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1.
为研究中国土壤系统分类(CST)体系下均腐土不同亚纲土壤细菌群落结构的多样性，以 4个干润均腐土[富牧西系(DFm)、春雷南系(DCl)、保国系(DBg)、明水系(DMs)]和 4个湿润均腐土[大西江系(MDx)、新发北系(MXf)、卫星农场系(MWx)、裴德系(MPd)]的腐殖质层(Ah层)为研究对象，采用高通量测序技术研究细菌群落多样性，分析细菌群落结构与环境因子间的关系，以探讨影响均腐土不同亚纲群落结构的主要环境因子。结果表明:均腐土 8个土系样品共获得 1 674 634条基因序列，Shannon指数和 Chao1指数表现为:干润均腐土 >湿润均腐土。均腐土 8个土系细菌群落主要包括 10个门类，其中变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)为富牧西系、春雷南系、保国系、大西江系、新发北系、卫星农场系、裴德系优势菌门，明水系以绿湾菌门(Chloroflexi)、变形菌门(Proteobacteria)、放线菌门(Actinobacteria)为优势菌门；属水平上，均腐土各土系的群落差异较大。样品热图分析将 8个土系细菌群落聚为 2类，其中干润均腐土聚为一类，湿润均腐土聚为一类。pH、交换性 Ca、CEC、交换性 Mg、SOC和 TP是影响均腐土细菌群落结构发生变化的主要因子( P<0.05)。此外，RDA分析发现，土壤 pH为影响均腐土细菌群落结构的主导因子，而 pH、交换性 Ca、CEC为驱动干润均腐土细菌群落结构发生变化的主要影响因素，交换性 Mg、SOC、TP为驱动湿润均腐土细菌群落发生变化的主要影响因素。 相似文献
2.
为了解岷江上游杂谷脑河谷的土壤发生特征及类型归属，以位于四川阿坝藏族羌族自治州理县杂谷脑河谷的8个典型土壤剖面为研究对象，通过野外成土因素调查与土壤形态特征观测及室内土壤物理、化学性质分析，依据《中国土壤系统分类检索(第三版)》(简称系统分类)与《中国土壤(1998)》(简称发生分类)鉴定其类型。研究表明，8个剖面均为温性土壤温度状况、半干润土壤水分状况；土壤色调为7.5YR和10YR，部分剖面表层明度和彩度均低于3.5，达到暗沃表层的颜色要求；土壤颗粒组成以粉粒含量最高、砂粒次之、黏粒最低，质地为壤土或粉质壤土；土壤结构主要为亚角块状，部分剖面表层为团粒结构；部分剖面中具有腐殖质、黏粒胶膜及假菌丝体等新生体，形成黏化层和钙积层；均具石灰性，主要为碱性到强碱性反应；有机碳含量范围1.64 ~ 61.45 g/kg，部分剖面含量至上而下逐渐降低，具有均腐质特性；游离铁含量为10.78 ~ 19.57 g/kg，个别剖面B层均在14 g/kg以上，具有铁质特性；有效磷含量为1.2 ~ 43.1 mg/kg，个别符合肥熟表层和磷质耕作淀积层的有效磷含量要求。供试土壤在中国土壤系统分类中归属于人为土、均腐土、淋溶土和雏形土4个土纲的4个亚纲、7个土类和8个亚类，在中国土壤发生分类中属于半淋溶土纲下褐土土类的燥褐土亚类(对应于系统分类的石灰肥熟旱耕人为土、普通简育干润雏形土和普通暗沃干润雏形土3个亚类)及石灰性褐土亚类(对应于系统分类的普通暗厚干润均腐土、普通简育干润淋溶土、钙积暗厚干润均腐土、普通钙积干润淋溶土和普通铁质干润淋溶土5个亚类)。中国土壤系统分类具有更强的土壤类型区分能力。 相似文献
3.
