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1.
Solar vegetable greenhouse soils show low soil organic carbon content and thus also low rates of soil respiration. Processing vegetable residues to biochar and mixing biochar with maize straw might improve soil respiration and increase soil organic carbon stocks, while preventing the spread of soil-borne diseases carried by vegetable residues. In an incubation experiment, we tested how additions of maize straw (S) and biochar (B) added in varying ratios (100S, 75S25B, 50S50B, 25S75B, 100B and 0S0B (control)) affect soil respiration and fraction of added C remaining in soil. Daily CO2 emissions were measured over 60 days incubation, the natural abundance of 13C in soil and in the added biochar and maize straw were analysed. Our result shows that (a) soil CO2 emissions were significantly increased compared to soil without the straw additions, while addition of biochar only decreased soil respiration; (b) cumulative CO2 emissions decreased with increasing ratio of added biochar to maize straw; (c) the abundance of soil 13C was significant positively correlated with cumulative CO2 emissions, and thus with the ratio of straw addition. Our results indicate that incorporation of maize straw in greenhouse soils is a meaningful measure to increase soil respiration and to facilitate greenhouse atmosphere CO2 limitation while producing vegetables. On the other hand, additions of biochar from vegetable residues will increase soil organic carbon concentration. Therefore, the simultaneous application of maize straw and biochar obtained from vegetable residues is an effective option to maintain essential soil functions for vegetable production in sunken solar greenhouses.  相似文献   

2.
During 4 months from 70 to 79% of the carbon of added glucose, cellulose, and Leuconostoc dextranicus polysaccharide had evolved as CO2 from normal agricultural soils of Chile and California. The presence or additions of allophanic material reduced losses of glucose C by about 25% and of the C of the polysaccharides by 36–65%. From wheat straw, the polysaccharide fraction of wheat straw, and protein, C losses were 60, 78 and 67%, respectively, in the normal soils. Reductions related to allophane were about 41–67%. For a number of microbial cells, C loss reductions due to allophanic materials ranged from 31 to 55%. Carbon losses from catechol and ferulic acid were more related to reactivities of the phenols, the soil pH, and the organic matter content of the soil than to the presence or absence of allophanic material.  相似文献   

3.

Purpose

Genetic modification of Bt rice may affect straw decomposition and soil carbon pool under flood conditions. This study aims to assess the effects of cry gene transformation in rice on the residue decomposition and fate of C from residues under flooded conditions.

Materials and methods

A decomposition experiment was set up using 13C-enriched rice straws from transgenic and nontransgenic Bt rice to evaluate the soil C dynamics and CH4 or CO2 emission rates in the root and non-root zones. The concentrations and stable carbon isotope compositions of the soil organic carbon (SOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC), CH4, and CO2 of the root and non-root zones were determined from 7 to 110 days after rice straw incorporation.

Results and discussion

Rice straw incorporation into soil significantly increased the SOC, DOC, and MBC concentrations and the CH4 and CO2 emission rates. The percentage of 13C-SOC remaining in the root zone was significantly lower than that in the non-root zone with rice straw decomposition. The DOC and MBC concentrations significantly increased in both the root and non-root zones between 0 and 80 days after rice straw incorporation. However, no significant differences were found after Bts (Bt rice straw added into soil) and Cks (nontransgenic Bt rice straw added into soil) incorporation in the root and non-root zones. This result may be attributed to the priming effects of sufficient oxygen and nutrients on straw degradation in the root zone.

Conclusions

Bt gene insertion did not affect the SOC, DOC, and MBC concentrations and the CH4 and CO2 emission rates in both the root and non-root zones. However, rice straw incorporation and root exudation significantly increased the SOC, DOC, and MBC concentrations and the CH4 and CO2 emission rates.  相似文献   

