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1.
该文评估了双季稻田施用生物炭的温室气体排放和固碳及经济效益。采用生命周期（life cycle assessment,LCA）方法核算了生物炭原料收集与运输、生物炭生产、运输和撒播以及避免秸秆燃烧等过程中的温室气体排放和土壤碳储量;采用静态箱-气相色谱法监测了不同生物炭施入量在4 a 8个生育期的稻田CH4和N2O排放量;计算了不同生物炭施入量处理的净温室气体排放量和减排百分比。水稻生长季温室气体排放结果显示,CK处理（不添加生物炭）、BC1处理（5 t/hm2）、BC2处理（10 t/hm2）、BC3处理（20 t/hm2）的4 a田间温室气体排放总量分别为19.5、15.6、16.1、12.4 t/hm2,BC1、BC2和BC3处理相对CK处理的总减排百分比分别为19.70%、17.46%和36.40%。综合生物炭全生命周期各阶段温室气体排放,CK、BC1、BC2和BC3处理的4 a总净排放量分别为19.5、20.3、10.9、4.2 t/hm2,BC1处理的4a净排放相对CK处理增加4.3%,BC2和BC3处理的4 a净排放相对CK处理分别减少了44.0%、78.6%。3个生物炭用量中,生物炭施用量越低,经济效益越好。稻田施用生物炭能够降低其温室气体排放;全生命周期评估结果表明中量和高量生物炭能够起到减排效果,高量生物炭减排效果最好;经济效益分析结果表明随着生物炭施用量增加,经济效益降低。 相似文献
2.
The application of biochar produced from wood and crop residues, such as sawdust, straw, sugar bagasse and rice hulls, to highly weathered soils under tropical conditions has been shown to influence soil greenhouse gas (GHG) emissions. However, there is a lack of data concerning GHG emissions from soils amended with biochar derived from manure, and from soils outside tropical and subtropical regions. The objective of this study was to quantify the effect on emissions of carbon dioxide (CO 2), nitrous oxide (N 2O) and methane (CH 4) following the addition, at a rate of 18 t ha −1, of two different types of biochar to an Irish tillage soil. A soil column experiment was designed to compare three treatments ( n = 8): (1) non-amended soil (2) soil mixed with biochar derived from the separated solid fraction of anaerobically digested pig manure and (3) soil mixed with biochar derived from Sitka Spruce ( Picea sitchensis). The soil columns were incubated at 10 °C and 75% relative humidity, and leached with 80 mL distilled water, twice per week. Following 10 weeks of incubation, pig manure, equivalent to 170 kg nitrogen ha −1 and 36 kg phosphorus ha −1, was applied to half of the columns in each treatment ( n = 4). Gaseous emissions were analysed for 28 days following manure application. Biochar addition to the soil increased N 2O emissions in the pig manure-amended column, most likely as a result of increased denitrification caused by higher water filled pore space and organic carbon (C) contents. Biochar addition to soil also increased CO 2 emissions. This was caused by increased rates of C mineralisation in these columns, either due to mineralisation of the labile C added with the biochar, or through increased mineralisation of the soil organic matter. 相似文献
3.
PurposeThis study focused on the effects and mechanisms of biochar amendment to Cd-contaminated soil on the uptake and translocation of Cd by rice under flooding conditions. Materials and methodsPot and batch experiments were conducted using Cd-contaminated soil collected from a field near an ore mining area and a cultivar of Oryza sativa ssp. indica. Biochar derived from rice straw under anaerobic conditions at 500 °C for 2 h was mixed with the soil at the rate of 0, 2.5, and 5%. Results and discussionThe application of 5% biochar reduced CaCl2-extractable soil Cd by 34% but increased Cd concentration in brown rice by 451%. Biochar amendment decreased water-soluble Fe2+ in soils and formation of Fe plaques on roots and weakened the Fe2+-Cd2+ competition at adsorption sites on the root surface. Biochar increased water-soluble Cd in the soil and consequently Cd uptake by rice roots by releasing water-soluble Cl?. Biochar application also reduced the proportion of cell wall-bound Cd in the root, which caused easier Cd translocation from the cortex to the stele in the root and up to the shoot. ConclusionsRice straw biochar (with high concentration of water-soluble Cl?) reduced CaCl2-extractable soil Cd but increased Cd concentration in rice under flooding condition. 相似文献
4.