河南开封土壤养分变化特征及其持续利用途径研究 总被引：6，自引：0，他引：6
通过 1 984～ 1 998年河南开封不同土壤耕层有机质与氮磷钾养分分析 ,论述了不同农业利用方式和农田管理措施下不同土壤耕层养分的时空变化特征和硝态氮累积特性 .由于“重氮磷 ,轻有机肥 ,忽视钾素补给” ,土壤养分变化的总趋势以下降 ,钾素耗竭性明显 .土壤养分空间变化较为复杂 ,但不同土壤间耕层养分为普通淡色潮湿雏形土 >底锈干润雏形土 >石灰淡色潮湿雏形土 >灌淤旱耕人为土 >简育干润雏形土 >干润砂质新成土 .硝态氮累积表现为由上至下递减或由上至下递增和相对积累于土体某一深度 .最后研究提出了土壤持续利用的有效技术途径 . 相似文献
4.
三峡库区秭归县土壤退化综合评价 总被引：1，自引：0，他引：1
建立了土壤退化评价指标及其评价标准,并对三峡库区秭归县的土壤退化强度、类型与空间变化 进行了评价与分析。结果表明,秭归县土壤退化中紫色土、石灰土、黄棕壤和黄壤的退化较为严重。林荒地比耕地土壤退化严重。耕地中旱地比水田退化严重。秭归县土壤退化类型以薄层化、粗骨化、旱化和养分贫瘠化为主,其中养分贫瘠化又以缺K和缺P趋势明显。土壤退化因人们对土壤利用方式和强度的差异而存在着空间变异,秭归县位于长江两岸河谷地带的一些乡镇土壤养分退化较为严重,而远离此的高山区地带的一些乡镇土壤退化较轻。 相似文献
5.
为全面了解宁夏山地土壤的发育特性及其系统分类归属,基于宁夏土系调查项目挖掘的典型剖面,选取10个发育在宁夏贺兰山山地(剖面编号为3、11、13、14和108)和六盘山山地(剖面编号为73、82、119、120和121)的土壤作为研究对象,结合剖面形态特征和理化性质,尝试对山地土壤的发育特征和系统分类归属进行研究。结果表明:(1)发育在宁夏的10个山地土壤高级单元归属为新成土、雏形土、淋溶土和均腐土等4个土纲,正常新成土、干润雏形土、湿润雏形土、冷凉淋溶土、湿润均腐土等5个亚纲,干旱正常新成土、简育干润雏形土、暗沃干润雏形土、冷凉湿润雏形土、简育冷凉淋溶土、斑纹湿润均腐土等6个土类,石灰干旱正常新成土、普通简育干润雏形土、普通暗沃干润雏形土、暗沃冷凉湿润雏形土、普通简育冷凉淋溶土、斑纹简育湿润均腐土等6个亚类,续分为10个土族,包括粗骨砂质硅质混合型温性—石灰干旱正常新成土,粗骨砂质长石型温性—石灰干旱正常新成土,壤质长石混合型石灰性冷性—普通简育冷凉淋溶土,砂质硅质混合型非酸性冷性—斑纹简育湿润均腐土等,10个供试剖面在土族完全分异,因而续分为10个土系,包括葡萄泉系、一堆系、滚钟口系、六盘山公园系、绿塬腰系等10个土系。(2)海拔对宁夏山地土壤的发育特征有着明显影响,表现为随海拔升高:腐殖质积累过程逐渐明显、土体淋溶过程加剧、土体石灰反应逐渐减弱直至消失;土壤水分条件逐渐改善,处于高海拔位置的山地土壤土体底部有弱氧化还原反应发生,形成铁子和铁锰胶膜;土壤pH逐渐减小,土壤酸碱性发生一定的变化。(3)受成土环境和成土因素的作用,土壤发育规律在诊断特征上的反映为随海拔高度的抬升呈现一定的垂直分异规律,其中诊断表层由淡薄表层演变为暗沃表层;土壤水分状况经干旱/半干润土壤水分状况向湿润土壤水分状况演化;土壤温度状况由温性土壤温度状况变为冷性状况。 相似文献
6.
金沙江干热河谷植被恢复的主要障碍是土壤干旱和以有机质为主的养分缺乏,由此造成人工植被成活率低或生长不良。针对这一因子,借鉴国内外干旱地区微区集水技术经验,结合金沙江干热河谷退化山地年均降雨600mm左右,地方乡土草黄茅(Heteropogoncontortus)人为目的干预下生长良好的实际,设计了山地径流塘-草网络技术。试验研究表明:径流塘-草网络技术具有固土稳水功能,可增强乔木树微区环境土壤抗蚀性能,改善以有机质为主的养分条件及树根区的土壤水分条件,致使研究区内的乔木经济树种酸角(Tamarindusindica)及黄茅生长均超过对照;该技术操作简单,成本低,可在山地退化环境植树种草,发展经济林果中应用。 相似文献
7.
