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1.
为了解川西北高寒沙地红柳对土壤有机碳及腐殖质碳组分的影响,选取了沙地上修复24 a的红柳灌丛作为研究对象,通过野外调查并结合土壤样品采集和室内分析,研究了川西北沙地红柳灌丛根区(SR)、灌丛中部(SM)、灌丛边缘(SE)、灌丛外部(SO)的0~20,20~40 cm和40~60 cm土层土壤有机碳及腐殖质碳组分变化特征。结果表明:随着距灌丛植株水平距离的增加,土壤有机碳(SOC)、胡敏酸碳(HAC)、富里酸碳(FAC)和胡敏素碳(HMC)含量均呈现下降的特征;0~20 cm表层土壤,灌丛根区、灌丛中部和灌丛边缘土壤有机碳含量分别为灌丛外部的1.86倍、2.35倍和1.63倍,灌丛根区、灌丛中部和灌丛边缘土壤腐殖质碳含量分别为灌丛外部的1.96倍、0.68倍和1.22倍;在距灌丛植株水平距离相同条件下,随土层深度增加,土壤有机碳及腐殖质碳各组分含量呈降低趋势;在灌丛根区,20~40 cm和40~60 cm土层土壤有机碳相对于0~20 cm土层分别降低了32.31%和38.38%,20~40 cm和40~60 cm土层土壤腐殖质碳相对于0~20 cm土层分别降低了49.34%和53.40%。研究得出,红柳灌丛内外土壤有机碳及腐殖质碳组分存在空间异质性分布。  相似文献   

2.
Afforestation is conducive to soil carbon(C) sequestration in semi-arid regions. However, little is known about the effects of afforestation on sequestrations of total and labile soil organic carbon(SOC) fractions in semi-arid sandy lands. In the present study, we examined the effects of Caragana microphylla Lam. plantations with different ages(12-and 25-year-old) on sequestrations of total SOC as well as labile SOC fractions such as light fraction organic carbon(LFOC) and microbial biomass carbon(MBC). The analyzed samples were taken from soil depths of 0–5 and 5–15 cm under two shrub-related scenarios: under shrubs and between shrubs with moving sand dunes as control sites in the Horqin Sandy Land of northern China. The results showed that the concentrations and storages of total SOC at soil depths of 0–5 and 5–15 cm were higher in 12-and 25-year-old C. microphylla plantations than in moving sand dunes(i.e., control sites), with the highest value observed under shrubs in 25-year-old C. microphylla plantations. Furthermore, the concentrations and storages of LFOC and MBC showed similar patterns with those of total SOC at the same soil depth. The 12-year-old C. microphylla plantations had higher percentages of LFOC concentration to SOC concentration and MBC concentration to SOC concentration than the 25-year-old C. microphylla plantations and moving sand dunes at both soil depths. A significant positive correlation existed among SOC, LFOC, and MBC, implying that restoring the total and labile SOC fractions is possible by afforestation with C. microphylla shrubs in the Horqin Sandy Land. At soil depth of 0–15 cm, the accumulation rate of total SOC under shrubs was higher in young C. microphylla plantations(18.53 g C/(m~2·a); 0–12 years) than in old C. microphylla plantations(16.24 g C/(m~2·a); 12–25 years), and the accumulation rates of LFOC and MBC under shrubs and between shrubs were also higher in young C. microphylla plantations than in old C. microphylla plantations. It can be concluded that the establishment of C. microphylla in the Horqin Sandy Land may be a good mitigation strategy for SOC sequestration in the surface soils.  相似文献   

3.
基于新疆古尔班通古特沙漠南缘原始盐生旱生荒漠的3种建群灌木琵琶柴(Reaumuria soongori-ca)、多枝柽柳(Tamarix ramosissima)和梭梭(Haloxylon ammodendron)生态系统下土壤剖面实测数据,分析了土壤有机碳(SOC)和土壤微生物量碳(Mc)的垂直分布特征及其与土壤理化因子的关系。结果表明:3个生态系统类型之间土壤剖面SOC分布状况和含量不存在显著差别,但每个生态系统土壤剖面土层之间存在显著差别。各生态系统土壤上层均存在着一定厚度的SOC富集层,中部(10～30cm)SOC含量迅速下降,下部有机碳含量低而稳定。Mc分布与含量与SOC存在相似的规律。Mc对90cm以上的土壤碳循环起着重要的作用,而对深层次的碳库影响不大,不会对全球变化做出响应,但意义更重要,它们可以更长期保留于土壤中而不释放回大气圈。  相似文献   