PurposeBiochar has shown to be a great product to control the bioavailability of potentially hazardous elements (PHE) in contaminated soils. Despite the advantages associated with the application of biochar in agricultural soils, relatively few studies have focused on the effects of biochar amendments on soil chemical properties, accumulation of arsenic, cadmium, zinc, and lead in rice tissues, and their availability in soil systems. Materials and methodsThe field experiment was conducted at the paddy soils in Hunan Province, China. The soil texture was sandy clay loam. Wheat-derived biochar was applied once to the experimental plots at the rates of 0, 10, 20, 30 and 40 t ha?1, and referenced as A0, A10, A20, A30, and A40, respectively. For PHE determination, soil samples and plant samples were digested with a mixed solution of HCl:HNO3 (4:1, V:V) and HCl:HClO4 (4:1, V:V), respectively, and the arsenic, cadmium, zinc, and lead in the digest solution were measured by ICP-MS (Thermo Fisher Scientific, USA). The soil available fraction of PHE (arsenic, cadmium, zinc, and lead) was extracted by diethylenetriamine pentaacetic acid (DTPA) and measured by inductively ICP-MS. Results and discussionBiochar amendment increased chemical properties of soil organic matter, pH, electrical conductivity, cation exchange capacity, nitrate nitrogen, and available phosphorus. Soil DTPA extractable arsenic, cadmium, zinc, and lead concentrations were significantly reduced. Arsenic, cadmium, zinc, and lead in rice shoots, and arsenic, cadmium, and zinc in roots significantly decreased after amendment. Concentrations in rice tissues positively and negatively correlated with the soil available fraction of PHE and soil chemical properties, respectively. Soil electrical conductivity negatively correlated with the soil available fraction of PHE. Concentrations of arsenic, zinc, cadmium, and lead in rice roots declined relative to increases of cation exchange capacity (arsenic, zinc), available phosphorus (cadmium), and nitric nitrogen (lead) content. Similar relationships were observed between cation exchange capacity and PHE in shoots. ConclusionsBiochar creates avoidance of PHE through regulating chemical properties through biochar sorption capacity. Cation exchange capacity, available phosphorus, and nitric nitrogen were the principle factors affecting roots uptake of arsenic, zinc, cadmium, and lead. Biochar soluble salts could decline availability of metals/metalloids in soils through precipitation. Wheat-derived biochar application is an alternative safe product to immobilize PHE in rice paddy soils by restricting the risk of PHE. 相似文献
5.
Impacts of biochar addition on nitrous oxide (N 2O) and carbon dioxide (CO 2) emissions from paddy soils are not well documented. Here, we have hypothesized that N 2O emissions from paddy soils could be depressed by biochar incorporation during the upland crop season without any effect
on CO 2 emissions. Therefore, we have carried out the 60-day aerobic incubation experiment to investigate the influences of rice
husk biochar incorporation (50 t ha −1) into two typical paddy soils with or without nitrogen (N) fertilizer on N 2O and CO 2 evolution from soil. Biochar addition significantly decreased N 2O emissions during the 60-day period by 73.1% as an average value while the inhibition ranged from 51.4% to 93.5% ( P < 0.05–0.01) in terms of cumulative emissions. Significant interactions were observed between biochar, N fertilizer, and
soil type indicating that the effect of biochar addition on N 2O emissions was influenced by soil type. Moreover, biochar addition did not increase CO 2 emissions from both paddy soils ( P > 0.05) in terms of cumulative emissions. Therefore, biochar can be added to paddy fields during the upland crop growing
season to mitigate N 2O evolution and thus global warming. 相似文献
6.
