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1.
人工林代替天然林后土壤碳库的变化   总被引：19，自引：8，他引：19  
Changes in soil carbon pools under Chinese fir (Cunninghamia lanceolata) and bamboo (Phyllostachys pubescent) plantations substituted for a native forest (Quercus acutissima, Cyclobalanopsis glauca, Cas-tanops~.s sclerophyUa, Platycarya strobilacea, Lithocarpus glaber) were studied on the hills with acid parent rock and soils classified as red soils (Ferrisols) in Huzhou, Zhejiang Province of east China. It was found that total soil organic carbon (TSOC), easily oxidisable carbon (EOC) and water-soluble organic carbon(WSOC) under bamboo plantation were increased, but microbial biomass carbon (MBC) was decreased. On the contrary, Chinese fir induced declines of all fractions of C including TSOC, EOC, WSOC and MBC.The percentages of the active fractions of soil C (EOC and WSOC) were increased in the plantations as compared to the native broad-leaved forest, but proportions of soil organic C as MBC were decreased. It could be concluded that bamboo plantation had a great ability of not only fixing C but also accelerating soil C pool cycle, improving nutrient and microorganism activity; therefore, it is a good ecosystem and could be recommended for wide development. Chinese fir would shrink the soil C pool and deteriorate sou biological fertility, so it did not benefit CO2 fixing and land sustainable utilization.  相似文献   

2.
不同森林植被下土壤活性有机碳的含量及动态变化   总被引：11，自引：0，他引：11  
Soil organic matter （SOM） in forest ecosystems is not only important to global carbon （C） storage but also to sustainable management of forestland with vegetation types, being a critical factor in controlling the quantity and dynamics of SOM. In this field experiment soil plots with three replicates were selected from three forest vegetation types： broadleaf, Masson pine （Pinus massoniana Lamb.）, and Chinese fir （Cunninghamia lanceolata Hook.）. Soil total organic C （TOC）, two easily oxidizable C levels （EOC1 and EOC2, which were oxidized by 66.7 mmol L^-1 K2Cr2O7 at 130-140℃ and 333 mmol L^-1 KMnO4 at 25 ℃, respectively）, microbial biomass C （MBC）, and water-soluble organic C （WSOC） were analyzed for soil samples. Soil under the broadleaf forest stored significantly higher TOC （P ≤ 0.05）. Because of its significantly larger total soil C storage, the soil under the broadleaf forest usually had significantly higher levels （P ≤ 0.05） of the different labile organic carbons, EOC1, EOC2, MBC, and WSOC; but when calculated as a percentage of TOC each labile C fraction of the broadleaf forest was significantly lower （P ≤ 0.05） than one of the other two forests. Under all the three vegetation types temperature as well as quality and season of litter input generally affected the dynamics of different organic C fractions in soils, with EOC1, EOC2, and MBC increasing closely following increase in temperature, whereas WSOC showed an opposite trend.  相似文献   

3.
不同橡胶生长期土壤中的微生物生物量碳和有机碳   总被引：16，自引：6，他引：16  
ZHANG Hu  ZHANG Gan-Lin 《土壤圈》2003,13(4):353-357
Soil samples were collected from different rubber fields in twenty-five plots selected randomly in the Experimental Farm of the Chinese Academy of Tropical Agriculture Sciences located in Hainan, China, to analyse the ecological effect of rubber cultivation. The results showed that in the tropical rubber farm, soil microbial biomass C (MBC) and total organic C (TOC) were relatively low in the content but highly correlated with each other. After rubber tapping, soil MBC of mature rubber fields decreased significantly, by 55.5%, compared with immature rubber fields. Soil TOC also decreased but the difference was not significant. Ratios of MBC to TOC decreased significantly. The decreasing trend of MBC stopped at about ten years of rubber cultivation. After this period, soil MBC increased relatively while soil TOC still kept in decreasing. Soil MBC changes could be measured to predict the tendency of soil organic matter changes due to management practices in a tropical rubber farm several years before the changes in soil TOC become detectable.  相似文献   