4.
Soil organic matter content in water-stable aggregates(WSA) in the arid ecosystems(abandoned agricultural lands especially) of China is poorly understood. In this study, we examined the WSA sizes and stability, and soil organic carbon(OC) and nitrogen(N) contents in agricultural lands with abandonment ages of 0, 3, 12, 20, 30 and 40 years, respectively, in the Minqin Oasis of Northwest China. The total soil OC and N contents at depths of 0–20, 20–40 and 40–60 cm in abandoned agricultural lands were compared to those in cultivated land(the control). Agricultural land abandonment significantly(P0.05) influenced the distribution of MWD(mean weight diameter), and OC and N contents. There were significant increases in MWD and the proportion of macroaggregates(sizes 0.25 mm) as the age of agricultural land abandonment increased. The effect of abandonment ages of agricultural lands on MWD was determined by the changes of OC and N accumulation in WSA sizes 2 mm. The total OC and N contents presented a stratification phenomenon across soil depths in this arid ecosystem. That is, both of them decreased significantly at depths of 0–20 and 40–60 cm while increased at the depth of 20–40 cm. The WSA sizes 0.053 mm had the highest soil OC and N contents(accounting for 51.41%–55.59% and 42.61%–48.94% of their total, respectively). Soil OC and N contents in microaggregates(sizes 0.053–0.25 mm) were the dominant factors that influenced the variations of total OC and N contents in abandoned agricultural lands. The results of this study suggested that agricultural land abandonment may result in the recovery of WSA stability and the shifting of soil organic matter from the silt+clay(0.053 mm) and microaggregate fractions to the macroaggregate fractions. However, agricultural land abandonment did not increase total soil OC and N contents in the short-term.  相似文献   

5.
Soil organic carbon(SOC) and soil inorganic carbon(SIC) are important C pools in the Loess Plateau of Northwest China, however, variations of SOC and SIC stocks under different cultivation practices and nitrogen(N) fertilization rates are not clear in this area. A long-term field experiment started in June 2003 was conducted to investigate the SOC and SIC stocks in a calcareous soil of the Chinese Loess Plateau under four cultivation practices, i.e., fallow(FA), conventional cultivation(CC), straw mulch(SM), and plastic film-mulched ridge and straw-mulched furrow(RF), in combination with three N fertilization rates, i.e., 0(N0), 120(N120), and 240(N240) kg N/hm~2. Results indicate that the crop straw addition treatments(SM and RF) increased the contents of soil microbial biomass C(SMBC) and SOC, and the SOC stock increased by 10.1%–13.3% at the upper 20 cm soil depth in comparison to the 8-year fallow(FA) treatment. Meanwhile, SIC stock significantly increased by 19% at the entire tested soil depth range(0–100 cm) under all crop cultivation practices in comparison to that of soil exposed to the long-term fallow treatment, particularly at the upper 60 cm soil depth. Furthermore, moderate N fertilizer application(120 kg N/hm~2) increased SOC stock at the upper 40 cm soil depth, whereas SIC stock decreased as the N fertilization rate increased. We conclude that the combined application of crop organic residues and moderate N fertilization rate could facilitate the sequestrations of SOC and SIC in the calcareous soil.  相似文献   

6.
Soil carbon(C) and nitrogen(N) play a crucial role in determining the soil and environmental quality. In this study, we investigated the effects of 26 years(from 1984 to 2010) of farmland management on soil organic carbon(SOC) and soil N in abandoned, wheat(Triticum aestivum L.) non-fertilized, wheat fertilized(mineral fertilizer and organic manure) and alfalfa(Medicago Sativa L.) non-fertilized treatments in a semi-arid region of the Loess Plateau, China. Our results showed that SOC and soil total N contents in the 0–20 cm soil layer increased by 4.29(24.4%) and 1.39 Mg/hm2(100%), respectively, after the conversion of farmland to alfalfa land. Compared to the wheat non-fertilized treatment, SOC and soil total N contents in the 0–20 cm soil layer increased by 4.64(26.4%) and 1.18 Mg/hm2(85.5%), respectively, in the wheat fertilized treatment. In addition, we found that the extents of changes in SOC, soil total N and mineral N depended on soil depth were greater in the upper soil layer(0–30 cm) than in the deeper soil layer(30–100 cm) in the alfalfa land or fertilizer-applied wheat land. Fertilizer applied to winter wheat could increase the accumulation rates of SOC and soil total N. SOC concentration had a significant positive correlation with soil total N concentration. Therefore, this study suggested that farmland management, e.g. the conversion of farmland to alfalfa forage land and fertilizer application, could promote the sequestrations of C and N in soils in semi-arid regions.  相似文献   

