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1.
Soil Erodibility and Physicochemical Properties of Collapsing Gully Alluvial Fans in Southern China 总被引：1，自引：0，他引：1
In southern China, collapsing gully erosion produces massive deposits of sediment on the plough layer of alluvial fan farmland, leading to reduced nutrients, increased erodibility, and even desertification. The aim of this study was to investigate soil erodibility (the factor K in the universal Soil Loss Equation, USLE) and physicochemical properties of the alluvial fans of the most severe collapsing gully erosion areas (Hubei, Jiangxi, Fujian, and Guangdong provinces) in southern China. The soils of the collapsing gully alluvial fans had a higher bulk density, but a lower total porosity, saturated water content, and silt and clay fractions than the control (CK) soils from the farmland without desertification. Soil quality gradually decreased from fan edge to fanhead. Significant decreases were found in soil pH, organic matter, cation exchange capacity, and total potassium, nitrogen, and phosphorus, as well as available nitrogen, phosphorus, and potassium, resulting in a gradual decrease in soil nutrients from the fanedge to the fanhead. Soil erodibility was greatest in the fanhead, and soil erodibility K values of the alluvial fans were 53.71%, 66.28%, 67.53%, and 71.68 % greater than that in those of the CK soils of Hubei, Jiangxi, Fujian, and Guangdong, respectively, indicating a significant correlation between the soil erodibility K values and physicochemical properties, particularly sand fraction and organic matter content. The results provide new insights into the relationship between soil physicochemical properties and erodibility of alluvial fans, and suggest that improving soil structure might increase soil fertility in the collapsing gully alluvial fan farmland. 相似文献
2.
Historical perspective of soil classification in Japan from Max Fesca's soil classification in 1882 to the “Unified Soil Classification System of Japan (2002)” was outlined, aiming at reviewing the progress in soil classification. The evolution can be divided into the following five aspects: 1) Max Fesca's soil texture survey and soil classification from the agro-geological point of view under the influence of the German school; 2) Introduction of the concept of pedology into the classification under the influence of the Russian school led by Dokchaev; 3) Brief history of the classification of Andosols which has exerted a considerable influence on soil classification worldwide; 4) Soil classifications developed through the implementation of national soil survey projects to independently evaluate land suitability for the cultivation of paddy rice, upland crops, and for forest establishment; 5) Attempts to develop a comprehensive soil classification system in order to unify soil classification systems for the above-mentioned land uses from 1963 to the present. 相似文献
3.
土壤可蚀性研究现状及展望 总被引：10，自引：0，他引：10
<正> 土壤可蚀性(soil erodibility)是指土壤是否易受侵蚀破坏的性能,也就是土壤对侵蚀介质剥蚀和搬运的敏感性。与侵蚀营力一样,土壤可蚀性是影响土壤侵蚀量大小的又一个重要因子。在水土保持学科中,我国习惯上把“水”和“土”并列使用,而国际上则用“soil loss”、“soil erosion”、“soil conservation”或“soil and water conservation”等术语。显然,土壤是水土保持学科的重点。另一方面,土壤侵蚀营力等是土壤流失过程中的外部因素,而土壤性质才是内在因素,因此,水土保持学科中核心的也是重要的问题,应该是土壤保护。土壤可蚀性研究在水土保持研究工作中具有重要意义,国际上把土壤可蚀性研究一直作为水土保持学科研究的重要内容之一。 相似文献
4.
中国东北黑土养分空间异质性 总被引：32，自引：0，他引：32
Patterns of soil organic carbon (SOC) storage and density in various soil types or locations are the foundation for examining the role of soil in the global carbon cycle. An assessment of SOC storage and density patterns in China based on soil types as defined by Chinese Soil Taxonomy (CST) and the recently compiled digital 11000 000 Soil Database of China was conducted to generate a rigorous database for the future study of SOC storage. First, SOC densities of 7292soil profiles were calculated and linked by soil type to polygons of a digital soil map using geographic information system resulting in a 11000 000 SOC density distribution map of China. Further results showed that soils in China covered 9 281 ×103 km2 with a total SOC storage of 89.14 Gt and a mean SOC density 96.0 t ha-1. Among the 14 CST orders, Cambosols and Argosols constituted high percentage of China's total SOC storage, while Andosols, Vertosols, and Spodsols had a low percentage. As for SOC density, Histosols were the highest, while Primosols were the lowest. Specific patterns of SOC storage of various soil types at the CST suborder, group, and subgroup levels were also described. Results obtained from the study of SOC storage and density of all CST soil types would be not only useful for international comparative research, but also for more accurately estimating and monitoring of changes of SOC storage in China. 相似文献
5.
