictor of effects of soil acidity on tree growth). A boron deficiency occurred on N-treated plots, but was corrected at an early stage. Extractable NH4+ and NO(3)(-)were high in mor and mineral soils of on-going N treatments, while NH4+ was elevated in the mor only in N3 plots. Ten years after termination of N addition in the N3 treatment, the pH had increased significantly in the mineral soil; there were also tendencies of higher soil base status and concentrations of base cations in the foliage. Our data suggest the recovery of soil chemical properties, notably pH, may be quicker after removal of the N-load than predicted. Our long-term experiment demonstrated the fundamental importance of the rate of N application relative to the total amount of N applied, in particular with regard to tree growth and C sequestration. Hence, experiments adding high doses of N over short periods do not mimic the long-term effects of N deposition at lower rates.
Trace elements (TEs) contamination is one of the main abiotic stresses which limit plant growth and deteriorate the food quality by their entry into food chain. In recent, biochar (BC) soil amendment has been widely reported for the reduction of TE(s) uptake and toxicity in plants. This review summarizes the role of BC in enhancing TE(s) tolerance in plants. Under TE(s) stress, BC application increased plant growth, biomass, photosynthetic pigments, grain yield and quality. The key mechanisms evoked are immobilization of TE(s) in the soil, increase in soil pH, alteration of TE(s) redox state in the soil, and improvement in soil physical and biological properties under TE(s) stress. However, these mechanisms vary with plant species, genotypes, growth conditions, duration of stress imposed, BC type and preparation methods. This review highlights the potential for improving plant resistance to TE(s) stress by BC application and provides a theoretical basis for application of BC in TE(s) contaminated soils worldwide.
The potential of biochar to improve crop productivity has received interest in recent years; however, little is known about the effects of biochar on crop nutritional quality. In this study, effects of three different biochars (wheat straw biochar, poplar biochar and olive residues biochar) were determined on the major fruit-size parameters, physico-chemical and nutritional properties of tomato (Lycopersicon esculentum L.) cv. Rio Grande. Application of biochar alone was sufficient to sustain the fruit growth, but results were affected by feedstock source of biochar. There were no significant differences in size and weight parameters and the sugar content was not significantly modified by biochar amendment. On the other hand, secondary metabolites showed changes relating to biochar type. Total phenol and flavonoid contents, as well as antioxidant activity, were higher in fruits grown in substrate amended with straw biochar and olive residues biochar. Lycopene, β carotene and lutein concentrations from tomato fruits grown on substrates amended with different biochars were significantly lower than from the control. The data require confirmation in field experiments; however, this study offers new knowledge about the biochar effects on horticultural crops.
Soil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to
enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar
mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting
considerably promoted biochars’ positive effects, largely by nitrate (nutrient) capture and delivery.
In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a
sandy-poor soil amended with 2% (w/w) co-composted biochar (BCcomp). Conversely, addition of 2%
(w/w) untreated biochar (BCpure) decreased the biomass to 60% of the control. Growth-promoting
(BCcomp) as well as growth-reducing (BCpure) effects were more pronounced at lower nutrient-supply
levels. Electro-ultra filtration and sequential biochar-particle washing revealed that co-composted
biochar was nutrient-enriched, particularly with the anions nitrate and phosphate. The captured
nitrate in BCcomp was (1) only partly detectable with standard methods, (2) largely protected against
leaching, (3) partly plant-available, and (4) did not stimulate N2O emissions. We hypothesize that
surface ageing plus non-conventional ion-water bonding in micro- and nano-pores promoted nitrate
capture in biochar particles. Amending (N-rich) bio-waste with biochar may enhance its agronomic
value and reduce nutrient losses from bio-wastes and agricultural soils.