7.
Soil acidification is a major global issue of sustainable development for ecosystems. The increasing soil acidity induced by excessive nitrogen(N) fertilization in farmlands has profoundly impacted the soil carbon dynamics. However, the way in which changes in soil p H regulating the soil carbon dynamics in a deep soil profile is still not well elucidated. In this study, through a 12-year field N fertilization experiment with three N fertilizer treatments(0, 120, and 240 kg N/(hm~2·a)) in a dryland agroecosystem of China, we explored the soil p H changes over a soil profile up to a depth of 200 cm and determined the responses of soil organic carbon(SOC) and soil inorganic carbon(SIC) to the changed soil p H. Using a generalized additive model, we identified the soil depth intervals with the most powerful statistical relationships between changes in soil p H and soil carbon dynamics. Hierarchical responses of SOC and SIC dynamics to soil acidification were found. The results indicate that the changes in soil p H explained the SOC dynamics well by using a non-linear relationship at the soil depth of 0–80 cm(P=0.006), whereas the changes in soil p H were significantly linearly correlated with SIC dynamics at the 100–180 cm soil depth(P=0.015). After a long-term N fertilization in the experimental field, the soil p H value decreased in all three N fertilizer treatments. Furthermore, the declines in soil p H in the deep soil layer(100–200 cm) were significantly greater(P=0.035) than those in the upper soil layer(0–80 cm). These results indicate that soil acidification in the upper soil layer can transfer excess protons to the deep soil layer, and subsequently, the structural heterogeneous responses of SOC and SIC to soil acidification were identified because of different buffer capacities for the SOC and SIC. To better estimate the effects of soil acidification on soil carbon dynamics, we suggest that future investigations for soil acidification should be extended to a deeper soil depth, e.g., 200 cm.  相似文献   

8.
HAN Huige 《干旱区科学》2015,7(5):636-643
Soil labile organic carbon(C) plays an important role in improving soil quality. The relatively stable fractions of soil organic C(SOC) represent the bulk of SOC, and are also the primary determinant of the long-term C balance of terrestrial ecosystems. Different land use types can influence the distribution patterns of different SOC fractions. However, the underlying mechanisms are not well understood. In the present study, different fractions of SOC were determined in two land use types: a grazed grassland(established on previously cultivated cropland 25 years ago, GG) and a long-term cultivated millet cropland(MC). The results showed that C concentration and C storage of light fractions(LF) and heavy fractions(HF) presented different patterns along the soil profiles in the two sites. More plant residues in GG resulted in 91.9% higher LF storage at the 0–10 cm soil depth, further contributed to 21.9% higher SOC storage at this soil depth; SOC storage at 20–60 cm soil depth in MC was 98.8% higher than that in GG, which could be mainly attributed to the HF storage 104.5% higher than in GG. This might be caused by the long-term application of organic manure, as well as the protection from plough pan and silt- and clay-sized particles. The study indicated that different soil management practices in this region can greatly influence the variations of different SOC fractions, while the conventional tillage can greatly improve the storage of SOC by increasing heavy fractions.  相似文献   

9.
Caatinga is a Brazilian dry ecosystem that occupies around 1 million km2 and is one of the largest tropical dry forests of the world. About 46% of the area that was originally covered has been deforested. Land use can cause pronounced reduction in soil carbon stocks that play a major role in the global carbon cycle. The objective of this study was to improve our understanding of the effect of land use on oxidizable carbon fractions, total carbon stocks and humic substances in different layers of soil in a Brazilian semi-arid region. We analyzed soils from tropical dry forest (TDF), forest succession with Anadenanthera falcata (ANA), with Tabebuia alba (TAB), secondary scrubby regeneration (SCR), and non-irrigated maize (MS). Forests showed larger fractions of more labile carbon, except for TDF. The most recalcitrant fraction of carbon stock, humin fraction stock, with the different land use decreased by 38–53% compared to TDF. Oxidizable carbon fractions, carbon stocks, and humic fraction stocks were able to differentiate the successional land uses and agricultural cover from TDF, mainly in the 0–5?cm layer. Our results show that changes in land use, especially with ANA forest succession, showed a larger labile carbon fraction, indicating easy decomposition and loss. Our results provide an alternative tool for the management of deforested areas in tropical dry caatinga ecosystems. This would contribute to the conservation of dry forest systems and could serve as guideline for sustainable management of agriculturally impacted caatinga areas.  相似文献   

