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1.
耕作年限对棉田土壤颗粒及矿物结合态有机碳的影响 总被引：5，自引：1，他引：5
研究耕作年限对棉田土壤颗粒及矿物结合态有机碳的影响.以相应荒地为对照,选取南北疆兰州湾、31团和普惠农场3个典型绿洲不同耕作年限土壤为研究对象,应用物理分组方法研究颗粒及矿物结合态有机碳的变化规律.结果表明:耕作有利于棉田土壤总有机碳的积累,耕作(0～5年)总有机碳增加迅速,年均增加在0.65 g/kg以上;颗粒有机物、有机碳和颗粒有机碳的分配比例在耕作0～10年间增加,较荒地分别增加50.12％,263.64％,79.79％,10年后下降.矿物结合态有机碳含量则随耕作年限的延长递增,矿物结合态有机物含量变化趋势与颗粒有机物相反.土壤有机碳在耕作1～10年增加,有利于土壤质量的提高,是荒漠区土壤碳汇,是合理的耕作年限. 相似文献
2.
《Communications in Soil Science and Plant Analysis》2012,43(14):1906-1917
Fundamental knowledge about decomposition, fate of crop residue, and allocation of residue-derived carbon (C) in soil aggregates is essential to understand the C dynamics in soil. The incorporation of C derived from corn residue in water-stable aggregate fractions, particulate organic C (POC), and mineral-associated C (MAC) in soil were examined using the 13C tracer technique. Soil was treated with corn straw at the rate of 1% dry mass of soil brought to 66% of field capacity and incubated for 70 days at 25 °C. Samples were taken at 20, 35, and 70 days and analyzed for water-stable aggregates. Values for POC and MAC were analyzed for total C and 13C enrichment. The addition of corn straw caused a shift in the distribution of recoverable particles with significant decreases in <53-μm silts and clays, microaggregrates (53–250 μm), and smaller macroaggegates (250–2000 μm); however, the large macroaggegates (>2000 μm) increased significantly. Macroaggregates contained greater amount of C than microaggregates. The proportion of 13C recovered in the fractions <53 μm (silt and clay), 53–250 μm, and 250–2000 μm increased during decomposition of corn straw, whereas there was no significant change in >2000-μm fraction. Most (70–76%) of the soil organic C was affiliated with MAC (<53 μm). Carbon (13C) derived from corn straw decreased in POC but increased in MAC as decomposition proceeded. In the long term, microaggregate fraction appears to be involved in storage and stabilization of the C derived from corn straw and is important for soil quality and soil C sequestration point of view. 相似文献
3.
[目的] 为了探究针阔混交改造措施对红壤侵蚀区恢复马尾松林土壤碳库稳定性的影响。[方法] 以福建长汀不同恢复年限(Y10、Y20、Y41)马尾松林(CF)和相对应的针阔改造林(MF)作为研究对象,通过物理分组方法将土壤有机碳分为颗粒态有机碳(POC)和矿质结合态有机碳(MAOC),分析林分改造过程对不同土壤剖面土壤有机碳组分的影响。[结果] (1)相比于马尾松纯林,混交林显著增加MAOC和0—10 cm土层SOC、POC含量,并避免长期恢复马尾松林MAOC的消耗;(2)林分改造显著降低Y20-MF中10—20,40—60 cm土层及Y41-MF中0—20 cm土层POC/SOC,但显著增加Y10-MF中20—60 cm土层及Y41-MF中0—10 cm土层MAOC/SOC;(3)随着年限的增加,混交林中0—10 cm土层MAOC/SOC持续增加,POC/SOC显著降低,而马尾松林则相反;(4)线性拟合发现,POC、MAOC均与SOC呈显著正相关,但混交林土壤SOC增加更多依赖MAOC的增加,而马尾松土壤SOC的增加更多的以非稳定性碳组分(POC)为主;(5)冗余分析表明,DOC、TN、TP、NH+4共同解释碳组分变化的66.2%,表明林分改造后土壤养分有效性的增加是混交林MAOC积累的关键。[结论] 亚热带红壤侵蚀区林分改造通过提升土壤养分有效性,增加稳定碳库的积累从而避免长期恢复过程中土壤碳库流失。 相似文献
4.