Biochar application to soil has significant potential as a climate change mitigation strategy, due to its recalcitrant C content and observed effect to suppress soil greenhouse gas emissions such as nitrous oxide (N 2O). Increased soil aeration following biochar amendment may contribute to this suppression.Soil cores from a Miscanthus X. giganteus plantation were amended with hardwood biochar at a rate of 2% dry soil weight (22 t ha −1). The cores were incubated at three different temperatures (4, 10 and 16 °C) for 126 days, maintained field moist and half subjected to periodic wetting events. Cumulative N 2O production was consistently suppressed by at least 49% with biochar amendment within 48 h of wetting at 10 and 16 °C. We concluded that hardwood biochar suppressed soil N 2O emissions following wetting at a range of field-relevant temperatures over four months. We hypothesised that this was due to biochar increasing soil aeration at relatively high moisture contents by increasing the water holding capacity (WHC) of the soil; however, this hypothesis was rejected.We found that 5% and 10% biochar amendment increased soil WHC. Also, 10% biochar amendment decreased bulk density of the soil. Sealed incubations were performed with biochar added at 0–10 % of dry soil weight and wetted to a uniform 87% WHC (78% WFPS). Cumulative N 2O production within 60 h of wetting was 19, 19, 73 and 98% lower than the biochar-free control in the 1, 2, 5 and 10% biochar treatments respectively. We conclude that high levels of biochar amendment may change soil physical properties, but that the enhancement of soil aeration by biochar incorporation makes only a minimal contribution to the suppression of N 2O emissions from a sandy loam soil. We suggest that microbial or physical immobilisation of NO 3− in soil following biochar addition may significantly contribute to the suppression of soil N 2O emissions. 相似文献
7.
Purpose Directly returning straw back to the paddy field would significantly accelerate methane (CH 4) emission, although it may conserve and sustain soil productivity. The application of biochar (biomass-derived charcoal) in soil has been proposed as a sustainable technology to reduce methane (CH 4) emission and increase crop yield. We compared the effects of either biochar or rice straw addition with a paddy field on CH 4 emission and rice yield. Materials and methods A 2-year field experiment was conducted to investigate a single application of rice straw biochar (SC) and bamboo biochar (BC) (at 22.5 t ha ?1) in paddy soil on CH 4 emission and rice yield as compared with the successive application (6 t ha ?1) of rice straw (RS). Soil chemical properties and methanogenic and CH 4 oxidation activities in response to the amendment of biochar and rice straw were monitored to explain possible mechanism. Results and discussion SC was more efficient in reducing CH 4 emission from paddy field than BC. Incorporating SC into paddy field could decrease CH 4 emission during the rice growing cycle by 47.30 %–86.43 % compared with direct return of RS. This was well supported by the significant decrease of methanogenic activity in paddy field with SC. In comparison to a non-significant increase with BC or RS application, rice yield was significantly raised with SC amendment by 13.5 % in 2010 and 6.1 % in 2011. An enhancement of available K and P and an improvement in soil properties with SC amendment might be the main contributors to the increased crop yield. Conclusions These results indicated that conversion of RS into biochar instead of directly returning it to the paddy field would be a promising method to reduce CH 4 emission and increase rice yield. 相似文献
8.
Abstract The scenarios for conventional puddling and no-tilling rice ( Oryza sativa L.) cultivation were compared in terms of greenhouse gas (GHG) emissions from paddy fields, fuel consumption and manufacturing of invested materials using a life cycle inventory (LCI) based analysis. Only the differences between the scenarios were examined. The no-tilling scenario omitted both tilling and puddling, but included spraying of a non-selective herbicide and used a transplanter equipped with a rotor. Fertilization was a basal single application of controlled release fertilizer in nursery boxes for all scenarios. After transplanting, there were no differences in machine work, invested materials or rice yields between the scenarios. The no-tilling scenario saved on fuel consumption, totaling carbon dioxide (CO 2) output of 42 kg ha ?1, which was equal to the 6% reported GHG emissions from fuel consumption by operating machines during rice production in Japan. Methane (CH 4) and nitrous oxide (N 2O) emissions from the paddy fields were also monitored and compared for the scenarios. Methane has a major effect on global warming as part of the GHG emitted from paddy fields. The cumulative CH 4 emissions from the no-tilling cultivation were 43% lower than those from conventional puddling cultivation because the plow layer was more oxidative in no-tilling cultivation. The N 2O emissions were not significantly different between the cultivation scenarios. There were no significant differences in soil respiration, soil carbon contents or straw yields between the cultivation scenarios. The effect of tillage on CO 2 flux in the paddy fields did not seem to be significant in this study. Consequently, the GHG emissions from the no-tilling field counted as CO 2 using global warming potentials were 1,741 kg CO 2 ha ?1 lower than those from the conventional puddling field. In conclusion, no-tilling rice cultivation has the potential to save 1,783 kg CO 2 ha ?1 calculated using the sum of fuel consumption and GHG emissions from paddy fields. No-tilling rice cultivation is considered to be environmentally friendly agriculture with respect to reducing GHG emissions. 相似文献
9.