4.
小麦和玉米秸秆腐解特点及对土壤中碳、氮含量的影响   总被引：37，自引：4，他引：33  
通过室内模拟培养试验,揭示了不同水分条件下小麦和玉米秸秆在土壤中的腐解特点及对土壤碳、氮含量的影响。结果表明,1)水分条件对有机物质腐解的影响较大,在32 d的培养期间,相对含水量为60%(M60)时,土壤CO2释放速率始终低于含水量80%(M80)的处理。M60条件下释放的CO2-C量占秸秆腐解过程中释放碳总量的40.1%,而M80条件下达到51.5%;M60条件下,添加秸秆土壤中有机碳含量平均提高2.24 g/kg,显著高于M80条件下的1.43 g/kg。2)添加玉米秸秆的土壤,在培养期内CO2释放速率始终高于小麦秸秆处理,CO2-C累积释放量和有机碳净增量分别为408.35 mg/pot和2.12 g/kg;而小麦秸秆处理分别仅为378.94 mg/pot和1.56 g/kg,两种秸秆混合的处理介于二者之间。3)与未添加秸秆相比,土壤中添加小麦或玉米秸秆后,土壤有机碳、微生物量碳、全氮和微生物量氮含量均显著提高,且数量上总体趋势表现为:玉米秸秆两种秸秆混合小麦秸秆。可见,适宜水分条件有利于秸秆腐解过程中秸秆中碳向无机碳方向转化,而不利于向土壤有机碳方向转化;且玉米秸秆比小麦秸秆更易腐解。秸秆在土壤中腐解对补充土壤碳、氮作用很大,可改善土壤微生物生存条件,提高土壤质量。  相似文献   

5.
秸秆及其生物炭对土壤碳库管理指数及有机碳矿化的影响   总被引：6，自引：0，他引：6  
以河南省粮食主产区壤质潮土和砂土为研究对象,通过盆栽试验和室内恒温培养试验,研究了生物炭与不同腐殖化程度的传统有机物料(秸秆和腐熟鸡粪)单施及配施对壤质潮土和砂土有机碳储量、活性及碳库管理指数的影响,并进一步比较了小麦秸秆直接还田和制炭还田对土壤有机碳矿化的影响,以及生物炭对土壤原有有机碳矿化的调控作用。结果表明:相同添加量下,生物炭对土壤有机碳含量的提升效果优于秸秆和腐熟鸡粪,在壤质潮土和砂土上分别较对照提升了63.15%和115.62%。另外,生物炭显著增加了土壤稳态碳含量和土壤碳库指数(CPI),但降低了土壤碳素有效率(SC)和碳库活度指数(AI),对土壤易氧化有机碳(POXC)和碳库管理指数(CMPI)无显著影响,添加秸秆显著增加了2种土壤POXC含量、基础呼吸和CPMI。进一步通过室内恒温培养试验发现,秸秆可在培养前期(0～37天)大幅度提升2种类型土壤有机碳矿化速率和累积矿化量,秸秆制炭还田对土壤有机碳矿化无显著影响。此外生物炭对土壤原有有机碳矿化的调控作用受其施用量、外源活性有机碳输入和土壤类型的影响,高量生物炭(2%)对非秸秆还田土壤有机碳矿化表现出较强的负激发效应,而低量生物炭(0.55%)对秸秆还田土壤有机碳矿化表现出较明显的负激发效应。因此,从"固碳减排"角度考虑,秸秆制炭还田是更合理的利用方式,且应根据土壤施肥管理措施和土壤类型考虑生物炭的施用量,添加质量比为2%的生物炭可显著抑制土壤原有有机碳矿化,降低CO_2排放,但应避开秸秆快速腐解期施用。  相似文献   

6.
An incubation experiment was carried out with maize (Zea mays L.) leaf straw to analyze the effects of mixing the residues with soil and N amendment on the decomposition process. In order to distinguish between soil effects and nitrogen effects for both the phyllospheric microorganisms already present on the surface of maize straw and soil microorganisms the N amendment was applied in two different placements: directly to the straw or to the soil. The experiment was performed in dynamic, automated microcosms for 22 days at 15 °C with 7 treatments: (1) untreated soil, (2) non-amended maize leaf straw without soil, (3) N amended maize leaf straw without soil, (4) soil mixed with maize leaf straw, (5) N amended soil, (6) N amended soil mixed with maize leaf straw, and (7) soil mixed with N amended maize leaf straw. 15NH415NO3 (5 at%) was added. Gas emissions (CO2, 13CO2 and N2O) were continuously recorded throughout the experiment. Microbial biomass C, biomass N, ergosterol, δ13C of soil organic C and of microbial biomass C as well as 15N in soil total N, mineral N and microbial biomass N were determined in soil samples at the end of the incubation. The CO2 evolution rate showed a lag-phase of two days in the non-amended maize leaf straw treatment without soil, which was completely eliminated when mineral N was added. The addition of N generally increased the CO2 evolution rate during the initial stages of maize leaf straw decomposition, but not the cumulative CO2 production. The presence of soil caused roughly a 50% increase in cumulative CO2 production within 22 days in the maize straw treatments due to a slower decrease of CO2 evolution after the initial activity peak. Since there are no limitations of water or N, we suggest that soil provides a microbial community ensuring an effective succession of straw decomposing microorganisms. In the treatments where maize and soil was mixed, 75% of microbial biomass C was derived from maize. We concluded that this high contribution of maize using microbiota indicates a strong influence of organisms of phyllospheric origin to the microbial community in the soil after plant residues enter the soil.  相似文献   