对重庆中梁山岩溶山地不同土地利用方式下0-40cm土壤颗粒有机碳和矿物结合态有机碳的含量和分布特征进行了研究.结果表明:不同土地利用方式土壤有机碳含量平均值表现为:林地>菜地>草地>橘园地>弃耕地.除橘园地外,其它各土地利用类型土壤细颗粒有机碳(FPOC)含量大于粗颗粒有机碳(CPOC).不同利用方式土壤颗粒有机碳含量在剖面层次中表现不同.0-20cm表层土壤CPOC含量表现为:橘园地>草地>菜地>林地>弃耕地,差异较大.土壤FPOC含量表现为:林地>草地>菜地>橘园地>弃耕地;20-40cm土壤CPOC和FPOC最高值出现在菜地,最低值出现在弃耕地.不同土地利用方式土壤矿物结合态有机碳(MOC)含量和土壤有机碳含量分布特征一致.除橘园地外土壤各组分有机碳分配比例大致表现为:MOC/SOC>CPOC/SOC>FPOC/SOC.相关分析表明,不同土地利用方式土壤SOC和POC呈正相关,相关性不一致.林地和草地呈极显著相关(P<0.01),弃耕地呈显著相关(P<0.05),菜地和橘园地相关性不显著.表明人为干扰和耕作措施会影响POC对SOC的贡献. 相似文献
5.
This study was conducted to assess the influence of biowaste compost on soil aggregation and soil organic carbon (SOC) stabilization, in a conventional tillage agro-ecosystem. Four treatments were involved: biowaste compost (Com), fertilizers nitrogen, phosphorus and potassium (NPK) (Min), biowaste compost plus mineral N (ComN) and unfertilized control (Cnt). Compared to the control, after four years, the amount of macroaggregates decreased by 23% and 69% for Com and ComN, while SOC stock increased by 17% and 10%, respectively. Most part of the SOC increases were stored in free-microaggregates and were made up for more than 70% by mineral-associated organic carbon (MOC), while no significant variation of particulate organic C (POC) was observed. Therefore, the biowaste compost application rates and time that were practiced in the studied agro-ecosystem were effective for C sequestration, but not enough to improve the macroaggregation and the POC protection. 相似文献
6.
土壤颗粒态有机碳(POC)和矿物结合态有机碳(MAOC)是土壤有机碳库的主要组成,了解施用生物炭对其含量变化及其在土壤总有机碳中的占比和化学组成特征,对认识土壤有机碳动态变化具有重要意义。
于2019年,分别在杭州市富阳区的酸性和石灰性水稻土上进行猪粪生物炭施用量和方法定位试验,种植制度为单季水稻。试验设置6个处理：常规施化肥(NPK),NPK基础上施用猪粪4.5 t/(hm2·a) (SM),NPK基础上施用猪粪生物炭4.5 t/(hm2·a) (SBc1)、11.25 t/(hm2·a) (SBc2)、22.5 t/(hm2·a) (SBc3),以及猪粪生物炭一次性施用112.5 t/hm2 (SBc4)。2021年(第3年)水稻收获后,采集0—20 cm耕层土壤样品,分析其基本理化性质,并将土壤样品分为250～ 2000 μm (粗颗粒态有机物),53～250 μm (细颗粒态有机物)和 <53 μm (矿物结合态有机物) 3个粒级,分析各粒级土壤中有机碳含量以及占比,并采用傅里叶红外光谱仪分析了各粒级土壤有机碳的特征光谱,以特征光谱峰值半定量性的评估了有机碳组成的变化。
与SM处理相比,酸性水稻土中SBc3、SBc4处理土壤有机碳含量分别显著增加了49.4%和103.3%,石灰性水稻土中土壤有机碳含量分别增加了42.2%和53.0%。与SM处理相比,4个猪粪生物炭处理显著增加了酸性水稻土粗颗粒态有机碳(C-POC)含量137.8%～554.1%,细颗粒态有机碳(F-POC)含量37.6%～85.2% (
对于较高的猪粪生物炭施用量,不论一次性施用还是逐年施用均可显著增加水稻土总有机碳含量,且粗颗粒有机碳增加幅度大于细颗粒,而对矿物结合态有机碳含量无显著影响。施用猪粪生物炭对土壤有机碳主要组成有机化合物无显著影响,但会增加酸性水稻土有机碳的稳定性,而降低石灰性水稻土有机碳的稳定性。相同施用量下,猪粪生物炭提高酸性水稻土有机碳含量的作用高于石灰性水稻土。本试验结果可为猪粪生物炭在农田的科学应用提供技术支撑和理论依据。
7.