Understanding and improving environmental quality by reducing soil nutrient leaching losses, sequestering carbon (C), reducing greenhouse gas (GHG) emissions, and enhancing crop productivity in highly weathered or degraded soils have always been the goals of agroecosystem researchers and producers. Biochar production and soil incorporation strategies have been recently proposed to help attain these goals. However, the effect of such approaches on soil GHG fluxes is highly uncertain and needs to be further assessed before biochar can be used on a large scale. In addition, the duration of these GHG reductions is not known and is of pivotal importance for the inclusion of biochar in climate abatement strategies. In a field trial cultivated with Chinese cabbage (Brassica campestris ssp. pekinensis) and radish ( Daucus carota L. var. Sativa Hoffm), rapeseed ( Brassica campestris L.) and maize ( Zea mays L.) straw-derived biochar was added to the soil at rates of 0, 26, 64 and 128 t ha ?1, in the whole growing season (October 2011–March 2012) to monitor the effect of treatments on soil GHG production/consumption and soil quality 16 months after biochar addition. The results showed that biochar amendment increased soil pH, nitrate nitrogen content, available phosphorus content and soil water content, but decreased soil bulk density. In biochar-treated plots, soil carbon dioxide (CO 2) fluxes were from 20.1 to 87.0% higher than in the control. Soil methane (CH 4) uptakes were increased significantly, by 33.2 and 80.1%, between the biochar amendment at the rate of 64 and 128 t ha ?1 and the control. Soil nitrous oxide (N 2O) fluxes showed no significant difference between biochar amendment and the control. Overall only the CH 4 uptake-promoting effect continued into the long term, 16 months after biochar incorporation. This study demonstrates that the beneficial effects of biochar addition might first come through soil quality improvement and carbon sequestration, rather than through effects on the repression of soil C mineralization or the nitrogen cycle. 相似文献
10.
PurposeForests play a critical role in terrestrial ecosystem carbon cycling and the mitigation of global climate change. Intensive forest management and global climate change have had negative impacts on the quality of forest soils via soil acidification, reduction of soil organic carbon content, deterioration of soil biological properties, and reduction of soil biodiversity. The role of biochar in improving soil properties and the mitigation of greenhouse gas (GHG) emissions has been extensively documented in agricultural soils, while the effect of biochar application on forest soils remains poorly understood. Here, we review and summarize the available literature on the effects of biochar on soil properties and GHG emissions in forest soils. Materials and methodsThis review focuses on (1) the effect of biochar application on soil physical, chemical, and microbial properties in forest ecosystems; (2) the effect of biochar application on soil GHG emissions in forest ecosystems; and (3) knowledge gaps concerning the effect of biochar application on biogeochemical and ecological processes in forest soils. Results and discussionBiochar application to forests generally increases soil porosity, soil moisture retention, and aggregate stability while reducing soil bulk density. In addition, it typically enhances soil chemical properties including pH, organic carbon stock, cation exchange capacity, and the concentration of available phosphorous and potassium. Further, biochar application alters microbial community structure in forest soils, while the increase of soil microbial biomass is only a short-term effect of biochar application. Biochar effects on GHG emissions have been shown to be variable as reflected in significantly decreasing soil N2O emissions, increasing soil CH4 uptake, and complex (negative, positive, or negligible) changes of soil CO2 emissions. Moreover, all of the aforementioned effects are biochar-, soil-, and plant-specific. ConclusionsThe application of biochars to forest soils generally results in the improvement of soil physical, chemical, and microbial properties while also mitigating soil GHG emissions. Therefore, we propose that the application of biochar in forest soils has considerable advantages, and this is especially true for plantation soils with low fertility. 相似文献
11.