4.
Phyllostachys praecox C. D. Chu et C. S. Chao, a favored bamboo shoot species, has been widely planted in recent years. Four stands with different historical management practices were selected for this study to understand the evolution of soil microbial ecology by determining the effects of a new mulching and heavy fertilization practice on soil quality using microbiological parameters. Compared with the traditional practice (index 1), microbial biomass carbon (MBC) and soil microbial respiration carbon (MRC) with the new management practice significantly decreased (P < 0.01 and P < 0.05, respectively) with 1--2 years of mulching (index 2) and then for continued mulching significantly increased (P < 0.05). The ratios of MBC/TOC (total organic carbon) and MRC/TOC also significantly diminished (P < 0.05) with mulching. The average well color development (AWCD) and Shannon index decreased with mulching time, and the significant decrease (P < 0.05) in Shannon index occurred from index 2 to index 3. The results from a principal components analysis (PCA) showed that the scores of the first principal component for indexes 1 and 2 were significantly larger (P < 0.05) than soils mulched 3--4 years or 5--6 years. Also, the second principal component scores for index 1 were larger than those for index 2, suggesting that the ability of soil microorganisms to utilize soil carbon was decreasing with longer use of the new management practice and causing a deterioration of soil biological properties.  相似文献   

5.
In the Three Gorges Area of China, soil erosion and the resultant non-point source pollution and ecological degradation have endangered agricultural ecosystems and fresh water reservoirs. Although efforts have been undertaken to reduce soil and water losses from slope land used for citrus production, information on the effects of management practices on soil fertility indices is either limited or nonexistent. This study was conducted to compare the effects of 10 years of various management practices, citrus intercropped with white clover (WC), citrus mulched with straw (SM), citrus intercropped with contour hedgerows (CH), citrus orchard land with impermeable membrane (IM), and citrus intercropped with wheat (Triticum aestivum) and peanut (Arachris hypogaea) (WP), as treatments on soil fertility indices with that of the conventional citrus management (CM). Results showed that the soil organic carbon, total and available nitrogen, available potassium, and water-stable aggregate (> 0.25 mm) contents at the 0–5 cm depth were higher for the WC and SM treatments than the CM treatment. There was also spatial variation in soil fertility along slopes of the WC and SM treatments. The soil total and available nitrogen, phosphorus, and potassium, and water-stable aggregate (> 0.25 mm) contents at both the 0–5 and 5–20 cm depths were higher for the CH and IM treatments than the CM treatment. The average soil available nitrogen and available potassium contents were higher for the WP treatment than the CM treatment, but the WP treatment had little effect on the soil organic carbon, total nitrogen, and water-stable aggregate (> 0.25 mm) contents. These suggested that white clover intercropping and straw mulching were the most effective approaches to improve soil fertility in citrus orchard land of the Three Gorges area.  相似文献   

6.
Soil total organic carbon (TOC) is a composite indicator of soil quality with implications for crop production and the regulation of soil ecosystem services. Research reports on the dynamics of TOC as a consequence of soil management practices in subtropical climatic conditions, where microbial carbon(C) loss is high, are very limited. The objective of our study was to evaluate the impact of seven years of continuous tillage and residue management on soil TOC dynamics (quantitative and qualitati...  相似文献   

7.
Based on data from 10-year field experiments on residue/fertilizer management in the dryland farming region of northern China, Century model was used to simulate the site-specific ecosystem dynamics through adjustment of the model＇s parameters, and the applicability of the model to propose soil organic carbon （SOC） management temporally and spatially, in cases such as of tillage/residue/fertilization management options, was identified v/a scenario analysis.Results between simulations and actual measurements were in close agreement when appropriate applications of stover,manure and inorganic fertilizer were combined. Simulations of extreme C/N ratios with added organic materials tended to underestimate the measured effects. Scenarios of changed tillage methods, residue practices and fertilization options showed potential to maintain and enhance SOC in the long run, while increasing inorganic N slowed down the SOC turnover rate but did not create a net C sink without any organic C input. The Century model simulation showed a good relationship between annual C inputs to the soil and the rate of C sequestration in the top 20 cm layer and provided quantitative estimations of changes in parameters crucial for sustainable land use and management. Conservation tillage practices for sustainable land use should be integrated with residue management and appreciable organic and inorganic fertilizer application, adapted according to the local residue resource, soil fertility and production conditions. At least 50% residue return into the soil was needed annually for maintenance of SOC balance, and manure amendment was important for enhancement of SOC in small crop-livestock systems in which crop residue land application was limited.  相似文献   