Increased reactive nitrogen (Nr) deposition has raised the amount of N available to organisms and has greatly altered the transfer of energy through food webs, with major consequences for trophic dynamics. The aim of this review is to: 1) clarify the direct and indirect effects of Nr deposition on forest and lake food webs in N limited biomes, 2) compare and contrast how aquatic and terrestrial systems respond to increased Nr deposition, and 3) identify how the nutrient pathways within and between ecosystems change in response to Nr deposition. We present that Nr deposition releases primary producers from N limitation in both forest and lake ecosystems and raises plants’ N-content which in turn benefits herbivores with high N requirements. Such trophic effects are coupled with a general decrease in biodiversity caused by different N-use efficiencies; Slow-growing species with low rates of N turnover are replaced by fast-growing species with high rates of N turnover. In contrast, Nr deposition diminishes belowground production in forests, due to a range of mechanisms that reduce microbial biomass, and decreases lake benthic productivity by switching herbivore growth from N to phosphorus (P) limitation, and by intensifying P limitation of benthic fish. The flow of nutrients between ecosystems is expected to change with increasing Nr deposition. Due to higher litter production and more intense precipitation, more terrestrial matter will enter lakes. This will benefit bacteria and will in turn boost the microbial food web. Additionally, Nr deposition promotes emergent insects which subsidize the terrestrial food web as prey for insectivores or by dying and decomposing on land. So far most studies have examined Nr deposition effects on the food web base, whereas our review highlights that changes at the base of food webs substantially impact higher trophic levels and therefore food web structure and functioning.This article is protected by copyright. All rights reserved.
The stability and decomposition of biochar are fundamental to understand its persistence in soil, its contribution to carbon (C) sequestration, and thus its role in the global C cycle. Our current knowledge about the degradability of biochar, however, is limited. Using 128 observations of biochar-derived CO2 from 24 studies with stable (13C) and radioactive (14C) carbon isotopes, we meta-analyzed the biochar decomposition in soil and estimated its mean residence time (MRT). The decomposed amount of biochar increased logarithmically with experimental duration, and the decomposition rate decreased with time. The biochar decomposition rate varied significantly with experimental duration, feedstock, pyrolysis temperature, and soil clay content. The MRTs of labile and recalcitrant biochar C pools were estimated to be about 108 days and 556 years with pool sizes of 3% and 97%, respectively. These results show that only a small part of biochar is bioavailable and that the remaining 97% contribute directly to long-term C sequestration in soil. The second database (116 observations from 21 studies)
was used to evaluate the priming effects after biochar addition. Biochar slightly retarded the mineralization of soil organic matter (SOM; overall mean: 3.8%, 95% CI=8.1–0.8%) compared to the soil without biochar addition. Significant negative priming was common for studies with a duration shorter than half a year (8.6%), crop-derived biochar (20.3%), fast pyrolysis (18.9%), the lowest pyrolysis temperature (18.5%), and small application amounts (11.9%). In contrast, biochar addition to sandy soils strongly stimulated SOM mineralization by 20.8%. This indicates that biochar stimulates microbial activities especially in soils with low fertility. Furthermore, abiotic and biotic processes, as well as the characteristics of biochar and soils, affecting biochar decomposition are discussed. We conclude that biochar can persist in soils on a centennial scale and that it has a positive effect on SOM dynamics and thus on C sequestration.
Biochar may contribute to climate change mitigation at negative cost by sequestering photosynthetically fixed carbon in soil while increasing crop yields. The magnitude of biochar’s potential in this regard will depend on crop yield benefits, which have not been well-characterized across different soils and biochars. Using data from 84 studies, we employ meta-analytical, missing data, and semiparametric statistical methods to explain heterogeneity in crop yield responses across different soils, biochars, and agricultural management factors, and then estimate potential changes in yield across different soil environments globally. We find that soil cation exchange capacity and organic carbon were strong predictors of yield response, with low cation exchange and low carbon associated with positive response. We also find that yield response increases over time since initial application, compared to non-biochar controls. High reported soil clay content and low soil pH were weaker predictors of higher yield response. No biochar parameters in our dataset—biochar pH, percentage carbon content, or temperature of pyrolysis—were significant predictors of yield impacts. Projecting our fitted model onto a global soil database, we find the largest potential increases in areas with highly weathered soils, such as those characterizing much of the humid tropics. Richer soils characterizing much of the world’s important agricultural areas appear to be less likely to benefit from biochar.