To evaluate the benefits of application of biochar to coastal saline soil for climate change mitigation, the effects on soil organic carbon (SOC), greenhouse gases (GHGs) and crop yields were investigated. Biochar was applied at 16 t ha ?1 to study its effects on crop growth (Experiment I). The effects of biochar (0, 3.2, 16 and 32 t ha ?1) and corn stalk (7.8 t ha ?1) on SOC and GHGs were studied using 13C stable isotope technology and a static chamber method, respectively (Experiment II). Biochar increased grain mass per plant of the wheat by 27.7% and increased SOC without influencing non‐biochar SOC. On average, 92.3% of the biochar carbon and 16.8% of corn‐stalk carbon were sequestered into the soil within 1 year. The cumulative emissions of CO 2, CH 4 and N 2O were not affected significantly by biochar but cornstalk application increased N 2O emissions by 17.5%. The global warming mitigation potential of the biochar treatments (?3.84 to ?3.17 t CO 2‐eq. ha ?1 t ?1 C) was greater than that of the corn stalk treatment (?0.11 t CO 2‐eq ha ?1 t ?1 C). These results suggest that biochar application improves saline soil productivity and soil carbon sequestration without increasing GHG emissions. 相似文献
12.
ABSTRACT Biochar application and alternate wetting and drying (AWD) are emerging as promising technologies recommended for reducing CH 4 emissions and water consumption in rice cultivation. In this study, we hypothesized that both technologies could be practiced in combination and this could further reduce CH 4 emissions and water consumption when compared to practicing alone. The effects of biochar application and its co-application with chemical fertilizer or compost under conventional or AWD water management on CH 4 emissions, productivity of rice, water use, and SOC stock, as well as cost and income were investigated. The experiment was carried out in an irrigated paddy field in the central plain of Thailand during both in the wet and dry seasons. Relative to control (CT), biochar application (BI), its co-application with compost (BC) or chemical fertilizer (BF) reduced seasonal CH 4 emissions by 40.6%, 29.5%, and 12.3%, respectively. BI and BC significantly ( p < 0.05) reduced grain yield by 19.9% and 10.8%, respectively, while BF significantly increased grain yield by 3.70%. In addition, BI, BC, and BF significantly enhanced soil organic carbon (SOC) stock by 21.2%, 21.4%, and 18.3%, respectively. Compared to the CT, higher production costs were found in BC and BF, but the farmer’s net incomes were also higher in BF because of its higher grain yield. On the other hand, water management in all amendment treatments under AWD was resulted in the reduction of CH 4 emissions by the average of 18.8% as compared to the conventional system. AWD decreased rice yield by an average of 2.29%. It significantly reduced irrigation water use by an average of 11.9%, resulting in reducing production cost for water pumping. The results show that the practice that combined biochar application, AWD and chemical fertilizer are feasible for CH 4 emission mitigation, SOC stock increase and irrigation water saving without significant effects on yield and farmer income. 相似文献
13.
PurposeBiochar has agronomic potential but currently is too expensive for widespread adoption. New methodologies are emerging to reduce the cost such as enriching biochar with nutrients that match crops and soil requirements. However, the effects of biochar-based fertilisers on plant yield and soil nutrient availability have not been widely examined. This study investigated the effects of a novel organo-mineral biochar fertiliser in comparison to organic and commercial biochar fertiliser on ginger (Zingiber officinale Canton). Materials and methodsThere were four treatments: (1) commercial organic fertiliser (5 t ha?1), as the control; (2) commercial biochar-based fertiliser (5 t ha?1); (3) organo-mineral biochar fertiliser at low rate (3 t ha?1); and (4) organo-mineral biochar fertiliser at high rate (7.5 t ha?1). A replicated pot trial was established with black dermosol soil and ten replicate pots for each treatment. Ginger was planted and grown for 30 weeks. Plant growth, biomass, foliar nutrients and water extractable soil nutrients including phosphorus (P), potassium (K) and calcium (Ca) were examined. Results and discussionHigh rate organo-mineral biochar fertiliser increased soil P and K availability at week 30 (harvest) after planting, compared to all other treatments and low rate organo-mineral biochar fertiliser performed similarly to the organic control for P and K. High rate organo-mineral biochar fertiliser increased total foliar nutrient content at week 30 in P, K and Ca compared to commercial biochar fertiliser. High rate organo-mineral biochar fertiliser improved the commercial value of ginger (+?36%) due to a shift in the proportion of higher grade rhizomes. Low rate organo-mineral biochar fertiliser plants displayed similar yield, total dry and aboveground biomass to commercial organic fertiliser. Commercial biochar fertiliser had significantly lower biomass measures compared with other treatments as the rate applied had lower nutrient concentrations. ConclusionsOur results show organo-mineral biochar fertilisers could be substituted for commercial organic fertilisers at low rates to maintain similar yield or applied at high rates to increase commercial value where economically feasible. 相似文献
14.