8.
LIAO Min  XIE Xiao-Mei 《土壤圈》2007,17(1):101-108
The distribution of light fraction carbon （LF-C） in the various size classes of aggregates and its relationship to water- stable aggregates as well as the influence of cultivation on the organic components in virgin and cultivated black soils were studied by wet sieving and density separation methods. The total organic carbon （TOC） and LF-C were significantly higher （P≤ 0.05） in the virgin soils than in the cultivated soils. The LF-C in aggregates of different size classes varied from 0.9 to 2.5 g kg^-1 in the cultivated soils and from 2.5 to 7.1 g kg^-1 in the virgin soils, whereas the ratio of LF-C to TOC varied from 1.9% to 7.3% and from 5.0% to 12.2%, respectively. After being incubated under constant temperature and controlled humidity for three months, the contribution of LF-C to TOC sharply decreased to an amount （1.7%4.5%） close to the level in soils that had been cultivated for 20 to 25 years （1.3%-8.8%）. As a result, the larger water-stable macro-aggregates （especially 〉 1 mm） decreased sharply, indicating that the LF-C pool in virgin soils declined quickly after cultivation, which reduced the water stability of soil aggregates.  相似文献   

9.
城郊土壤不透水表面有土壤机碳转化及其相关性质的研究   总被引：2，自引：0，他引：2  
Installation of impervious surface in urban area prevents the exchange of material and energy between soil and other environmental counterparts, thereby resulting in negative effects on soil function and urban environment. Soil samples were collected at 0-20 cm depth in Nanjing City, China, in which seven sites were selected for urban open soils, and fourteen sites with similar parent material were selected for the impervious-covered soils, to examine the effect of impervious surface on soil properties and microbial activities, and to determine the most important soil properties associated with soil organic carbon （SOC） transformation in the urban soils covered by impervious surfaces. Soil organic carbon and water-soluble organic carbon （WSOC） concentrations, potential carbon （C） and nitrogen （N） mineralization rates, basal respiration, and physicochemical properties with respect to C transformation were measured. Installation of impervious surface severely affected soil physicochemical properties and microbial activities, e.g., it significantly decreased total N contents, potential C mineralization and basal respiration rate （P 〈 0.01）, while increased pH, clay and Olsen-P concentrations. Soil organic carbon in the sealed soils at 0-20 cm was 2.35 kg m-2, which was significantly lower than the value of 4.52 kg m-2 in the open soils （P 〈 0.05）. Canonical correlation analysis showed WSOC played a major role in determining SOC transformation in the impervious-covered soil, and it was highly correlated with total N content and potential C mineralization rate. These findings demonstrate that installation of impervious surface in urban area, which will result in decreases of SOC and total N concentrations and soil microbial activities, has certain negative consequences for soil fertility and long-term storage of SOC.  相似文献   