金沙江干热峡谷中退化的土壤生态系统生物学特征初探 总被引：4，自引：0，他引：4
Distribution characteristics of soil animals,microorganisms and enzymatic activity were studied in the dry red soil and Vertisol ecosystems with different degradation degrees in the Yuanmou dry hot valley of the Jinsha River,China.Results showed that Hymenoptera,Araneae and Collembola were the dominant groups of soil animals in the polts studied.The numbers of groups and individuals and density of soil animals in the dry red soil series were higher than those in the Vertisol series,and the numbers of individuals and density of soil animals decreased with the degree of soil degradation.Bacteria dominated microbiococnosis not only in the dry red soils but also in the Vertisols.Microbial numbers of the dry red soil series were higher than those of Vertisol series,and decreased with the degree of soil degradation.The activities of catalase,invertase,urease and alkaline phosphatase declined with the degradation degree and showed a significant decline with depth in the profiles of both the dry red soils and the Vertisols,but activities of polyphenol oxidase and acid and neutral phosphatase showed the same tendencies only in the Vertisols.It was concluded that the characteristics of soil animals,microorganisms and enzymatic activity could be used as the bio-indicators to show the degradation degree of the dry red soils and Vertisols.Correlation among these soil bio-indicators was highly significant. 相似文献
6.
土壤结构改良剂对皖南旱地红壤水分特征的影响 总被引：4，自引：0，他引：4
[目的]研究土壤结构改良剂对皖南旱地红壤孔隙、容重及水分特征的影响,为皖南旱地红壤改良、提高土壤持水保水与抗旱保墒性能提供依据。[方法]采用硅藻土(通气性Si改良剂)、泡沫沙类改良剂(T20)和无机矿石类改良剂(G20)等3种土壤结构改良剂,设置1%,2%,5%与10%的4个添加比例,进行土壤物理性状与水分特征测试。[结果]硅藻土与T20均可显著降低土壤容重,而G20在添加5%与10%时才显著降低;硅藻土处理土壤毛管孔隙度由52.1%增加到91.3%,优于T20和G20;硅藻土与T20的吸湿系数与凋萎湿度随用量呈先增加而后下降,而G20则随添加量增加而增加;土壤的饱和持水量与田间持水量均随土壤结构改良剂添加量的增加而增加,以硅藻土增加最多,T20次之,G20最少。随改良剂用量增加,土壤有效水及难效水均呈增加趋势,其中,硅藻土处理的难效水增加量显著高于T20与G20处理。[结论]改良皖南旱地土壤水分需要根据改良剂材料的种类与用量来进行合理施加,必要时可以组合搭配使用,从而达到最优效果。 相似文献
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渭北旱塬侵蚀退化土壤生产力的恢复与评价 总被引：3，自引：0，他引：3
土壤侵蚀会降低生产力,威胁农业生产,因此,对土壤生产力进行恢复和评价具有重要意义。通过人工剥离熟土层,模拟研究不同侵蚀程度下的土壤生产力,选取施肥和覆盖表土2种恢复措施,对其土壤生产力的恢复情况展开研究并进行评价。结果表明:1)土壤侵蚀能够使土壤的理化性状恶化,施肥和覆土均能很好地改善土壤密度和孔隙度等,并能够增加土壤有机质及其他养分的质量分数。2)土壤侵蚀会降低作物产量,在不施肥下,每侵蚀1cm熟土层,玉米产量平均下降1.27%,施肥下每侵蚀1 cm熟土层,玉米产量比对照平均增加0.87%;而每覆盖1cm熟土层,玉米产量平均增加0.91%,但并不能完全补偿侵蚀造成的产量损失。3)利用土壤生产力指数模型(PI模型)计算出了不同措施下的生产力指数,发现:无肥下侵蚀的生产力指数最低,平均每侵蚀1 cm熟土层,生产力指数下降2.17%,施肥下平均每侵蚀1 cm熟土层,生产力指数比无肥增加1.09%,而平均每覆盖1 cm熟土,生产力指数增加1.29%;表明覆土较施肥更易提高土壤生产力。4)对产量和生产力指数进行相关性分析,得出二者具有很好的正相关关系,说明用生产力指数来衡量土壤生产力的高低是可行的。 相似文献