PurposeBiochar usually has a large specific surface area, and due to this, it increases the sorption capacity of the soil where it was applied. The objectives of this study were to (i) quantify the effects of biochar and biochar in combination with N fertilizer on the soil sorption parameters and (ii) quantify the effects of soil organic matter on the sorption parameters after application of biochar with and without N fertilizer. Materials and methodsThe experiment was established on Haplic Luvisol at the locality of Dolná Malanta (Slovakia) in 2014. The soil samples were collected once a month from the depth 0–0.2 m during 2014 to 2016. The field experiment included three rates of biochar application (B0?=?no biochar, B10?=?biochar at the rate of 10 t ha?1, B20?=?biochar at the rate of 20 t ha?1) and three levels of N fertilization (N0?=?no nitrogen, N40?=?nitrogen at the rate of 40 kg ha?1, N80?=?nitrogen at the rate of 80 kg ha?1). Results and discussionOverall, the decrease of the average values of hydrolytic acidity due to biochar and biochar combined with N fertilization resulted on average in an increase of sum of basic cation (SBC), cation exchange capacity (CEC), and sorption capacity of soil organic matter (CECSOM) in all treatments. However, this effect was the most intensive in B10N40. Despite the fact that the average values of sorption parameters improved, its dynamics during the investigated period were different. A significant decrease in CEC was observed from 2014 to 2016 in all treatments, except B0N0 and B10N0. A stable trend in CECSOM was observed only in B10N40. Humic substances and humic acids had a statistically significant positive effect on the SBC, CEC, and CECSOM only in B20N0 treatment. Negative correlations between the above mentioned parameters were observed in B10N80 treatment. ConclusionsWe conclude that the application of biochar and biochar combined with N fertilization had a positive influence on sorption parameters. However, its effects on SBC, CEC, and CECSOM decreased over time after its application. 相似文献
15.
PurposeThe environmental benefits of biochar application, ranging from improvements in crop yield to global change mitigation, have been extensively studied in the last decade. However, such benefits have not been profusely demonstrated under a Mediterranean climate and still less in combination with high pH soils. In our study, the short to medium effects of biochar application on a soil-plant system under Mediterranean conditions in an alkaline soil were assessed. Material and methodsBarley plants were grown in field mesocosms during three agronomical years at three biochar addition rates (0, 5, and 30 t ha?1). Related to soil, different physicochemical parameters were analyzed as well as microbial respiration, biomass, and functional diversity. In the plant domain, in vivo ecophysiology variables such as leaf transpiration rate, stomatal conductance, and photosynthesis rate were determined while photosynthetic pigment content and soluble protein concentrations were measured in the laboratory. Additionally, crop yield and nutrient composition were also analyzed. The soil-plant connection was investigated by the N content ratio in both fractions establishing the nitrogen efficiency in the system. Results and discussionThe highest rate of biochar amendment enhanced soil moisture and electrical conductivity combined with an increase of SO42?, Cl?, Mg2+, and K+, and decrease of NO3? and HPO4?. Notable variations regarding nutrition and moisture were induced in this Mediterranean alkaline soil after biochar addition although pH remained stable. Contrastingly, there were no major effects on microbial activity, but a lower abundance of the nosZ functional gene was found. Similarly, plant parameters were unaffected regarding chemical composition and ecophysiology although biochar induced a higher efficiency in the plant nitrogen uptake without increasing crop yield. ConclusionsBiochar addition at the highest rate (30 t ha?1) reduced soil-soluble nitrate although N uptake by the plant remained invariable, in turn coupled to no effects on crop productivity. Our study showed that, in a Mediterranean agroecosystem, a wood biochar produced by gasification was unable to increase crop yield, but enhanced soil water retention, decreased the need for N fertilization, and decreased soil-soluble nitrate concentrations, something that could help to mitigate the excessive nitrate levels associated with over-fertilization. 相似文献
16.