7.
A pot incubation experiment with rice residues (straw and root) was conducted under aerobic condition (60% of WHC, water holding capacity) for a period of 55 days in a greenhouse. The emissions of carbon dioxide (CO2) and nitrous oxide (N2O) were determined by the closed chamber method in a paddy soil. The soil was derived from quaternary red clay, and collected from the Ecological Station of Red Soil, the Chinese Academy of Sciences, located in Jiangxi Province, a subtropical region of China. The emissions of CO2 and N2O were increased by the amendment of rice residues. Significantly positive correlation was found between N2O and CO2 fluxes (R = 0.650*?0.870*, P ≤ 0.05). The cumulative emissions during the early stage of the incubation (<25 days after residue addition) accounted for about 67%–86% and 67%–80% of the total amount of CO2 and N2O emissions, respectively. Cumulative emissions and emission factors of the two gases were higher in the soils amended with rice straw than those with rice root. The two gas fluxes were positively correlated with microbial biomass C and N, as well as soluble organic C. N2O flux was positively correlated with NH4 +–N content at the early stage (<25 days), and negatively with NO3 ?–N content at the later stage of this incubation (25–55 days), implying that both nitrification and denitrification may have contributed to N2O production.  相似文献   

8.
持续棉杆还田对新疆棉田土壤可矿化碳库的影响   总被引：1，自引：0，他引：1  
魏飞  黄金花  马芳霞  景峰  刘建国 《土壤》2017,49(2):295-301
依据新疆绿洲棉花长期连作的微区定位试验,研究了在秸秆还田和不还田处理下,棉田土壤有机碳矿化特征,以及土壤有机碳释放随棉花秸秆还田年限的变化规律.结果表明:秸秆还田与不还田处理相比增加了0~60 cm土层土壤的总有机碳(TOC)、可矿化碳(MC)的含量和矿化速率(MR),并且随着秸秆还田年限的加长呈上升趋势,但随土层的加深而下降.持续秸秆还田后棉田随着秸秆还田时间增加土壤有机碳矿化速率、累积矿化排放量(CO2-C排放量)增加,但矿化强度呈降低趋势,而棉花连作但秸秆不还田的棉田变化趋势与之相反.说明棉花秸秆还田措施增加了新疆绿洲棉田土壤有机碳含量,土壤中有机碳虽然不断得到补充,但尚未达到饱和状态,随着秸秆还田时间延长棉田固碳能力下降.  相似文献   

9.
Summary Soil was amended with a variety of carbon sources, including four soluble compounds (glucose, sucrose, glycerol and mannitol) and two plant residues (straw and alfalfa).. Potential denitrification rates, measured both as N2O accumulation and NO3 – disappearance, were compared, and the predicted values of available C, measured as CO2 production and water-extractable C, were assessed.The two measures of denitrification agreed well although N2O accumulation was, found to be most sensitive. Soil treated with the four soluble C compounds resulted in the same rate of denitrification although glycerol was not as rapidly oxidized. Alfalfa-amended soil produced a significantly higher rate of denitrification than the same amount of added straw. CO2 evolution was found to be a good predictor of denitrification over the first 2 days of sampling, but neither measure of available substrate C correlated well with denitrification rate beyond 4 days, when NO3 – was depleted in most treatments. The data with alfalfa-amended soil suggested that denitrifiers used water-extractable C. materials produced by other organisms under anaerobic conditions.  相似文献   

10.
Five microbial species (Aspergillus flavus, Trichoderma viride, Streptomyces sp., Arthrobacter sp., Achromobacter liquefaciens) were cultivated in liquid media containing 14C-labelled glucose. The decomposition of these microorganisms was recorded in four different soils after chloroform fumigation by a technique related to that proposed by Jenkinson and Powlson, to determine the mineralization rate of microbial organic matter (Kc coefficient). Three treatments were used: untreated soil, fumigated soil alone and fumigated soil supplied with 14C-labelled cells. Total evolved CO2 and 14CO2 were measured after 7 and 14 days at 28°C.The labelled microorganisms enabled the calculation of mineralization rate Kc (Kc = mineralized microbial carbon/supplied microbial carbon). The extent of mineralization of labelled microbial carbon depended on the type of soil and on the microbial species. Statistical analysis of results at 7 days showed that 58% of the variance is taken in account by the soil effect and 32% by the microorganism effect. Between 35 and 49% of the supplied microbial C was mineralized in 7 days according to the soil type and the species of microorganism. Our results confirmed that the average value for Kc = 0.41 is acceptable, but Kc variability according to soil type must be considered.The priming effect on organic C and native microbial biomass mineralization, due to microbial carbon addition was obtained by comparison between the amount of non-labelled CO2-C produced by fumigated soils with or without added labelled microorganisms: this priming effect was generally negligible.These results indicate that the major portion of the error of microbial biomass measurement comes from the Kc estimation.  相似文献   