Background and aims
For the last decade, there has been an increasing global interest in using biochar to mitigate climate change by storing carbon in soil. However, there is a lack of detailed knowledge on the impact of biochar on the crop productivity in different agricultural systems. The objective of this study was to quantify the effect of biochar soil amendment (BSA) on crop productivity and to analyze the dependence of responses on experimental conditions.
Methods
A weighted meta-analysis was conducted based on data from 103 studies published up to April, 2013. The effect of BSA on crop productivity was quantified by characterizing experimental conditions.
Results
In the published experiments, with biochar amendment rates generally <30 t ha−1, BSA increased crop productivity by 11.0 % on average, while the responses varied with experimental conditions. Greater responses were found in pot experiments than in field, in acid than in neutral soils, in sandy textured than in loam and silt soils. Crop response in field experiments was greater for dry land crops (10.6 % on average) than for paddy rice (5.6 % on average). This result, associated with the higher response in acid and sandy textured soils, suggests both a liming and an aggregating/moistening effect of BSA.
Conclusions
The analysis suggests a promising role for BSA in improving crop productivity especially for dry land crops, and in acid, poor-structured soils though there was wide variation with soil, crop and biochar properties. Long-term field studies are needed to elucidate the persistence of BSA’s effect and the mechanisms for improving crop production in a wide range of agricultural conditions. At current prices and C-trading schemes, however, BSA would not be cost-effective unless persistent soil improvement and crop response can be demonstrated.
A pot trial was carried out to investigate the effect of biochar produced from greenwaste by pyrolysis on the yield of radish (Raphanus sativus var. Long Scarlet) and the soil quality of an Alfisol. Three rates of biochar (10, 50 and 100 t/ha) with and without additional nitrogen application (100 kg N/ha) were investigated. The soil used in the pot trial was a hardsetting Alfisol (Chromosol) (0-0.1 m) with a long history of cropping. In the absence of N fertiliser, application of biochar to the soil did not increase radish yield even at the highest rate of 100 t/ha. However, a significant biochar x nitrogen fertiliser interaction was observed, in that higher yield increases were observed with increasing rates of biochar application in the presence of N fertiliser, highlighting the role of biochar in improving N fertiliser use efficiency of the plant. For example, additional increase in DM of radish in the presence of N fertiliser varied from 95% in the nil biochar control to 266% in the 100 t/ha biochar-amended soils. A slight but significant reduction in dry matter production of radish was observed when biochar was applied at 10 t/ha but the cause is unclear and requires further investigation. Significant changes in soil quality including increases in pH, organic carbon, and exchangeable cations as well as reduction in tensile strength were observed at higher rates of biochar application (> 50 t/ha). Particularly interesting are the improvements in soil physical properties of this hardsetting soil in terms of reduction in tensile strength and increases in field capacity
China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen. These emissions result in the deposition of atmospheric nitrogen (N) in terrestrial and aquatic ecosystems, with implications for human and ecosystem health, greenhouse gas balances and biological diversity. However, information on the magnitude and environmental impact of N deposition in China is limited. Here we use nationwide data sets on bulk N deposition, plant foliar N and crop N uptake (from long-term unfertilized soils) to evaluate N deposition dynamics and their effect on ecosystems across China between 1980 and 2010. We find that the average annual bulk deposition of N increased by approximately 8 kilograms of nitrogen per hectare (P < 0.001) between the 1980s (13.2 kilograms of nitrogen per hectare) and the 2000s (21.1 kilograms of nitrogen per hectare). Nitrogen deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s, before the introduction of mitigation measures. Nitrogen from ammonium (NH4(+)) is the dominant form of N in bulk deposition, but the rate of increase is largest for deposition of N from nitrate (NO3(-)), in agreement with decreased ratios of NH3 to NOx emissions since 1980. We also find that the impact of N deposition on Chinese ecosystems includes significantly increased plant foliar N concentrations in natural and semi-natural (that is, non-agricultural) ecosystems and increased crop N uptake from long-term-unfertilized croplands. China and other economies are facing a continuing challenge to reduce emissions of reactive nitrogen, N deposition and their negative effects on human health and the environment.