10.
Labile soil organic carbon(SOC) pools, estimated through chemical fractionation techniques, are considered sensitive indicators of management-induced changes in quality and composition of soil organic matter. Although the impacts of organic manure and crop residue applications on C sequestration in rice-wheat system are fairly well documented, their influence on labile SOC pools is relatively less known. Impacts of organic manure, rice straw, and inorganic fertilizer nitrogen(N) applications on soil total organic carbon(TOC)and SOC pools including water-extractable organic C(WEOC), hot water-soluble organic C(HWOC), potassium permanganateoxidizable organic C(KMnO 4-C), microbial biomass C(MBC), mineralizable organic C(Cmin), and the oxidizable fractions of decreasing oxidizability(easily-oxidizable, oxidizable, and weakly-oxidizable) were investigated in an 11-year field experiment under rice-wheat system. The field experiment included treatments of different combinations of farmyard manure, rice straw, and fertilizer N application rates, with C inputs estimated to be in the range from 23 to 127 Mg ha-1. After 11 years of experiment, WEOC,HWOC, and KMnO 4-C were 0.32%–0.50%, 2.2%–3.3%, and 15.0%–20.6% of TOC, respectively. The easily-oxidizable, oxidizable,and weakly-oxidizable fractions were 43%–57%, 22%–27%, and 10%–19% of TOC, respectively. The applications of farmyard manure and rice straw improved WEOC, HWOC, KMnO 4-C, easily-oxidizable fraction, Cmin, and MBC, though the rates of change varied considerably from-14% to 145% and-11% to 83% of TOC, respectively. At the C input levels between 29 and 78 Mg C ha-1during the 11-year period, the greatest increase was observed in WEOC and the minimum in KMnO 4-C. Water-extractable organic C exhibited a relatively greater sensitivity to management than TOC, suggesting that it may be used as a sensitive indicator of management-induced changes in soil organic matter under rice-wheat system. All the other labile SOC pools exhibited almost the same sensitivity to management as TOC. Most of the SOC pools investigated were positively correlated to each other though their amounts differed considerably. Long-term applications of farmyard manure and rice straw resulted in build-up of not only the labile but also the recalcitrant pool of SOC, emphasizing the need for continued application of organic amendments for permanence of the accrued C under the experimental conditions.  相似文献   

11.
集约经营毛竹林土壤活性有机碳库研究   总被引：38，自引：7，他引：38  
为了解毛竹林集约经营后土壤有机碳库发生的变化,采集了集约经营历史5～10年竹林的土壤样品进行分析,并与粗放经营毛竹林进行比较。研究结果表明:毛竹林集约经营后土壤总有机碳、水溶性有机碳和微生物量碳含量都明显减少,与粗放经营毛竹林之间有显著差异(P<0.05),并且微生物量碳占总有机碳比例也显著降低,水溶性有机物质的分子量也明显变小。集约经营后竹林土壤矿化态碳数量及其占总有机碳比例增强,说明毛竹集约经营使土壤有机物质稳定性变差,矿化率增加。毛竹林土壤总有机碳、水溶性碳、微生物量碳及矿化态碳两两之间相关性均达极显著水平(P<0.01),土壤各类有机碳含量与土壤全氮、水解氮含量间相关性也达显著或极显著水平。毛竹集约经营未改变各类有机碳的剖面变化特征。  相似文献   

12.
以起始于1984年的长期不同经营模式毛竹林为研究对象,探讨了夏季毛竹林集约经营后土壤有机碳的变化。结果表明:(1)集约经营后0~80 cm土层毛竹林土壤总有机碳平均增加了5.48%,易氧化碳含量平均增加了15.14%,水溶性有机碳含量平均下降了3.98%,三者均未达到显著差异。(2)两种毛竹林土壤总有机碳、易氧化碳、水溶性有机碳的剖面特征均随土层深度的增加而呈现下降趋势,但下降速度不同。集约经营在一定程度上影响毛竹土壤易氧化碳剖面特征。(3)土壤总有机碳、易氧化碳与土壤养分之间相关性均达到极显著水平,而水溶性有机碳与土壤养分之间相关性不显著。(4)集约经营提高了土壤易氧化碳占总有机碳的比例、土壤碳库活度,并在土壤剖面部分土层差异达到显著水平。但其水溶性有机碳占总有机碳的比例3.74%,低于粗放经营毛竹林的4.10%。因此,集约经营的毛竹林,通过配施恰当比例的有机无机肥,结合土壤垦复、除草、合理的竹株留养和采伐等综合竹林经营技术,以达到改善土壤质量和实现毛竹林可持续经营的目的,也可改善土壤生物化学活性。  相似文献   