11.
不同管理措施对滨海盐渍农田土壤CO2排放及碳平衡的影响   总被引：1，自引：0，他引：1  
米迎宾  杨劲松  姚荣江  余世鹏 《土壤》2016,48(3):546-552
为探讨不同管理措施对滨海盐渍农田碳平衡的影响,本文通过玉米–小麦轮作试验,研究农田土壤的CO_2释放规律,及其农田碳收支状况。试验设计6个处理:1常规对照(CK);2有机肥常量(OF);3氮肥增施(NF);4秸秆还田(S);5有机肥加秸秆(OF+S);6免耕(NT)。研究表明,秸秆还田和有机肥的施用增加了土壤呼吸的强度,而免耕处理的CO_2平均释放量最低,不同处理下土壤呼吸总体表现为OF+SSOMNFCKNT。各处理土壤有机碳含量随着作物的收获逐渐升高,其中OF与NT增加最多,而增施氮肥处理并没有显著提高土壤的有机碳水平。各处理间的有机碳含量没有显著性差异。在两季作物种植结束后,各处理的碳输入均高于碳输出,均为碳净输入,表现出较强的碳汇特征。秸秆还田和单施有机肥的碳净输入均显著高于对照,可有效减缓因农田土壤CO_2排放而造成的全球气候变化问题。  相似文献   

12.
Summary A study was conducted to determine the effects of grinding, added N, and the absence of soil on C mineralization from agricultural plant residues with a high C:N ratio. The evolution of CO2 from ground and unground wheat straw, lentil straw, and lentil green manure, with C:N ratios of 80, 36, and 9, respectively, was determined over a period of 98 days. Treatments with added N were included with the wheat and lentil straw. Although the CO2 evolution was initially much faster from the lentil green manure than from the lentil or wheat straw, by 98 days similar amounts of CO2 had evolved from all residues incubated in soil with no added N. Incubation of plant residues in the absence of soil had little effect on CO2 evolution from the lentil green manure or lentil straw but strongly reduced CO2 evolution from the wheat straw. Grinding did not affect CO2 evolution from the lentil green manure but increased CO2 evolution from the lentil straw with no added N and from the wheat straw. The addition of N increased the rate of CO2 evolution from ground wheat straw between days 4 and 14 but not from unground wheat straw, and only slightly increased the rate of CO2 evolution from lentil straw during the initial decomposition. Over 98 days, the added N reduced the amounts of CO2 evolved from both lentil and wheat straw, due to reduced rates of CO2 evolution after ca. 17 days. The lack of an N response during the early stages of decomposition may be attributed to the low C:N ratio of the soluble straw component and to microbial adaptations to an N deficiency, while the inhibitory effect of N on CO2 evolution during the later stages of decomposition may be attributed to effects of high mineral N concentrations on lignocellulolytic microorganisms and enzymes.  相似文献   

13.
李力  陈明茹  张久红  张军  黄应平  袁喜  李萌 《土壤》2022,54(5):1058-1063
本文通过土壤腐解试验研究外源添加水稻或玉米秸秆对多环芳烃（PAHs）污染土壤CO2-C释放和污染物去除率的影响，同时清晰秸秆腐解中间产物溶解性有机碳（DOC）与土壤PAHs降解的关系。结果表明：秸秆添加处理促进了PAHs污染土壤CO2-C的释放，以玉米秸秆提升效果较好。外源添加秸秆显著增加了土壤DOC含量，且增加幅度随秸秆添加量的增加而增大；水稻秸秆对土壤DOC含量的提升幅度较大。与对照相比，秸秆添加处理下土壤菲、芘残留量均显著降低，菲、芘去除率显著增加，去除效果：玉米＞水稻，高量＞低量，菲＞芘；与对照相比，添加高量玉米秸秆处理（PY15）对土壤菲、芘去除率的增加幅度分别为91.7%和182%。此外，在一定范围内土壤DOC含量与PAHs去除率呈正相关关系。可见，农作物秸秆，尤其是玉米秸秆添加可提升PAHs污染土壤有机碳矿化，亦可在提升土壤DOC含量的同时促进污染土壤PAHs的降解。  相似文献   