Anthropogenic nitrogen deposition over the past half century has had a detrimental impact on temperate ecosystems in Europe and North America, resulting in soil acidification and a reduction in plant biodiversity(1,2). During the acidification process, soils release base cations, such as calcium and magnesium, neutralizing the increase in acidity. Once these base cations have been depleted, aluminium is released from the soils, often reaching toxic levels. Here, we present results from a nitrogen deposition experiment that suggests that a long legacy of acid deposition in the Western Tatra Mountains of Slovakia has pushed soils to a new threshold of acidification usually associated with acid mine drainage soils. We show that increases in nitrogen deposition in the region result in a depletion of both base cations and soluble aluminium, and an increase in extractable iron concentrations. In conjunction with this, we observe a nitrogen-deposition-induced reduction in the biomass of vascular plants, associated with a decrease in shoot calcium and magnesium concentrations. We suggest that this site, and potentially others in central Europe, have reached a new and potentially more toxic level of soil acidification in which aluminium release is superseded by iron release into soil water.
Acid weathered soils often require lime and fertilizer application to overcome nutrient deficiencies and metal toxicity to increase soil productivity. Slow-pyrolysis chicken manure biochars, produced at 350 and 700°C with and without subsequent steam activation, were evaluated in an incubation study as soil amendments for a representative acid and highly weathered soil from Appalachia. Biochars were mixed at 5, 10, 20, and 40 g kg into a Gilpin soil (fine-loamy, mixed, active, mesic Typic Hapludult) and incubated in a climate-controlled chamber for 8 wk, along with a nonamended control and soil amended with agronomic dolomitic lime (AgLime). At the end of the incubation, soil pH, nutrient availability (by Mehlich-3 and ammonium bicarbonate diethylene triamine pentaacetic acid [AB-DTPA] extractions), and soil leachate composition were evaluated. Biochar effect on soil pH was process- and rate-dependent. Biochar increased soil pH from 4.8 to 6.6 at the high application rate (40 g kg), but was less effective than AgLime. Biochar produced at 350°C without activation had the least effect on soil pH. Biochar increased soil Mehlich-3 extractable micro- and macronutrients. On the basis of unit element applied, increase in pyrolysis temperature and biochar activation decreased availability of K, P, and S compared to nonactivated biochar produced at 350°C. Activated biochars reduced AB-DTPA extractable Al and Cd more than AgLime. Biochar did not increase NO in leachate, but increased dissolved organic carbon, total N and P, PO, SO, and K at high application rate (40 g kg). Risks of elevated levels of dissolved P may limit chicken manure biochar application rate. Applied at low rates, these biochars provide added nutritional value with low adverse impact on leachate composition.