土壤颗粒态有机碳(POC)和矿物结合态有机碳(MAOC)是重要的土壤碳库,其比例的变化决定土壤有机碳的周转速率及稳定性。探讨沙地生物土壤结皮发育过程中颗粒态有机碳和矿物结合态有机碳的含量、分配比例和差异性特征,对于深刻认识初始土壤形成过程中有机碳库形成、稳定机制具有重要意义。选择神木市六道沟流域生物土壤结皮4个发育阶段(藻结皮、藻结皮+少量藓结皮、藓结皮+少量藻结皮、藓结皮)为研究对象,裸沙作为对照,研究生物结皮层及结皮层下层0—2 cm, 2—10 cm, 10—20 cm土层土壤颗粒态和矿物结合态有机碳的变化特征。结果表明：(1)在BSCs土层,POC的增加速率大于MAOC,MAOC处于饱和状态;(2)在BSCs和0—2 cm土层,以微生物源有机碳为主导的MAOC主要贡献有机碳积累,在2—10 cm和10—20 cm土层,以植物源有机碳为主导的POC主要贡献有机碳积累;(3) POC和MAOC含量随土层增加而降低,随着生物土壤结皮发育而增加;(4) POC和MAOC与SOC均有显著的正相关关系,表明结皮定殖和发育显著促进了土壤有机碳积累。这些结果表明生物土壤结皮的定殖和发育能够显著... 相似文献
8.
连续五年生物垃圾堆肥施用后地中海蔬菜种植系统中土壤有机碳的变化 总被引：1，自引：0，他引：1
Biowaste compost can influence soil organic matter accumulation directly or indirectly. A 5-year experiment was conducted to assess the influence of biowaste compost on the process of soil aggregation and soil organic carbon(SOC) accumulation in a Mediterranean vegetable cropping system. The study involved four treatments: biowaste compost(COM), mineral NPK fertilizers(MIN), biowaste compost with half-dose N fertilizer(COMN), and unfertilized control(CK). The SOC stocks were increased in COM, COMN, and MIN by 20.2, 14.9, and 2.4 Mg ha~(-1)over CK, respectively. The SOC concentration was significantly related to mean weight diameter of aggregates(MWD)(P 0.05, R~2= 0.798 4) when CK was excluded from regression analysis. Compared to CK, COM and COMN increased the SOC amount in macroaggregates( 250 μm) by 2.7 and 0.6 g kg~(-1)soil, respectively, while MIN showed a loss of 0.4g kg~(-1)soil. The SOC amount in free microaggregates(53–250 μm) increased by 0.9, 1.6, and 1.0 g kg~(-1)soil for COM, COMN, and MIN, respectively, while those in the free silt plus clay aggregates( 53 μm) did not vary significantly. However, when separating SOC in particle-size fractions, we found that more stable organic carbon associated with mineral fraction 53 μm(MOM-C) increased significantly by 3.4, 2.2, and 0.7 g kg~(-1)soil for COM, COMN, and MIN, respectively, over CK, while SOC amount in fine particulate organic matter(POM) fraction(53–250 μm) increased only by 0.3 g kg~(-1)soil for both COM and COMN, with no difference in coarse POM 250 μm. Therefore, we consider that biowaste compost could be effective in improving soil structure and long-term C sequestration as more stable MOM-C. 相似文献
9.
Jinhua ZHAO Lin CHEN Guixiang ZHOU Fang LI Jiabao ZHANG Congzhi ZHANG Donghao MA Biao FENG 《土壤圈》2024,34(5):941-950
Macroaggregate organic carbon (Macro-OC) accumulation in paddy soils is of great significance in promoting multiple agroecosystem services. However, the effects of different fertilization practices on Macro-OC accumulation in paddy soils at the regional scale have not been comprehensively investigated. Here, we conducted long-term fertilization field experiments at four sites, Taoyuan, Wangcheng, Jinxian, and Suzhou, in the subtropical area of China to reveal the effects of inorganic and organic-inorganic (OIF) fertilization on Macro-OC accumulation and its relationships with important microbial traits (the abundance ratio of GH48:cbhI genes and the richness of keystone bacterial taxa) in paddy soils. The results showed that long-term fertilization (particularly OIF) significantly increased the content of Macro-OC, which mainly consisted of particulate organic carbon (C). Organic-inorganic fertilization decreased the percentage of O-alkyl C but increased the percentages of alkyl, aromatic, and phenolic C. Organic-inorganic fertilization promoted the abundance of the bacterial cellulose-degrading gene GH48 retrieved from macroaggregates. The orders Anaerolineales, Bacillales, and Clostridiales were identified as keystone bacterial taxa in macroaggregates and were significantly correlated with the physical fraction and chemical structure of Macro-OC. Structural equation modeling revealed that fertilization-induced changes in soil pH and C:N ratio affected the richness of Anaerolineales, Bacillales, and Clostridiales, which was strongly associated with the increase of percentages of aromatic and phenolic C and further facilitated Macro-OC accumulation. Together, these results suggested that OIF promoted Macro-OC accumulation associated with key bacterial populations in paddy soils. The results provide an important basis for boosting soil C accrual in the subtropical rice-growing areas. 相似文献
10.