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石羊河中游荒漠绿洲区土壤水分的分布特征 总被引：5，自引：0，他引：5
通过田间实验,研究了不同土壤层颗粒组成、土壤水分的分布特征及不同土壤层间土壤水分的关联性。结果表明：（1）土壤颗粒组成决定了不同土壤层的持水性能,是导致土壤水的分布及运动方式发生变化,影响水分在土壤中滞留时间的根本原因,土壤层中的砂砾所占百分数越大,粘粒含量就越少,含水率就越小,壤土中的土壤水分滞留时间远大于砂质土壤。（2）试验区3m内土壤层可分为水分散失带、水分滞留带和水分过渡带,水分滞留带是土壤水分暂时贮存的重要土层,也是为植被提供深层土壤水分的直接来源,对植被的生长及农作物生产有重要的影响,而土壤中粉砂质粘粒含量的高低决定了水分过渡带的形成及其对水分调节能力的强弱。（3）在地下水深埋区,灌溉是土壤水分重要的补给来源,也是影响土壤水分重分布的主要因素,在天然降水量大部分为无效降水的情况下,灌溉水是土壤水唯一的补给源。补给水分滞留带的灌溉水量的多寡,直接影响着水分滞留带的调节能力及作物和植被的生长。 相似文献
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不同改良剂对宁夏地区盐碱土土壤结构的影响 总被引：4，自引：1，他引：3
采用玉米室内盆栽试验的方法,研究了宁夏回族自治区石嘴山市平罗县姚伏镇大兴墩村的盐碱土在施用硫磺、有机肥、石膏、PAM等不同土壤改良剂对土壤结构的影响.研究结果表明,4类改良剂均有效降低了土壤容重,土壤空隙度随之增加,土壤物理结构的改善与水分利用相互配合,共同促进了当地盐碱土的改良;硫磺的最佳用量确定为在30.45 g/盆,并需要注意土壤通气性,防止发生反硫化作用,对玉米根系产生毒害;综合而言,PAM改良效果最佳.其次是石膏和S3处理. 相似文献
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我国几种农田土壤硝化势的研究 总被引：27，自引：3，他引：27
对我国三种土壤类型的农田土壤剖面的硝化势进行研究 ,结果表明 ,培育 2 8天时的土壤硝化势与土壤pH值存在着极显著的正相关 ,r =0 75 0 ,土壤剖面各层土壤有机质含量与土壤硝化势也呈正相关 ,但统计没有达到极显著。说明土壤 pH和土壤有机质含量是影响硝化作用的主要因素。同时对 3种土壤上氮肥通过淋洗和反硝化损失的可能性进行了推测 相似文献
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低丘侵蚀红壤复垦后土壤微生物特征研究 总被引：18，自引：7，他引：18
侵蚀红壤复垦培肥后 ,随着地面覆盖度的增加 ,土壤结构、土壤通气性、土壤养分状况得到改善 ,各侵蚀观测小区的年径流量、侵蚀模数、土壤流失量急剧降低 ,土壤微生物量、土壤呼吸强度、土壤酶活性均有较大幅度的提高 ,并且其在各小区的分布趋势与土壤养分和土壤水稳性团聚体的分布趋势相一致 ,说明侵蚀红壤经耕作培肥后 ,土壤有机残体的分解强度和腐殖质的合成过程得到加强 ,土壤肥力处于不断的恢复和提高过程当中 ,从土壤微生物和土壤酶活性增强的幅度来看 ,林地要优于草地 ,在林地中阔叶林优于混交林优于针叶林 (杉木林 ) ,而且随着复垦年限增加 ,土壤培肥效果更加显著 相似文献
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Physical and chemical soil degradation hinder the introduction of mixed cropping systems on former tea lands in the Central Highlands of Sri Lanka. For instance on two typical soil catenas soil properties such as texture, pH, acidity parameters, pedogenic oxides and available plant nutrients indicating fertility are presented. Obviously Al3+ occupies a larger part of the exchange complex and accounts for more soil acidity than H+. Al toxicity is hence a major restricting factor for plant growth in the area. The investigated data also permit an evaluation of soil erodibility and a soil fertility assessment according to the Fertility Capability Classification System (Sanchez et al., 1982). Agricultural measures to reduce soil acidity and cover the lime requirements of the soils are advised. Additional soil conservation measures should diminish soil erosion in order to improve the sustainability of the cropping systems. 相似文献
13.