Biochar application to arable soils could be effective for soil C sequestration and mitigation of greenhouse gas (GHG) emissions. Soil microorganisms and fauna are the major contributors to GHG emissions from soil, but their interactions with biochar are poorly understood. We investigated the effects of biochar and its interaction with earthworms on soil microbial activity, abundance, and community composition in an incubation experiment with an arable soil with and without N-rich litter addition. After 37 days of incubation, biochar significantly reduced CO 2 (up to 43 %) and N 2O (up to 42 %), as well as NH 4 +-N and NO 3 ?-N concentrations, compared to the control soils. Concurrently, in the treatments with litter, biochar increased microbial biomass and the soil microbial community composition shifted to higher fungal-to-bacterial ratios. Without litter, all microbial groups were positively affected by biochar × earthworm interactions suggesting better living conditions for soil microorganisms in biochar-containing cast aggregates after the earthworm gut passage. However, assimilation of biochar-C by earthworms was negligible, indicating no direct benefit for the earthworms from biochar uptake. Biochar strongly reduced the metabolic quotient qCO 2 and suppressed the degradation of native SOC, resulting in large negative priming effects (up to 68 %). We conclude that the biochar amendment altered microbial activity, abundance, and community composition, inducing a more efficient microbial community with reduced emissions of CO 2 and N 2O. Earthworms affected soil microorganisms only in the presence of biochar, highlighting the need for further research on the interactions of biochar with soil fauna. 相似文献
17.
As global warming intensifies, the soil environment in middle to high latitudes will undergo more extensive and frequent freeze–thaw cycles (FTCs), which will significantly affect the carbon and nitrogen cycles of soil ecosystems and aggravate greenhouse gas (GHG) emissions. Biochar can increase soil organic carbon storage and mitigate climate change. To effectively control GHG emissions, soil supplemented with biochar at different application rates (0%, 2%, 4% and 6% [w/w]) under different numbers of FTCs (0, 3, 6, 9, and 12) was selected as the research object. The soil GHG emission characteristics in different experimental treatments and their relationships with soil physical and chemical properties were determined. Our results showed that N 2O and CO 2 emissions were promoted during FTCs, with values of 3.13–50.37 and 16.22–135.50 μg m −2 h −1, respectively. The order of N 2O and CO 2 emissions with respect to biochar application rate was as follows: 2% > 0% > 4% > 6%. CH 4 emissions were negative during FTCs, varying from −1.62 to −10.59 μg m −2 h −1, and negative CH 4 emissions were promoted by biochar. Correlation analysis showed that N 2O, CO 2 and CH 4 emissions were significantly correlated with pH, soil moisture and soil organic matter (SOM), total nitrogen (TN) and –N contents ( p < .01). The conceptual path model demonstrated that GHG emissions were significantly influenced by FTCs, moisture, SOM and biochar application rate. Our results indicate that the effects of FTCs on GHG emissions were greater than those of biochar application. Biochar application rates of 4% or 6% should be considered in the future to reduce soil GHG emissions in the black soil region of Northeast China. Our results can help provide a theoretical basis and effective strategy to reduce soil GHG emissions during FTCs in seasonally frozen regions. 相似文献
18.