Soil density fractionation is a common tool to separate organic matter of different function and turnover. But it has not been tested so far how much soil material is necessary to obtain reproducible results. A reduction of chemicals like polytungstate would further save valuable resources. Here, we show that soil weight reduction from 25 to 5 g was not significantly affecting fractionation results. Compared to the commonly used 10–25 g, this corresponds to a saving of resources of up to 80%. 相似文献
11.
长期培肥下红壤有机碳组成与团聚体稳定性的关系 总被引：5，自引：0，他引：5
为研究培肥措施对红壤有机碳组成和团聚体稳定性的影响,以及有机碳与团聚体稳定性的关系,通过长期定位实验,选取不同施肥措施(未培肥CK、化肥NPK、化肥+秸秆NPKS和粪肥AM)下的典型红壤为研究对象,分析土壤有机碳组成和团聚体稳定性差异,揭示3种施肥措施下不同层次的有机碳组成和团聚体稳定性的变化规律.结果表明,3种施肥措施均可以提高土壤表层(0 ～25 cm)有机碳质量分数(尤其是颗粒有机碳),其中AM效果最显著,NPKS次之.不同施肥措施下红壤不同层次的团聚体稳定性顺序为AM＞ NPKS＞ NPK＞ CK.与CK相比,AM处理对表下层(5～15 cm)土壤的总有机碳和团聚体稳定性的提高效果最显著.回归分析表明,颗粒有机碳(POC)与湿筛法平均质量直径以及快速湿润(FW)、慢速湿润(SW)、预湿润震荡(WS)3种处理的平均质量直径的相关性最好(R2 =0.79、0.80、0.66、0.81),说明相对于其他组分,颗粒有机碳更有利于降低消散作用以及抵抗机械破碎进而增强团聚体稳定性,是间接评价土壤团聚体稳定性的良好指标. 相似文献
12.
S. B. Dikgwatlhe F. L. Kong Z. D. Chen R. Lal H. L. Zhang F. Chen 《Soil Use and Management》2014,30(4):496-506
Soil degradation and associated depletion of soil organic carbon (SOC) have been major concerns in intensive farming systems because of the subsequent decline in crop yields. We assessed temporal changes in SOC and its fractions under different tillage systems for wheat (Triticum aestivum L.) – maize (Zea mays L.) cropping in the North China Plain. Four tillage systems were established in 2001: plow tillage (PT), rotary tillage (RT), no‐till (NT), and plow tillage with residues removed (PT0). Concentrations of SOC, particulate organic carbon (POC), non‐POC (NPOC), labile organic carbon (LOC), non‐LOC (NLOC), heavy fraction carbon (HFC) and light fraction carbon (LFC) were determined to assess tillage‐induced changes in the top 50 cm. Concentrations of SOC and C fractions declined with soil depth and were significantly affected by tillage over time. The results showed that SOC and its fractions were enhanced under NT and RT from 0 to 10 cm depth compared with values for PT and PT0. Significant decreases were observed below 10 cm depths (P < 0.05) regardless of the tillage system. The SOC concentration under NT for 0–5 cm depth was 18%, 8%, and 10% higher than that under PT0 after 7, 9, and 12 yr of NT adoption, respectively. Apparent stratification of SOC occurred under NT compared with PT and PT0 for depths >10 cm. All parameters were positively correlated (P < 0.01); linear regressions exhibited similar patterns (P < 0.01). Therefore, to maintain and improve SOC levels, residue inputs should be complemented by the adoption of suitable tillage systems. 相似文献
13.