Relations among nitrogen load, soil acidification and forest growth have been evaluated based on short-term (<15 years) experiments, or on surveys across gradients of N deposition that may also include variations in edaphic conditions and other pollutants, which confound the interpretation of effects of N per se. We report effects on trees and soils in a uniquely long-term (30 years) experiment with annual N loading on an un-polluted boreal forest. Ammonium nitrate was added to replicated (N=3) 0.09 ha plots at two doses, N1 and N2, 34 and 68 kg N ha−1 yr−1, respectively. A third treatment, N3, 108 kg N ha−1 yr−1, was terminated after 20 years, allowing assessment of recovery during 10 years. Tree growth initially responded positively to all N treatments, but the longer term response was highly rate dependent with no gain in N3, a gain of 50 m3 ha−1 stemwood in N2 and a gain of 100 m3 ha−1 stemwood in excess of the control (N0) in N1. High N treatments caused losses of up to 70% of exchangeable base cations (Ca2+, Mg2+, K+) in the mineral soil, along with decreases in pH and increases in exchangeable Al3+. In contrast, the organic mor-layer (forest floor) in the N-treated plots had similar amounts per hectare of exchangeable base cations as in the N0 treatment. Magnesium was even higher in the mor of N-treated plots, providing evidence of up-lift by the trees from the mineral soil. Tree growth did not correlate with the soil Ca/Al ratio (a suggested predictor of effects of soil acidity on tree growth). A boron deficiency occurred on N-treated plots, but was corrected at an early stage. Extractable NH4+ and NO3−were high in mor and mineral soils of on-going N treatments, while NH4+ was elevated in the mor only in N3 plots. Ten years after termination of N addition in the N3 treatment, the pH had increased significantly in the mineral soil; there were also tendencies of higher soil base status and concentrations of base cations in the foliage. Our data suggest the recovery of soil chemical properties, notably pH, may be quicker after removal of the N-load than predicted. Our long-term experiment demonstrated the fundamental importance of the rate of N application relative to the total amount of N applied, in particular with regard to tree growth and C sequestration. Hence, experiments adding high doses of N over short periods do not mimic the long-term effects of N deposition at lower rates.
The effects of increased atmospheric nitrogen inputs, from both NOy and NHx, on diversity in various semi-natural and natural ecosystems are reviewed. The severity of these impacts depends on abiotic conditions (e.g. buffering capacity, soil nutrient status and soil factors that influence the nitrification potential and nitrogen immobilization rate) in the particular system. The sensitivity of fresh water ecosystems, wetlands and bogs, species-rich grasslands, heathlands and field layer of forests, all of which have conservational value, are discussed in detail.
This paper contrasts the natural and anthropogenic controls on the conversion of unreactive N2 to more reactive forms of nitrogen (Nr). A variety of data sets are used to construct global N budgets for 1860 and the early 1990s and to make projections for the global N budget in 2050. Regional N budgets for Asia, North America, and other major regions for the early 1990s, as well as the marine N budget, are presented to Highlight the dominant fluxes of nitrogen in each region. Important findings are that human activities increasingly dominate the N budget at the global and at most regional scales, the terrestrial and open ocean N budgets are essentially disconnected, and the fixed forms of N are accumulating in most environmental reservoirs. The largest uncertainties in our understanding of the N budget at most scales are the rates of natural biological nitrogen fixation, the amount of Nr storage in most environmental reservoirs, and the production rates of N2 by denitrification.
Soil fertility and leaching losses of nutrients were compared between a Fimic Anthrosol and a Xanthic Ferralsol from Central Amaznia. The Anthrosol was a relict soil from pre-Columbian settlements with high organic C containing large proportions of black carbon. It was further tested whether charcoal additions among other organic and inorganic applications could produce similarly fertile soils as these archaeological Anthrosols. In the first experiment, cowpea (Vigna unguiculata (L.) Walp.) was planted in pots, while in the second experiment lysimeters were used to quantify water and nutrient leaching from soil cropped to rice (Oryza sativa L.). The Anthrosol showed significantly higher P, Ca, Mn, and Zn availability than the Ferralsol increasing biomass production of both cowpea and rice by 38–45% without fertilization (P
The response of decomposition of litter for the dominant tree species in disturbed (pine), rehabilitated (pine and broadleaf
mixed) and mature (monsoon evergreen broadleaf) forests in subtropical China to simulated N deposition was studied to address
the following hypothesis: (1) litter decomposition is faster in mature forest (high soil N availability) than in rehabilitated/disturbed
forests (low soil N availability); (2) litter decomposition is stimulated by N addition in rehabilitated and disturbed forests
due to their low soil N availability; (3) N addition has little effect on litter decomposition in mature forest due to its
high soil N availability. The litterbag method (a total of 2880 litterbags) and N treatments: Control-no N addition, Low-N:
−5gNm−2y−1, Medium-N: −10gNm−2y−1, and High-N: −15gNm−2 y−1, were employed to evaluate decomposition. Results indicated that mature forest, which has likely been N saturated due to both long-term high N deposition in the region
and the age of the ecosystem, had the highest litter decomposition rate, and exhibited no significant positive and even some
negative response to nitrogen additions. However, both disturbed and rehabilitated forests, which are still N limited due
to previous land use history, exhibited slower litter decomposition rates with significant positive effects from nitrogen
additions. These results suggest that litter decomposition and its responses to N addition in subtropical forests of China
vary depending on the nitrogen status of the ecosystem.