Biochar application can reduce global warming via carbon (C) sequestration in soils. However, there are few studies investigating its effects on greenhouse gases in rice ( Oryza sativa L.) paddy fields throughout the year. In this study, a year-round field experiment was performed in rice paddy fields to investigate the effects of biochar application on methane (CH 4) and nitrous oxide (N 2O) emissions and C budget. The study was conducted on three rice paddy fields in Ehime prefecture, Japan, for 2 years. Control (Co) and biochar (B) treatments, in which 2-cm size bamboo biochar (2 Mg ha ?1) was applied, were set up in the first year. CH 4 and N 2O emissions and heterotrophic respiration (Rh) were measured using a closed-chamber method. In the fallow season, the mean N 2O emission during the experimental period was significantly lower in B (67 g N ha ?1) than Co (147 g N ha ?1). However, the mean CH 4 emission was slightly higher in B (2.3 kg C ha ?1) than Co (1.2 kg C ha ?1) in fallow season. The water-filled pore space increased more during the fallow season in B than Co. In B, soil was reduced more than in Co due to increasing soil moisture, which decreased N 2O and increased CH 4 emissions in the fallow season. In the rice-growing season, the mean N 2O emission tended to be lower in B (?104 g N ha ?1) than Co (?13 g N ha ?1), while mean CH 4 emission was similar between B (183 kg C ha ?1) and Co (173 kg C ha ?1). Due to the C release from applied biochar and soil organic C in the first year, Rh in B was higher than that in Co. The net greenhouse gas emission for 2 years considering biochar C, plant residue C, CH 4 and N 2O emissions, and Rh was lower in B (5.53 Mg CO 2eq ha ?1) than Co (11.1 Mg CO 2eq ha ?1). Biochar application worked for C accumulation, increasing plant residue C input, and mitigating N 2O emission by improving soil environmental conditions. This suggests that bamboo biochar application in paddy fields could aid in mitigating global warming. 相似文献
19.
黏土中施加生物炭可改变土体的孔隙结构。生物炭掺量和干密度均会对土体的渗透系数产生影响,准确确定生物炭-黏土混合土的渗透系数对满足填埋场上覆层的功能需求就显得格外重要。采用自主研发设计的柔性壁水-气联合渗透测试装置,测定不同生物炭掺量和干密度的生物炭-黏土混合土的饱和渗透系数和渗气系数,得到生物炭掺量、干密度与渗气系数和渗水系数间的关系曲线。建立生物炭掺量和干密度双变化条件下的渗气渗水函数,并通过验证组验证该函数的适用性。研究结果表明：在干密度较小时,对比纯黏土的渗水率,添加5%、10%、15%和20%生物炭处理后的土样渗水系数 kw值分别为8.25×10 -17、8.89×10 -17、10.40×10 -17和18.25×10 -17 m 2,掺20%生物炭土样的渗透率增加了将近一个数量级。渗气渗水函数基于易测定的渗气率作为自变量,同时又考虑了干密度和生物炭掺量的影响,能快速、准确地确定土样的渗水系数。结合验证组试验得出,利用该函数计算得到的渗水系数和试验实测值吻合程度较好,表明该函数具有一定的适用性。本研究结果可为快速、准确确定渗水系数,定量描述非饱和土孔隙中水气运动之间的相互影响提供理论支撑。 相似文献
20.
PurposePaddy fields are an important source of nitrous oxide (N2O) emission. The application of biochar or the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) to paddy soils have been proposed as technologies to mitigate N2O emissions, but their mechanisms remain poorly understood. MethodsAn experiment was undertaken to study the combined and individual effects of biochar and DMPP on N2O emission from a paddy field. Changes in soil microbial community composition were investigated. Four fertilized treatments were established as follows: fertilizer only, biochar, DMPP, and biochar combined with DMPP; along with an unfertilized control. ResultsThe application of biochar and/or DMPP decreased N2O emission by 18.9–39.6% compared with fertilizer only. The combination of biochar and DMPP exhibited higher efficiency at suppressing N2O emission than biochar alone but not as effective as DMPP alone. Biochar promoted the growth of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), while DMPP suppressed AOB and increased AOA. Applying biochar with DMPP reduced the impact of DMPP on AOB. The nirS-/nirK- denitrifiers were decreased and nosZ-N2O reducers were increased by DMPP and the combination of DMPP and biochar. The abundance of the nirK gene was increased by biochar at the elongation and heading stages of rice development. Compared with fertilizer only, the application of biochar and/or DMPP promoted the abundance of nosZ genes. ConclusionThese results suggest that applying biochar and/or DMPP to rice paddy fields is a promising strategy to reduce N2O emissions by regulating the dynamics of ammonia oxidizers and N2O reducers. 相似文献
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