The effects of continuous application of cattle manure on the quantity and quality of soil organic matter (OM) were investigated in an Ando soil (Melanudand). Surface soil samples were periodically taken from NPK and NPK+ manure (80, 160, and 320 Mg ha-1 y-1) plots over a period of 20 y. Particulate (>53 µm) and mineral-associated <53 µm) OM fractions were separated from the soil samples by sieving after:mechanical dispersion. For the NPK treatment, both the organic C and total N concentrations of the whole soil continued to decrease, the reduction reaching about 10% after 20 y. Manure application at the rate of 80 Mg ha-1 y-1 did not lead to an increase in the amounts of organic C and total N in the whole soil. In contrast, both the organic C and total N concentrations increased by the application of 160 and 320 Mg ha-1 y-1 manure. Manure application at the rate of 320 Mg ha-1 y-1 increased the organic C concentration by 30% and total N concentration by 48% after 20 y. The decrease in the organic C and total N concentrations in soil with NPK fertilization was attributed to a decrease in the amount of mineralassociated OM. Manure application increased significantly the amount of particulate OM, while it did not affect the amount of mineral-associated OM. It also resulted in a decrease in the C/N ratio of soil OM, especially of the particulate OM. The analysis of humic acids showed that manure application induced a decrease in the degree of humification and an accumulation of high molecular weight components. The quantitative'and qualitative changes of OM in the Ando soil upon manure application were mainly due to the accumulation of manure-derived particulate OM. 相似文献
14.
Chen Yanlong Zhang Yuhan Xu Risheng Song Jianxiao Ailei Chen Chen Fan Liang Yanru Guo Di Tang Xin Qin Zemin Tian Xiaohong Li Cui Wang Yuheng 《Land Degradation u0026amp; Development》2023,34(14):4428-4440
Anaerobic soil disinfestation (ASD) is a short-term practice to conquer soil degradation, yet its effects on soil organic carbon (SOC) and its composition remain unclear. A field experiment was conducted in degraded greenhouse soils (C3) that were previously used for production of vegetable (VP) and flower (FP), with three treatments (i.e., control, ST [maize straw addition [C4]] and ASD [both ST and water flooding]) for 21 days. Results indicated that the control soil lost 1.3 Mg C ha−1 in VP and 0.94 Mg C ha−1 in FP, while ST increased SOC storage by over 1.0 Mg C ha−1 in both VP and FP. The ASD increased SOC storage by over 2.0 Mg C ha−1 by forming new SOC and decreasing old SOC loss. Additionally, ASD increased OC concentration in particulate size fractions, particularly in particulate organic matter (POM) with lower basal respiration, and higher hydrophobicity as indicated by an increased ratio of C–H/C=O from POM observed by FTIR. The SEM-EDS found an enhanced C signal in particle size fractions, especially in POM. Overlap of C, O, Si, Ca, and Fe in mineral-associated organic matter upon ASD indicated the possible crosslinking between intra-OC and minerals containing O, Si, Ca, and Fe. The ASD also controlled soil salinization and the pathogen Fusarium oxysporum, resulting in increased tomato yields in both VP and FP. Overall, apart from increasing tomato yields, ASD can enhance SOC storage by increasing OC in particle size fractions within a short term. 相似文献
15.
16.
外源有机碳对黑土有机碳及颗粒有机碳的影响 总被引：3，自引：3，他引：3
为了阐释外源有机碳在土壤有机碳运转中的作用机制,以黑土为供试材料,进行了5年的室外培养试验,并结合室内全土及颗粒组分单独矿化培养试验,研究了不同外源有机碳对黑土有机碳(SOC)、颗粒有机碳(POC)含量及其矿化特征的影响。试验包括单施化肥、牛粪配施化肥、鸡粪配施化肥、秸秆配施化肥和树叶配施化肥5个处理。结果表明:(1)单施化肥黑土SOC的损失主要来源于POC的损失,外源有机碳有利于SOC和POC的累积,与对照相比,禽畜粪便处理的SOC和POC平均增加幅度分别为16.6%和27.8%,植物残体处理的SOC和POC平均增加幅度分别为27.0%和46.4%;(2)一级动力学方程能较好地描述SOC和POC的矿化动态(R~20.9),且POC比SOC易矿化,POC的60d累积矿化量是SOC的3倍以上;(3)禽畜粪便处理和植物残体处理的POC平均矿化率分别为31.5%和29.8%,禽畜粪便处理的POC更易矿化;(4)外源有机碳有效降低了黑土有机碳的矿化,尤其是牛粪,其SOC矿化率为1.9%,比对照低了3.4%,其POC矿化率为24.8%,比对照低17.4%;(5)外源有机碳在黑土中的碳累积能力表现为树叶秸秆牛粪鸡粪。 相似文献
17.