14.
[目的]降低烤烟生长后期植烟土壤的氮素供应对提高烤烟烟叶质量非常重要,而微生物同化作用在调控土壤有效氮含量过程中起着重要作用,且受添加有机碳源质量和数量的影响.因此,我们研究不同有机碳源降低土壤矿质氮的效果,以及碳添加量与矿质氮降低量间的定量关系.[方法]供试土壤采自贵州玉米烟草轮作土壤,属于黄壤土.供试有机碳源有5种...  相似文献   

15.
Agricultural peat soils in the Sacramento-San Joaquin Delta, California have been identified as an important source of dissolved organic carbon (DOC) and trihalomethane precursors in waters exported for drinking. The objectives of this study were to examine the primary sources of DOC from soil profiles (surface vs. subsurface), factors (temperature, soil water content and wet-dry cycles) controlling DOC production, and the relationship between C mineralization and DOC concentration in cultivated peat soils. Surface and subsurface peat soils were incubated for 60 d under a range of temperature (10, 20, and 30 °C) and soil water contents (0.3-10.0 g-water g-soil−1). Both CO2-C and DOC were monitored during the incubation period. Results showed that significant amount of DOC was produced only in the surface soil under constantly flooded conditions or flooding/non-flooding cycles. The DOC production was independent of temperature and soil water content under non-flooded condition, although CO2 evolution was highly correlated with these parameters. Aromatic carbon and hydrophobic acid contents in surface DOC were increased with wetter incubation treatments. In addition, positive linear correlations (r2=0.87) between CO2-C mineralization rate and DOC concentration were observed in the surface soil, but negative linear correlations (r2=0.70) were observed in the subsurface soil. Results imply that mineralization of soil organic carbon by microbes prevailed in the subsurface soil. A conceptual model using a kinetic approach is proposed to describe the relationships between CO2-C mineralization rate and DOC concentration in these soils.  相似文献   

16.
Rice residue management often leads to increased methane (CH4) emissions but the outcomes of edaphic and management factors are not always predictable. Rice residue can act as a substrate for CH4 production; however the role it plays in priming (mineralization) of soil organic matter (SOM) to release additional substrates for CH4 production are not well established. We anaerobically incubated a highly organic soil with 13C-enriched rice straw for 3 months to investigate its priming effect (PE) on SOM and source of C for CH4 production. Anaerobic decomposition of SOM was accompanied by iron (Fe) reduction with minimal CH4 production when straw was absent. Straw addition enhanced Fe reduction and increased CH4 production concurrently with a clear succession of microbial community structure and function assessed with phospholipid fatty acid (PLFA) profiling. The PE on CH4 production from SOM was strong and positive during the entire experiment. Overall, PE on SOM (CO2 plus CH4 production) was slightly positive at the end of the experiment, associated with only a 32% mineralization of the added straw-C (as CO2 plus CH4). Straw addition also released large amounts of dissolved organic carbon (DOC) from SOM. Our results suggest that straw addition effects on PE of SOM and CH4 production can last for a long period of time showing that straw will cause non-linear response in CH4 production and potentially result in significant losses of soil C as DOC by leaching or direct exports in histosols.  相似文献   

17.
《Soil biology & biochemistry》2001,33(4-5):583-591
Short-term effects of actively burrowing Octolasion lacteum (Örl.) (Lumbricidae) on the microbial C and N turnover in an arable soil with a high clay content were studied in a microcosm experiment throughout a 16 day incubation. Treatments with or without amendment of winter wheat straw were compared under conditions of a moistening period after summer drought. The use of 14C labeled straw allowed for analyzing the microbial use of different C components. Microbial biomass C, biomass N and ergosterol were only slightly affected by rewetting and not by O. lacteum in both cases. Increased values of soil microbial biomass were determined in the straw treatments even after 24 h of incubation. This extra biomass corresponded to the initial microbial colonization of the added straw. O. lacteum significantly increased CO2 production from soil organic matter and from the 14C-labeled straw. Higher release rates of 14C-CO2 were recorded shortly after insertion of earthworms. This effect remained until the end of the experiment. O. lacteum enhanced N mineralization. Earthworms significantly increased both mineral N content of soil and N leaching in the treatments without straw addition. Moreover, earthworms slightly reduced N immobilization in the treatments with straw addition. The immediate increase in microbial activity suggests that perturbation of soil is more important than substrate consumption for the effect of earthworms on C and N turnover in moistening periods after drought.  相似文献   