Because microbial communities play a key role in carbon (C) and nitrogen (N) cycling, changes in the soil microbial community may directly affect ecosystem functioning. However, the effects of N deposition and management practices on soil microbes are still poorly understood. We studied the effects of these two factors on soil microbial biomass carbon (MBC) and community composition in Moso bamboo plantations using high-throughput sequencing of the 16S rRNA gene. Plantations under conventional (CM) or intensive management (IM) were subjected to one of four N treatments for 30 months. IM and N addition, both separately and in combination, significantly increased soil MBC while decreasing bacterial diversity. However, increases in soil MBC were inhibited when N addition exceeded 60 kg N∙ha−1∙yr−1. IM increased the relative abundances of Actinobacteria and Crenarchaeota but decreased that of Acidobacteria. N addition increased the relative abundances of Acidobacteria, Crenarchaeota, and Actinobacteria but decreased that of Proteobacteria. Soil bacterial diversity was significantly related to soil pH, C/N ratio, and nitrogen and available phosphorus content. Management practices exerted a greater influence over regulation of the soil MBC and microbial diversity compared to that of N deposition in Moso bamboo plantations.
Moso bamboo, well known for its high growth rate, is being subjected to increasing amounts of nitrogen deposition. However, how anthropogenic management practices regulate the effects of N deposition on Moso bamboo stoichiometry remains poorly understood. We observed the effects of two years of simulated N deposition (30, 60 and 90 kg N ha−1yr−1) on the foliar stoichiometry of Moso bamboo plantations under conventional management (CM) and intensive management (IM). Young bamboo had significantly greater foliar N and P concentrations and N:P ratios than mature plants (P < 0.05). IM significantly increased the foliar N concentrations of young bamboo and P concentrations of mature bamboo but decreased mature bamboo foliar N:P ratios (P < 0.05). Nitrogen increased foliar N and P concentrations in IM bamboo plantations, but the positive effects were diminished when the addition rate exceeded 60 kg N ha−1yr−1. Nitrogen increased foliar N concentrations but aggravated P deficiency in CM bamboo plantations. The positive effects of N deposition on foliar stoichiometry were influenced by management practices and bamboo growth stage. The effects of N deposition on foliar stoichiometry combined with anthropogenic management practices can influence ecosystem production, decomposition, and subsequent N and P cycles in Moso bamboo plantations.