研究高寒湿地植被退化过程中土壤颗粒有机碳（POC）的变化特征及其影响因素,可为深入理解高寒湿地土壤碳库动态对气候变化和人类活动的响应提供基础数据。以甘肃尕海湿地区内不同植被退化程度的沼泽草甸（未退化 ND、轻度退化 SD、中度退化 MD和重度退化 HD）湿地土壤为研究对象,研究了植被退化过程中湿地土壤POC在2016年和2017年生长季的变化特征及其与环境之间的关系。结果表明：（1）植被退化显著降低了湿地表层（0～10和10～20 cm）土壤 POC含量,而对其他土层（20～40、40～60、60～80和80～100 cm）土壤POC含量影响不显著。（2）随生长季的推移,表层土壤 POC含量呈现先降后升的趋势,但其他土层土壤POC含量无明显变化,2016年土壤POC含量和变幅均高于2017年。（3）采样时间、植被退化和土壤深度均对POC影响显著,同时对土壤POC有显著交互作用。（4）全氮和地下生物量是影响土壤有机碳组分变化的主导因素。植被退化可能导致青藏高原湿地表层土壤碳库中积累的大量POC损失,使青藏高原湿地成为一个潜在碳源。 相似文献
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土壤团聚体作为土壤结构性状的重要指标,对土壤孔隙、持水、保水等状况都有重要影响;土壤团聚体有机碳除了反映土壤固碳状况外,还与团聚体的稳定性能密切相关,研究森林土壤团聚体及其有机碳状况,旨在为合理利用土壤、提高人工林水源涵养功能提供依据。为此,以福建省洋口国有林场不同林龄杉木人工林(幼龄林、中龄林、成熟林)土壤为研究对象,通过野外调查、采样和室内分析,研究不同林龄杉木人工林土壤团聚体及其有机碳变化特征。结果表明:不同林龄杉木人工林对土壤团聚体及其有机碳具有重要影响,成熟林土壤大团聚体含量、团聚体平均重量直径(MWD)、团聚体有机碳含量及贡献率均分别大于幼龄林、中龄林;不同林龄的土壤水稳性团聚体均以大团聚体(粒径0.25 mm)为主,占59.57%～80.97%,粒径0.053 mm的仅占0.80%;土壤团聚体有机碳贡献率也以大团聚为主,其中以2～0.25 mm粒级贡献率最高,达58.43%;另外,土壤有机碳含量与团聚体MWD呈显著正相关,且具有明显的垂直变化特征,即随土层加深而下降。因此,土壤有机碳对团聚体稳定性具有积极作用,不同林龄土壤团聚体稳定性及有机碳变化规律为成熟林幼龄林中龄林。 相似文献
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土壤胶结物质分布特征及其对黄土大团聚体稳定性的影响 总被引：6，自引：3，他引：6
通过对子午岭林区顶级植被辽东栎群落0—100cm土层有机无机胶结物质的含量与类型、土壤大团聚体稳定性进行野外调查采样与室内测定,对胶结物质含量与分布及其对大团聚体稳定性的影响进行了研究,探讨了不同胶结物质对大团聚体稳定性的影响。结果表明:(1)土壤有机碳和碳酸钙含量在剖面上呈现出完全相反的分布规律。有机碳含量随土层的加深而降低,其中0—20cm土层中有机碳含量显著高于20—100cm土层;而碳酸钙含量随土层的加深而增加,其中20—100cm土层中碳酸钙含量显著高于0—20cm土层。土壤黏粒含量随土层的加深逐渐增加,但总体上变化不明显。(2)土壤大团聚体稳定性随土层的加深而降低,其中在20—70cm土层中大团聚体稳定性随土壤深度的增加变化最为剧烈(与0—20cm土层相比,破坏率增加了581.00%)。40—100cm土层中大团聚体破坏率是0—20cm土层中的7.25倍,表明表层大团聚体稳定性远远高于底层。(3)黄土大团聚体稳定性的提高主要取决于土壤有机碳含量。而在有机碳组分中,矿物结合态有机碳对大团聚体稳定性的提高起最直接作用。研究结果揭示了黄土主要胶结物质在土壤剖面中的分布特征,明确了矿物结合态有机碳是直接影响黄土大团聚体稳定性最强烈的胶结物质,这为培育良好的土壤结构体提供了一定的科学依据。 相似文献