18.
The effect of soil aeration status on carbon partitioning of a labelled organic substrate (14C-[U]-glucose) into CO2, microbial biomass, and extra-cellular metabolites is described. The soil was incubated in a continuous flow incubation apparatus under four different aeration conditions: (1) permanently aerobic, (2) permanently anaerobic, (3) shifted from anaerobic to aerobic, and (4) shifted from aerobic to anaerobic. The soil was pre-incubated for 10 days either under aerobic or under anaerobic conditions. Afterwards, glucose was added (315 g C g–1) and the soils were incubated for 72 h according to four treatments: aerobic or anaerobic conditions maintained, aerobic conditions shifted to anaerobic conditions and anaerobic conditions shifted to aerobic conditions. Carbon partitioning was measured 0, 8, 16, 24, 48 and 72 h after the glucose addition. In permanently aerobic conditions, the largest part of the consumed glucose was built into microbial biomass (72%), much less was mineralised to CO2 (27%), and only a negligible portion was transformed to soluble extra-cellular metabolites. Microbial metabolism was strongly inhibited when aeration conditions were changed from aerobic to anaerobic, with only about 35% of the added glucose consumed during the incubation. The consumed glucose was transformed proportionally to microbial biomass and CO2. In permanently anaerobic conditions, 42% of the consumed glucose was transformed into microbial biomass, 30% to CO2, and 28% to extra-cellular metabolites. After a shift of anaerobic to aerobic conditions, microbial metabolism was not suppressed and the consumed glucose was transformed mainly to microbial biomass (75%) and CO2 (23%). Concomitant mineralisation of soil organic carbon was always lower in anaerobic than in aerobic conditions.  相似文献   

19.
The influence of Cd on the decomposition of various types of organic materials in soil was studied. CdCl2 or CaCl2 (control) was added to a Gley soil at a level of 10 mmol kg-1 soil. Three days later, organic materials including glutamic acid, glucose, casein, starch, cellulose, lignin, rice straw, rice straw compost, or 3 kinds of sludges were mixed with the soil in a proportion of 1%, respectively. During an 8-week period of incubation at 28°C, CO2 evolution was measured periodically. At the end of the incubation period, the form of Cd in the soil was analyzed by successive extractions with water, CaCl2, CH3COOH, Na4P2O7, and with hot HCl after HNO3-HClO4 digestion.

The decomposition of all the organic materials was inhibited by the addition of Cd, but the degree of inhibition varied considerably among the types of organic materials. The decomposition of rice straw, rice straw compost, and sludges was markedly inhibited by Cd. The amount of water-soluble Cd was less in the soils treated with rice straw, rice straw compost, and sludges than in the soils treated with other types of organic materials, while the amounts of CaCI2-extractable Cd were much larger in the latter soils. In the case of rice straw, rice straw compost, and sludges Cd was easily adsorbed from the CdCl2 solution.

These results suggest that the inhibition of organic matter decomposition by Cd is caused by the adsorption of Cd onto organic matter.  相似文献   

20.
A short-term incubation study was carried out to investigate the effect of biochar addition to soil on CO2 emissions, microbial biomass, soil soluble carbon (C) nitrogen (N) and nitrate–nitrogen (NO3–N). Four soil treatments were investigated: soil only (control); soil + 5% biochar; soil + 0.5% wheat straw; soil + 5% biochar + 0.5% wheat straw. The biochar used was obtained from hardwood by pyrolysis at 500 °C. Periodic measurements of soil respiration, microbial biomass, soluble organic C, N and NO3–N were performed throughout the experiment (84 days). Only 2.8% of the added biochar C was respired, whereas 56% of the added wheat straw C was decomposed. Total net CO2 emitted by soil respiration suggested that wheat straw had no priming effect on biochar C decomposition. Moreover, wheat straw significantly increased microbial C and N and at the same time decreased soluble organic N. On the other hand, biochar did not influence microbial biomass nor soluble organic N. Thus it is possible to conclude that biochar was a very stable C source and could be an efficient, long-term strategy to sequester C in soils. Moreover, the addition of crop residues together with biochar could actively reduce the soil N leaching potential by means of N immobilization.  相似文献   

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