间伐对杉木林土壤CO2通量的影响 总被引：1，自引：0，他引：1
Forest management is expected to influence soil CO2 efflux (FCO2) as a result of changes in microenvironmental conditions, soil microclimate, and root dynamics. Soil FCO2 rate was measured during the growing season of 2006 in both thinning and non-thinning locations within stands ranging from 0 to 8 years after the most recent thinning in Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations in Huitong Ecosystem Research Station, Hunan, China. Soil temperature and moisture were also measured to examine relationships between FCO2 and soil properties. Forest thinning resulted in huge changes in FCO2 that varied with time since cutting. Immediately following harvest (year 0) FCO2 in thinning area increased by about 30%, declined to 20%-27% below pre-cutting levels during years 4-6, and recovered to pre-cutting levels at 8 years post-cutting. A similar temporal pattern, but with smaller changes, was found in non-thinning locations. The initial increase in FCO2 could be attributed to a combination of root decay, soil disturbance, and increased soil temperature in gaps, while the subsequent decrease and recovery to the death and gradual regrowth of active roots. Strong effects of soil temperature and soil water content on FCO2 were found. Forest thinning mainly influenced FCO2 through changes in tree root respiration, and the net result was a decrease in integrated FCO2 flux through the entire felling cycle. 相似文献
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为评价退耕还林（草）工程的成效及认识下垫面改变对土壤水文过程的影响,采用圆盘入渗仪以4．6、8年退耕地为对象,长芒草草地为对照在黄土丘陵区分层（表层、20cm、40cm）研究退耕地土壤水分入渗特征,并探讨其影响因素。结果表明：1）较短年限退耕地表层土壤入渗能力较天然草地差,而下层入渗能力较天然草地强;2）退耕地下层的初始入渗速率是表层的1．2—1．4倍,稳定入渗率是表层的1．9—2．8倍,饱和导水率是表层的1．9—3．0倍;3）随着退耕年限增加,表层土壤入渗能力下降,而下层入渗能力增强;4）土壤结皮阻碍退耕地表层土壤的入渗。 相似文献
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[目的] 对甘肃盐池湾国家级自然保护区内沼泽湿地土壤的理化性质进行了研究,以期揭示保护区内沼泽湿地土壤特性以及湿地土壤在湿地中的作用,为保护区的湿地保护提供参考。[方法] 在保护区内选择6处典型的沼泽湿地,采用随机法对土壤进行分层取样。根据国家标准对各沼泽湿地土壤的孔性特征、水分特征和养分特征进行了测定。[结果] ①随着土层深度的增加,各沼泽湿地土壤容重逐渐增大,土壤孔隙逐渐减小,土壤通气度逐渐减小。榆林河水脑和大德尔吉湿地土壤的各项孔性指标的测定结果均优于其他各沼泽湿地。②随着土层深度的增加,各沼泽湿地土壤水分特征指标均逐渐下降。榆林河水脑和大德尔吉湿地土壤的各项水分特征指标的测定结果均优于其他各沼泽湿地。③随着土层深度的增加,各沼泽湿地土壤养分含量均呈现下降趋势。榆林河水脑沼泽湿地土壤养分含量较高,野马大泉沼泽湿地土壤养分含量最低,其余4处沼泽湿地土壤养分条件相差不大。[结论] 随着土层深度的增加,保护区内各沼泽湿地土壤逐渐变得紧实,土壤孔隙逐渐减小,水分条件逐渐下降,土壤养分含量逐渐降低。其中,榆林河水脑和大德尔吉湿地土壤的土质疏松,通气性较好,并且有着较为优越的水分条件,具有较强的贮蓄水分和涵养水源的能力。而野马大泉湿地能够快速容纳降水并及时下渗,可有效调节径流。榆林河水脑沼泽湿地土壤养分条件最好,而野马大泉沼泽湿地土壤养分条件最差。保护区沼泽湿地土壤环境整体呈碱性。 相似文献