13.
土壤碳库管理指数（CPMI）可以比较准确地发现人为因素对土地利用的干扰情况。以伊犁河谷不同土地利用类型（耕地、林地、草地和荒地）为研究对象,分析了不同土地利用类型土壤有机碳（SOC）含量、活性有机碳含量及其在SOC中的分配情况,各类有机碳含量之间的相关性、CPMI。研究表明:（1）不同土地利用类型SOC含量和水溶性有机碳（WSOC）含量有显著差异,SOC含量为草地 > 林地 > 耕地 > 荒地;WSOC含量为耕地（最高） > 荒地（最低）;易氧化碳（ROC）含量为草地最低;在0—20 cm和20—40 cm土层,微生物量碳（MBC）含量为草地（最高） > 林地（最低）;ROC含量为荒地高于草地。不同土地利用类型SOC含量均随土层深度增加而降低;ROC含量均随土层深度增加而升高;除林地外,其他样地MBC含量均随土层深度增加呈先升高后降低趋势,而WSOC含量均随土层深度增加而逐渐降低。（2）不同土地利用类型下ROC,MBC和WSOC所占SOC比例各不相同,且碳库的活度主要取决于ROC所占比例,ROC所占比例为荒地 > 耕地 > 林地 > 草地;MBC所占比例为荒地 > 耕地 > 草地 > 林地;WSOC所占比例为耕地 > 林地 > 荒地 > 草地。同一土地利用类型各活性有机碳所占比例情况为ROC > MBC > WSOC。（3）不考虑土层深度影响,耕地ROC含量与MBC含量呈极显著线性负相关;林地SOC含量与ROC含量呈显著线性负相关;荒地SOC含量与WSOC含量呈极显著线性正相关。不同土地利用类型下SOC,ROC,MBC,WSOC含量之间线性相关程度总体偏低。（4）同一土地利用类型,CPMI均随土层深度的加深先增大后减小;0—20 cm土层的CPMI为林地 > 荒地（100） > 耕地 > 草地。土地利用类型由荒地、草地、耕地转变为林地,有利于CPMI的提高,有利于土壤培肥,促进碳循环。  相似文献   

14.
毛竹林土壤有机碳及微生物量碳特征研究   总被引：7，自引：0，他引：7  
通过对湖南会同林区集约经营毛竹林地土壤有机碳和微生物量碳进行测定,结果表明,毛竹林地土壤(0-60 cm)有机碳和微生物量碳含量平均值分别为1.727%和551.84 mg/kg,不同土壤层次有机碳和微生物量碳含量差异极显著,其中,0-20 cm土层有机碳含量平均值为2.607%,分别是20-40 cm和40-60 cm土层有机碳含量的1.67倍和2.57倍;0-20 cm土层的微生物量碳占土壤总微生物量碳的58.9%,分别是20-40 cm和40-60 cm土层的2.69倍和3.08倍。不同季节间土壤微生物量碳有明显变化规律,即土壤微生物量碳含量1-7月份呈上升的趋势,7月达到最大值,8-12月份呈逐渐下降趋势;不同季节间有机碳含量差异不显著。毛竹林地土壤表层土壤微生物量熵为1.118 6%,与40-60 cm土壤层相当,略高于20-40 cm土壤层,说明毛竹林不同土壤层次有机碳积累强度相当。  相似文献   

15.
Impact of combined application of inorganic and organic fertilizers on soil carbon dioxide (CO2) emission is poorly understood. We investigated the effects of inorganic fertilizer (IF), organic fertilizer (OF), and a mixture of organic and inorganic fertilizers (OIF) applications on the dynamics of soil CO2 efflux in intensively managed Moso bamboo plantations. Soil CO2 efflux and concentrations of water soluble organic C (WSOC) and microbial biomass C (MBC) in the IF treatment were higher than those in the control but lower than those in the OF and OIF treatments. Both OF and OIF treatments increased the SOC stock. Strong exponential relationships (p < 0.01) between soil temperature and CO2 efflux were observed in all treatments. Soil CO2 efflux in all four treatments was correlated with WSOC (p < 0.05) but not with MBC. We concluded the combined approach can possibly contribute to increasing the level of SOC stock in intensively managed plantations.  相似文献   