10.
In the last few decades, the Loess Plateau had experienced an extensive vegetation restoration to reduce soil erosion and to improve the degraded ecosystems. However, the dynamics of ecosystem carbon stocks with vegetation restoration in this region are poorly understood. This study examined the changes of carbon stocks in mineral soil(0–100 cm), plant biomass and the ecosystem(plant and soil) following vegetation restoration with different models and ages. Our results indicated that cultivated land returned to native vegetation(natural restoration) or artificial forest increased ecosystem carbon sequestration. Tree plantation sequestered more carbon than natural vegetation succession over decades scale due to the rapid increase in biomass carbon pool. Restoration ages had different effects on the dynamics of biomass and soil carbon stocks. Biomass carbon stocks increased with vegetation restoration age, while the dynamics of soil carbon stocks were affected by sampling depth. Ecosystem carbon stocks consistently increased after tree plantation regardless of the soil depth; but an initial decrease and then increase trend was observed in natural restoration chronosequences with the soil sampling depth of 0–100 cm. Moreover, there was a time lag of about 15–30 years between biomass production and soil carbon sequestration in 0–100 cm, which indicated a long-term effect of vegetation restoration on deeper soil carbon sequestration.  相似文献   

11.
This study was carried out to investigate the effects of long-term cultivation and landscape position on organic carbon content and soil aggregation. Sampling sites were determined based upon land use at the end of 50 years soil use and management, cultivated/annual wheat cropping and grazed pasture, and landscape position in Chaharmahal-va-Bakhtiary province, southwest Iran. Soil samples were collected from the 0–5 cm and 5–15 cm depths in two adjacent fields that have the same slope and aspect. The soil was silty clay at the summit and footslope positions, and was a silty clay loam at the backslope. Wet-sieving analysis and aggregate-size fractionation methods were used to separate the samples into three aggregate fractions (i.e., 2–4.75, 0.25–2, and 0.053–0.25 mm). The treatments were arranged in a factorial design. Land use significantly affected the water-stable aggregate fractions, so that the wet soil stability of the macroaggregates (i.e., 2–4.75 mm) was higher in the pasture, whereas it was greater for the meso-aggregates (i.e., 0.25–2 mm) in the cultivated soils. Cultivation decreased both the wet-aggregate stability and percent of macroaggregates whereas long-term pasture enhanced aggregation. Soil organic carbon (SOC) content within aggregates and primary particles was also significantly influenced by landscape position, land use, and the depth of sampling. The SOC content was higher in clay than those in silt and sand contents. The SOC content decreased as depth increased in all fractions. In general, the highest and lowest wet-stable aggregates were observed on the footslope and backslope positions, respectively.  相似文献   

12.
对黄土高原子午岭油松林不同管理方式下土壤的黑碳(BC)、有机碳(POC)和活性有机碳(LOC)的空间分布和积累进行了研究.结果表明,各种管理方式的油松林其POC、LOC和BC由表层至下层均呈显著的降低规律性.各种管理方式油松林0～10cm土层以BC>POC>LOC,10～20 cm土层中,天然油松林和粗放管理型油松林B...  相似文献   

13.
Corn straw return to the field is a vital agronomic practice for increasing soil organic carbon (SOC) and its labile fractions, as well as soil aggregates and organic carbon (OC) associated with water-stable aggregates (WSA). Moreover, the labile SOC fractions play an important role in OC turnover and sequestration. The aims of this study were to determine how different corn straw returning modes affect the contents of labile SOC fractions and OC associated with WSA. Corn straw was returned in the following depths: (1) on undisturbed soil surface (NTS), (2) in the 0-10 cm soil depth (MTS), (3) in the 0-20 cm soil depth (CTS), and (4) no corn straw applied (CK). After five years (2014-2018), soil was sampled in the 0-20 and 20-40 cm depths to measure the water-extractable organic C (WEOC), permanganate oxidizable C (KMnO4-C), light fraction organic C (LFOC), and WSA fractions. The results showed that compared with CK, corn straw amended soils (NTS, MTS and CTS) increased SOC content by 11.55%-16.58%, WEOC by 41.38%-51.42%, KMnO4-C and LFOC by 29.84%-34.09% and 56.68%-65.36% in the 0-40 cm soil depth. The LFOC and KMnO4-C were proved to be the most sensitive fractions to different corn straw returning modes. Compared with CK, soils amended with corn straw increased mean weight diameter by 24.24%-40.48% in the 0-20 cm soil depth. The NTS and MTS preserved more than 60.00% of OC in macro-aggregates compared with CK. No significant difference was found in corn yield across all corn straw returning modes throughout the study period, indicating that adoption of NTS and MTS would increase SOC content and improve soil structure, and would not decline crop production.  相似文献   