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针对黄土丘陵半干旱区枣林地土壤干化缺水严重的现象,利用2012—2015年土壤水分、温度等实测数据,分析枣林土壤水分损失的运动规律及其机理。结果表明:休眠期是枣林地土壤水分损失十分严重的阶段,0—200cm土层土壤水分损失量达到85.64~92.34mm,大约是同期降雨量的2倍。蒸发是休眠期土壤水分损失的主体。在垂直剖面上,休眠期土壤水分损失自上而下呈现减少趋势,土壤水分由地下向上运移,最终在近地表以气态水形式散失到大气。土壤气态水运动的活跃层在0—11cm土层间,最大深度为540cm。受温度、相对湿度等因素的影响,土壤气态水通量随土壤深度增加而减少。 相似文献
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Dan HUANG Xinyu ZHU Baile XU Yan HE Mingkui ZHANG Fei LIU Zhenghua LIAN Randy A. DAHLGREN Philip C. BROOKES Jianming XU 《土壤圈》2021,31(5):659-669
Systematic studies on the genesis, properties, and distribution of natural nanoparticles(NNPs) in soil remain scarce. This study examined a soil chronosequence of continuous paddy field land use for periods ranging from 0 to 1 000 years to determine how NNPs in soil changed at the early stages of soil genesis in eastern China. Soil samples were collected from coastal reclaimed paddy fields that were cultivated for 0, 50, 100, 300, 700, and 1 000 years.Natural nanoparticles were isolated and characterized along with bulk soil samples( 2-mm fraction) for selected physical and chemical properties. The NNP content increased with increasing soil cultivation age at 60 g m-2 year-1, which was related to decreasing soil electrical conductivity(172–1 297 μS cm-1) and NNP zeta potentials(from-22 to-36 m V) with increasing soil cultivation age. Changes in several NNP properties, such as pedogenic iron oxide and total organic carbon contents, were consistent with those of the bulk soils across the soil chronosequence. Notably, changes in NNP iron oxide content were obvious and illustrated active chemical weathering, pedogenesis, and potential impacts on the microbial community. Redundancy analysis demonstrated that the soil cultivation age was the most important factor affecting NNP properties, contributing 60.7% of the total variation. Cluster and principal component analysis(PCA) revealed splitting of NNP samples into age groups of 50–300 and 700–1 000 years, indicating rapid evolution of NNP properties, after an initial period of desalinization(approximately 50 years). Overall, this study provides new insights into NNP evolution in soil during pedogenesis and predicting their influences on agriculture and ecological risks over millennial-scale rice cultivation. 相似文献
20.
滇中不同植物群落土壤团聚体组成及养分特征 总被引：1，自引：0，他引：1
采用野外调查和室内分析相结合的方法,对滇中富源县境内华山松-栓皮栎混交林、旱冬瓜林、杨梅灌丛、云南松林、撂荒地5类群落类型的团聚体粒径组成及养分特征进行研究。结果表明,团聚体含量随着粒径（〉5 mm,5～3 mm,3～1 mm,1～0.5 mm,0.5～0.25 mm,〈0.25 mm）的增大及土层（0-10 cm,10-20 cm）的加深而逐渐增多;团聚体的养分含量也呈现一定差异,有机碳、全氮、全钾和水解氮含量随粒径的减小而增多;速效钾含量则随着粒径的减小先增后减。分析团聚体养分的碳、氮比值（C/N）,得知撂荒地〉云南松林〉华山松-栓皮栎混交林〉杨梅灌丛〉旱冬瓜林,揭示C/N越小越有利于碳、氮等养分的循环与流动的规律。 相似文献