Biochar (BC) has been shown to increase the potential for N retention in agricultural soils. However, the form of N retained and its strength of retention are poorly understood. Here, we examined if the N retained could be readily extractable by standard methods and if the amount of N retained varied with BC field ageing. We investigated soil and field-aged BC (BCaged) particles of a field experiment (sandy soil amended with BC at 0, 15, and 30 t ha−1) under two watering regimes (irrigated and rain-fed). Throughout the study, greater nitrate than ammonium retention was observed with BC addition in topsoil (0–15 cm). Subsoil (15–30 cm) nitrate concentrations were reduced in BC treatments, indicating reduced nitrate leaching (standard 2 mol L−1 KCl method). The mineral-N release of picked BCaged particles was examined with different methods: standard 2 mol L−1 KCl extraction; repeated (10×) extraction in 2 mol L−1 KCl at 22 ± 2°C and 80°C (M0); electro-ultrafiltration (M1); repeated water + KCl long-term shaking (M2); and M2 plus one repeated shaking at 80°C (M3). Nitrate amounts captured by BCaged particles were several-fold greater than those in the BC-amended soil. Compared with M0, standard 2 mol L−1 KCl or electro-ultrafiltration extractions retrieved only 13 and 30% of the total extractable nitrates, respectively. Our results suggest that “nitrate capture” by BC may reduce nitrate leaching in the field and that the inefficiency of standard extraction methods deserves closer research attention to decipher mechanisms for reactive N management.
Are the health and productivity of Sweden’s forests at risk from too much nitrogen (N) from acid deposition? Twenty years ago we assessed the evidence available for several aspects of this question (Binkley and Högberg, 1997). We found little evidence for risks other than potential shifts in ground flora, but concerns continued to arise across Europe and elsewhere. We took advantage of two decades of accumulated evidence to re-evaluate whether Swedish forests are threatened by N deposition. During this time, N deposition declined by about 25% across the southern half of Sweden, and sulfur deposition declined by more than half. The growth rates of forests across the country continued the long-term trend of increasing by about 1–1.5% annually; average growth rates are now about 20–25% greater than in the mid-1990s. Forest soils often acidify by about 0.5–1.5 pH units during a rotation, but some evidence indicated that acidification may have occurred beyond this age-related pattern. Any average change in soil pH across the country appeared to relate more strongly to increases in carbon concentrations rather than cation leaching and declining base saturation. No evidence of N saturation (with outputs matching inputs) has been reported in Sweden, and nitrogen-limitation remains widespread. Fertilization with elements other than N generally does not increase growth unless N is also added, especially on mineral soils. Long-term fertilization experiments demonstrated that growth responses depended heavily on the dose rate of N application, not just cumulative totals. Repeated low rates of addition (20–50 kg N ha−1 yr−1) provided greater growth increases per kg N added than higher rates, illustrating that the possible impacts of N deposition could not be reliably gauged by shorter-term experiments with unrealistically high dose rates. The composition of ground flora appeared to be sensitive to N additions, in studies across geographic gradients of N deposition and with high rates of N fertilization. Any long-term effects of N deposition on ground flora may be difficult to separate from long-term changes in stand structure and growth. Aluminum toxicity concerns do not appear to be supported by evidence, and liming generally does not increase forest growth. We discuss broader implications that arise from this assessment, including approaches to evaluating support for assumptions, the varying quality of types of evidence, and in some cases the irreducibility of uncertainty about elucidating cause-and-effect responses in complex forest systems.
Biochar application to cropland has been recommended as a strategy to reduce increasing atmospheric CO2 concentrations and mitigate climate change. However, the direction and magnitude of responses of greenhouse gas (GHG) fluxes to biochar application to cropland remain unclear. Our meta-analysis of 296 observations across 61 studies for the first time quantitatively estimated the effects of biochar amendment on fluxes of three GHGsCO2, N2O, and CH4. The results showed that biochar application led to a significant change in soil GHGs emissions: in general, 19% for CO2, −16% for N2O (P < 0.05), but no pronounced change in CH4 emissions; in paddy, −5% for CO2, −20% for N2O, but +19% for CH4 (P < 0.05); in upland, −18% for N2O, +12% for CO2, and high uncertainty for CH4. The responses of soil GHG fluxes to biochar application were regulated mainly by experiment length, biochar application rate, biochar properties, providing a new perspective for more comprehensive understanding on biochar. The biochar derived from husk was recommended to apply to cropland with an application rate of 20–30 t·ha−1.