14.
以华北落叶松人工林为对象,研究不同林分密度下(分别为740、1480、2000和2170株.hm-2)各土层的土壤有机碳含量、有机碳密度、养分特征以及它们之间的相关关系。结果表明:土壤有机碳含量及碳密度随着土壤深度增加而减少,呈明显的垂直分布特征;当林分密度增大到2170株.hm-2时,土壤有机碳含量及碳密度显著增加至最大,分别为25.45g.kg-1和15.68kg.m-2,并与740株.hm-2林地土壤有机碳含量及碳密度差异显著。当林分密度由740株.hm-2增加到2170株.hm-2时,各种养分变化规律不尽一致,但当林分密度为2170株.hm-2时,0-60cm深度的土壤全氮、全磷及速效钾含量均保持在一个相对较高的水平,而土壤全钾和有效磷含量仅在0-20cm土层较高。对于落叶松人工林地整个土壤剖面,土壤有机碳含量及碳密度与土壤全氮、全磷、速效钾含量均呈显著或极显著正相关。从林地土壤固碳的角度,建议将华北落叶松人工林的林分密度控制在2170株.hm-2。  相似文献   

15.
Soil carbon pools could become a CO_2 source or sink, depending on the directions of land use/cover changes. A slight change of soil carbon will inevitably affect the atmospheric CO_2 concentration and consequently the climate. Based on the data from 127 soil sample sites, 48 vegetation survey plots, and Landsat TM images, we analyzed the land use/cover changes, estimated soil organic carbon(SOC) storage and vegetation carbon storage of grassland, and discussed the impact of grassland changes on carbon storage during 2000 to 2013 in the Ili River Valley of Northwest China. The results indicate that the areal extents of forestland, shrubland, moderate-coverage grassland(MCG), and the waterbody(including glaciers) decreased while the areal extents of high-coverage grassland(HCG),low-coverage grassland(LCG), residential and industrial land, and cultivated land increased. The grassland SOC density in 0–100 cm depth varied with the coverage in a descending order of HCGMCGLCG.The regional grassland SOC storage in the depth of 0–100 cm in 2013 increased by 0.25×1011 kg compared with that in 2000. The regional vegetation carbon storage(S_(rvc)) of grassland was 5.27×10~9 kg in2013 and decreased by 15.7% compared to that in 2000. The vegetation carbon reserves of the under-ground parts of vegetation(S_(ruvb)) in 2013 was 0.68×10~9 kg and increased by approximately 19.01%compared to that in 2000. This research can improve our understanding about the impact of land use/cover changes on the carbon storage in arid areas of Northwest China.  相似文献   

16.
To ascertain the effects of long-term conservation tillage and residue retention on soil organic carbon(SOC) content and aggregate distribution in a deep soil(>20-cm depth) in a dryland environment,this paper analyzed the SOC and aggregate distribution in soil, and the aggregate-associated organic carbon(OC) and SOC physical fractions. Conservation tillage(reduced tillage with residue incorporated(RT) and no-tillage with residue mulch(NT)) significantly increased SOC sequestration and soil aggregation in deep soil compared with conventional tillage with residue removal(CT). Compared with CT, RT significantly increased the proportion of small macroaggregates by 23%–81% in the 10–80 cm layer, and the OC content in small macroaggregates by 1%–58% in the 0–80 cm layer. RT significantly increased(by 24%–90%) the OC content in mineral-SOC within small macroaggregates in the 0–60 cm layer, while there was a 23%–80% increase in the 0–40 cm layer with NT. These results indicated that:(1) conservation tillage treatments are beneficial for soil aggregation and SOC sequestration in a deep soil in a dryland environment; and(2)the SOC in mineral-associated OC plays important roles in soil aggregation and SOC sequestration. In conclusion, RT with NT is recommended as an agricultural management tool in dryland soils because of its role in improving soil aggregation and SOC sequestration.  相似文献   