16.
长期施肥下黑土活性有机碳变化特征   总被引：5，自引：1，他引：4  
观测分析了黑土长期不同施肥30年后不同形态的活性有机碳含量(易氧化有机碳>轻组有机碳>微生物量碳>水溶性有机碳)的变化特征。结果表明,长期施用氮、氮磷和氮磷钾化肥对土壤活性有机碳无显著影响;长期施用有机肥以及有机肥配施化肥均显著提高了土壤活性有机碳含量,与不施有机肥相比,有机肥区组中土壤轻组有机碳和水溶性有机碳含量增幅较大,分别在122%～258%和237%～351%之间,而土壤易氧化有机碳和微生物量碳含量增幅分别在72%～98%和83%～112%。黑土不同形态活性有机碳对施肥的响应灵敏度为,轻组有机碳>水溶性有机碳>微生物量碳≈易氧化有机碳。因此,轻组有机碳是指示土壤有机碳变化的较好指标。  相似文献   

17.
张宇婕  于亚军 《土壤》2019,51(4):732-738
土壤有机碳含量是土壤肥力状况的重要标志之一,其活性组分对田间管理措施反映敏感。因此,分析煤矸山复垦重构土壤有机碳含量及其组分差异对于揭示土壤碳库变化、指导复垦地田间管理措施的实施有重要意义。本研究以山西省霍州曹村煤矸山复垦后5a(R-5a)、7a(R-7a)和9a(R-9a)的果园为对象,通过与当地原地貌果园(CK)对比,分析了3种复垦样地土壤总有机碳(TOC)及其组分可溶性有机碳(DOC)、微生物生物量碳(MBC)、轻组有机碳(LFOC)和重组有机碳(HFOC)的差异,以及与土壤环境因子间的关系。结果表明:①随复垦年限的增加,3种复垦样地土壤TOC、LFOC和HFOC含量均呈先增后减趋势,DOC含量呈增加趋势,MBC含量呈先减后增趋势;但与CK相比,3种复垦样地土壤TOC、DOC、MBC、LFOC和HFOC含量均明显偏低。②DOC/TOC和MBC/TOC在R-7a样地中最低,LFOC/TOC随复垦年限的增加呈增加趋势,HFOC/TOC呈减少趋势,表明土壤中更多的有机碳从稳定态转变为活性态。③土壤全氮、全磷、碱解氮、碳氮比、黏粒含量、pH和含水量均不同程度影响有机碳含量,其中全氮、全磷、黏粒含量和土壤pH为关键因子。  相似文献   

18.
竹叶及其生物质炭输入对板栗林土壤N2O通量的影响   总被引：2，自引：1，他引：1  
【目的】氧化亚氮(N2O)是温室气体的主要组成部分,其增温效应极强,陆地生态系统是N2O的主要排放源之一。人工林生态系统是陆地生态系统的重要组成部分,但目前关于经营措施对人工林生态系统土壤N2O通量的影响研究较少。本文研究了竹叶及其生物质炭输入对板栗林土壤N2O排放通量的影响,为调控亚热带人工林土壤N2O排放通量提供理论基础与科学依据。【方法】定位试验于2012年7月~2013年7月在浙江省临安市三口镇典型板栗林区进行,设对照、输入竹叶、输入生物质炭3个处理,利用静态箱-气相色谱法测定板栗林土壤N2O通量的动态变化以及土壤温度、土壤含水量、水溶性有机碳(WSOC)、水溶性有机氮(WSON)、微生物量碳(MBC)、微生物量氮(MBN)、NH+4-N和NO-3-N含量。【结果】不同处理条件下,板栗林土壤N2O排放通量均呈显著的季节性变化特征,最高值出现在7月,最低值出现在1月。与对照相比,竹叶处理的土壤N2O年平均通量和年累积排放量分别增加了17.2%和12.8%,而生物质炭处理的土壤N2O年平均通量和年累积排放量分别降低了27.4%和20.5%。竹叶处理的土壤WSON、MBN、NH+4-N及NO-3-N含量增加12.4%、19.1%、8.3%和13%,而生物质炭处理的NH+4-N和NO-3-N含量分别降低了14.1%和18%。在对照、竹叶以及生物质炭处理条件下,板栗林土壤N2O排放通量与土壤温度(表层5 cm处)和WSOC含量均有显著相关性(P 0.05),与土壤MBC含量均无显著相关性。竹叶处理土壤N2O通量与NH+4-N、NO-3-N及WSON含量均有显著相关性(P0.05)。【结论】在不同处理条件下,板栗林土壤N2O排放通量均呈现明显的季节性变化特征,表现为夏季高、 冬季低。输入竹叶可显著增加板栗林土壤N2O排放通量,而输入生物质炭N2O排放通量显著降低;输入竹叶和生物质炭可能是通过影响土壤碳库与氮库特征而影响土壤N2O的排放通量。  相似文献   