三峡库区秭归县土壤退化综合评价 总被引：5，自引：0，他引：5
建立了土壤退化评价指标及其评价标准,并对三峡库区秭归县的土壤退化强度、类型与空间变化进行了评价与分析。结果表明,秭归县土壤退化中紫色土、石灰土、黄棕壤和黄壤的退化较为严重。林荒地比耕地土壤退化严重。耕地中早地比水田退化严重。秭归县土壤退化类型以薄层化、粗骨化、旱化和养分贫瘠化为主,其中养分贫瘠化又以缺Ｋ和缺Ｐ趋势明显,土壤退化因人们对土壤利用方式和强度的差异而存在着空间变异,秭归县位于长江两岸河谷 相似文献
8.
降雨侵蚀对退化草地土壤养分含量的影响 总被引：4，自引：2，他引：2
为了阐明高寒草甸降雨侵蚀对退化草地土壤养分的影响,以黄河源区退化草地为研究对象,通过野外模拟降雨试验和室内测试,对退化草地土壤养分流失规律进行了分析,这对于揭示高寒草甸草地退化机理和三江源生态环境保护具有重要意义。结果表明:草地退化区土壤养分含量随土层深度的增加而递减,其中40cm范围内的递减幅度较明显;同等条件下坡度为10°的重度退化区土壤养分含量比中度退化区和轻度退化区分别降低了4.2%~49.9%和14.9%~79.4%,而坡度为20°和30°的退化区表层土壤总养分含量均小于10°退化区,且草地退化越严重,则表层土壤略呈弱碱性。与10°退化区相比较,20°和30°的重度退化区养分指标分别降低了5.6%~18.3%和12.2%~44.7%;坡面土壤养分流失主要集中在降雨开始后的30min内,其流失幅度达24.6%~66.4%,其中腐殖质的流失最大,其次为碱解氮、有机质、全氮、速效钾和速效磷,全磷、速效磷和全钾的变化幅度相对较小。降雨侵蚀作用下高寒草甸退化草地的养分流失量比黄土区及人工种植区均大,反映了高寒草地区养分流失是草地退化的原因之一。 相似文献
9.
甘肃农田土壤氮磷钾养分变化特征 总被引：12，自引：3，他引：12
自1983年全国第二次土壤普查以来,由于经过多年的地力培肥,农田土壤养分发生了变化。1998年土壤养分调查结果揭示了甘肃省不同地域的主要耕种土类及耕地类型的土壤氮磷钾养分变化特征,为今后土壤养分资源的综合评价和科学施肥管理提供了基础资料。 相似文献
10.
利用相关分析及土壤退化指数,对比研究了古尔班通古特沙漠与奇台县绿洲交错带荒地、盐碱地、小麦地土壤的养分含量、指数的特征、变化规律和退化程度。结果表明:（1）土壤有机质与表层全氮呈相关性较高的正相关,与碱解氮相关性差。（2）土壤表层速效养分含量下降快于下层。（3）随耕种时间的延长,小麦地土壤养分的全氮、全磷、全钾含量变化较小,而速效成分均大幅度的下降。其中,速效钾下降速度最快,达-38.18 mg/（kg·a）,碱解氮其次,为-14.875 mg/（kg·a）;速效磷仅为-4.486 mg/（kg·a）。（4）未耕地的土壤养分退化指数（SNDI）为-11.30%,明显低于耕种的小麦地。（5）小麦地的年均土壤养分退化指数在最初的3年里为4.317%,随后的2年（5年）是6.485%,而后5年（10年仅为0.788%,即早期退化速度快,随着耕作年限的增加（> 5年）,土壤退化速度迅速减缓。 相似文献
11.