17.
The effects of long-term fertilization on pools of soil organic carbon(SOC)have been well studied,but limited information is available on the oxidizable organic carbon(OOC)fractions,especially for the Loess Plateau in China.We evaluated the effects of a 15-year fertilization on the OOC fractions(F1,F2,F3 and F4)in the 0–20 and 20–40 cm soil layers in flat farmland under nine treatments(N(nitrogen,urea),P(phosphorus,monocalcium phosphate),M(organic fertilizer,composted sheep manure),N+P(NP),M+N(MN),M+P(MP),M+N+P(MNP),CK(control,no fertilizer)and bare land(BL,no crops or fertilizer)).SOC content increased more markedly in the treatment containing manure than in those with inorganic fertilizers alone.F1,F2,F4 and F3 accounted for 47%,27%,18% and 8% of total organic carbon,respectively.F1 was a more sensitive index than the other C fractions in the sensitivity index(SI)analysis.F1 and F2 were highly correlated with total nitrogen(TN)and available nitrogen(AN),F3 was negatively correlated with p H and F4 was correlated with TN.A cluster analysis showed that the treatments containing manure formed one group,and the other treatments formed another group,which indicated the different effects of fertilization on soil properties.Long-term fertilization with inorganic fertilizer increased the F4 fraction while manure fertilizer not only increased labile fractions(F1)in a short time,but also increased passive fraction(F4)over a longer term.The mixed fertilizer mainly affected F3 fraction.The study demonstrated that manure fertilizer was recommended to use in the farmland on the Loess Plateau for the long-term sustainability of agriculture.  相似文献   

18.
秸秆带状覆盖对土壤有机碳及其活性组分的影响   总被引：2，自引：0，他引：2  
为了探讨秸秆带状覆盖对旱地不同剖面深度土壤总有机碳(TOC)、可溶性有机碳(DOC)、微生物量碳(MBC)和易氧化态碳(EOC)的影响,于2017—2020年在甘肃省布设秸秆带状覆盖试验,设玉米整秆带状覆盖(TSM)处理,以黑膜双垄沟全膜覆盖(TPM)和传统露地平作(TNM)为对照.结果表明:土壤有机碳和活性碳组分含量...  相似文献   

19.
地表覆盖秸秆和地膜是我国西北旱作农田土壤固碳的重要田间管理措施,但其对土壤碳组分的长期影响尚不明确。基于田间定位试验,设生育期高量秸秆覆盖(9 000 kg·hm-2,HSM)、生育期低量秸秆覆盖(4 500 kg·hm-2,LSM)、夏闲期秸秆覆盖(9 000 kg·hm-2,FSM)、生育期地膜覆盖(PM)和无覆盖对照(CK)共5个处理,研究了秸秆覆盖和地膜覆盖12 a和13 a后旱作冬小麦农田土壤总有机碳(SOC)、颗粒有机碳(POC)、潜在矿化碳(PCM)和微生物量碳(MBC)含量的变化规律。2 a平均结果表明：与CK相比,HSM和LSM处理均显著提高了0～10 cm土层各碳组分含量以及10～20 cm土层SOC、POC、MBC含量,同时还显著提高了0～20 cm土层POC和MBC占SOC的比例;而FSM和PM处理对各土层土壤碳组分含量及其占SOC的比例均无显著影响。土壤碳组分含量相互之间均存在极显著正相关关系。综上可知,长期生育期秸秆覆盖能有效提高旱作冬小麦农田耕层土壤有机碳及其组分含量,且提高覆盖量有助于促进...  相似文献   

20.
土壤盐分对干旱区盐渍土壤碳垂直分布的影响   总被引：1，自引：0，他引：1  
以新疆玛纳斯县盐渍土壤盐分和碳为研究对象,通过野外实地采样调查,分析干旱区盐渍土条件下的土壤盐分、有机碳、无机碳的垂直分布(0~300 cm)特征,探究土壤盐分对土壤碳垂直分布的影响。结果表明:土壤盐分含量随剖面深度增加呈"先增后降"的趋势,有机碳(SOC)含量随剖面深度增加呈下降趋势,无机碳(SIC)含量随剖面深度增加无明显变化规律。土壤剖面中,盐分与有机碳(SOC)含量及密度呈显著正相关(P0.05),在0~100cm土体中相关性最高(r=0.53);盐分与无机碳(SIC)含量及密度在整个土体中呈负相关关系,相关性不显著。  相似文献   

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