19.
Land-use change significantly affects the soil organic C (SOC) dynamics and microbial activities. However, the roles of chemical composition of SOC and enzyme activity in the change in the SOC mineralization rate caused by land-use change are poorly understood. This study aimed to investigate the impact of land-use conversion from natural evergreen broadleaf forests to intensively managed moso bamboo (Phyllostachys edulis) plantations on the pool size and mineralization rate of SOC, as well as the activities of C-cycling enzymes (invertase, β-glucosidase, and cellobiohydrolase) and dehydrogenase. Four paired soil samples in two layers (0–20 and 20–40 cm) were taken from adjacent evergreen broadleaf forest-moso bamboo plantation sites in Lin’an County, Zhejiang Province, China. Soil water-soluble organic C (WSOC), hot-water-soluble organic C (HWSOC), microbial biomass C (MBC), readily oxidizable C (ROC), the activities of C-cycling enzymes and dehydrogenase, and mineralization rates of SOC were measured. The chemical composition of SOC was also determined with 13C-nuclear magnetic resonance spectroscopy. The conversion of broadleaf forests to bamboo plantations reduced SOC stock as well as WSOC, HWOC, MBC, and ROC concentrations (P?<?0.05), decreased O-alkyl, aromatic, and carbonyl C contents, but increased alkyl C content and the alkyl C to O-alkyl (A/O-A) ratio, suggesting that the land-use conversion significantly altered the chemical structure of SOC. Further, such land-use change lowered (P?<?0.05) the SOC mineralization rate and activities of the four enzymes in the 0–20-cm soil. The decreased SOC mineralization rate associated with the land-use conversion was closely linked to the decreased labile organic C concentration and soil enzyme activities. The results demonstrate that converting broadleaf forests to moso bamboo plantations markedly decreased the total and labile SOC stocks and reveal that this conversion decreased the mineralization rate of SOC via changing the chemical composition of SOC and decreasing activities of C-cycling enzymes. Management practices that enhance C input into the soil are recommended to mitigate the depletion of SOC associated with land-use conversion to moso bamboo plantations.  相似文献   

20.
The effects and associated mechanisms of the application of organic residues or their derived biochar on the dynamics of soil organic C and soil CO2 efflux in planted soils are poorly understood. This paper investigated the impact of bamboo leaf and the derived biochar applications on soil CO2 efflux and labile organic C in an intensively managed Chinese chestnut plantation in a 12-month field study. The treatments studied included Control, application of bamboo leaf (Leaf), and application of biochar (Biochar). The Leaf treatment increased (P?2 efflux and concentrations of water-soluble organic C (WSOC) and microbial biomass C (MBC). The Biochar treatment increased soil CO2 efflux and WSOC and MBC only in the first month after application, but such effects diminished thereafter. The annual cumulative soil CO2 emission was increased by 16 % by the Leaf treatment as compared to the Control, but there was no difference between the Biochar and Control treatments. The soil organic C (SOC) storage was increased by biochar addition but not by bamboo leaf addition. An exponential relationship between soil temperature and soil CO2 efflux was observed regardless of the treatment. Soil CO2 efflux was correlated to soil WSOC (P?Q 10) of soil CO2 efflux was ranked as Leaf?>?Biochar?>?Control. In comparison with the application of fresh bamboo leaf, pyrolyzed bamboo leaf (biochar) application decreased CO2 effluxes and increased C sequestration in the soil.  相似文献   

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