为了探讨气化渣对毛乌素沙漠风沙土的改良效果,利用气化渣作为一种风沙土改良材料,与风沙土按不同掺入量混合,通过对土壤粒径组成、保水性能以及土壤水分特征曲线的变化情况分析,探讨了气化渣对风沙土土壤水分物理性质的影响。结果表明:添加气化渣使风沙土的粒径组成得到明显改善,砂粒含量降低5.89%～35.8%,黏粒、粉粒含量分别提高0.89%～2.92%,7.94%～32.88%,风沙土土壤容重显著降低(p<0.05),降低幅度为7.75%～55.5%; 风沙土土壤质地也由砂土转向砂质壤土,保水性能也随之呈现上升的趋势,显著影响了土壤饱和含水量、毛管持水量和田间持水量(p<0.05),增长幅度分别为13.53%～158.93%,7.12%～126.95%,23.19%～252.47%; Van Genuchten模型可以很好地拟合气化渣添加后风沙土的土壤水分特征曲线,表明气化渣的添加明显提高了土壤保水性,并且风沙土土壤保水性能的主成分分析结果表明气化渣添加量越高土壤保水性提高越明显。由此可以得出,水煤浆气化渣能够有效地改善风沙土的水分物理性质,显著提高风沙土的保水性能,对风沙土改良效果明显。 相似文献
12.
土壤颗粒的分形特征及其应用 总被引：110，自引：4，他引：110
本文应用土壤颗粒的质量分布原理来描述土壤颗粒的分形特征。通过对10种土壤颗粒的机械组成进行分析,分别计算出它们的分形维数（D=2.489～2.896）,并分析了其与土壤质地之间的关系。同时对土壤颗粒分形维数与所对应土壤的幂函数型水分特征曲线的拟合分形维数进行比较分析,建立了二者之间的相关关系。结果表明:分形维数的大小反映了土壤质地中粘粒、粉粒和砂粒含量的变化,随粘粒含量的增多分形维数增大,随砂粒含量的增多分形维数减小;同时土壤颗粒分形维数与所对应的水分特征曲线的拟合分形维数呈现出良好的一致性,因而对所研究的土壤而言,可应用土壤颗粒的质量分形维数结合幂函数模型来估算土壤水分特性曲线。 相似文献
13.
In contrast to modern soil‐profile characterization, alternative soil classifications, such as the German soil‐quality assessment (Bodenschätzung), bear a lower degree of scientific quality. However, despite originally created to determine the tax value of arable land and grassland, its high spatial resolution and complete areal coverage makes soil‐quality assessment a valuable tool. To assess its performance in a mountainous setting soil‐layer data of 60 soil pits, recorded in Bavaria (SE Germany) in the course of the soil‐quality assessment, were translated into German soil‐science terminology using the translation program NIBIS®. With regard to soil type and texture the translation was checked using pinpoint field validation based on soil‐science terminology. 57% of soil types and 61% of texture were correctly translated by NIBIS®. To obtain information about probable parameters that can explain the different results readily available parameters such as elapsed time between soil‐quality assessment and validation, altitude, slope, aspect, horizon thickness, lower edge of horizon, as well as weathering surface and silicate‐weathering rate derived from geological maps were used. Differences in topsoil texture were somewhat related to petrographic parameters, those of the lower subsoil showed a weak dependence to topographic parameters. The NIBIS® translation overrated the silt content to the expense of sand. Clay was the best‐matched texture class. The shift towards silty texture classes was the dominant factor for the differences of texture‐related values of the available water capacity and hydraulic conductivity. Both parameters as derived from the NIBIS® translation on the one and from field validation on the other hand were used to evaluate the water‐retention capacity of individual soil profiles. Despite differing input data the soils' water‐retention capacity was rated identical. Thus, a certain degree of disagreement between the texture data obtained from NIBIS® translation and from field validation is tolerable, if the eventual soil‐function evaluation is based on wide classes of texture or of secondary parameters derived from texture. 相似文献
14.
Landscape-scale soil quality change under different farming systems of a tropical farm in Hainan, China 总被引：1，自引：0，他引：1
Abstract. The impact of different tropical farming systems on soil quality was examined using a systematic sampling strategy. Total organic C, pH, extractable P, exchangeable K, bulk density, water stable aggregates, microbial biomass C, cation exchange capacity, soil depth, and clay content were determined. An assessment framework, including a minimum data set, linear scoring functions and weighted additive indices, was used to evaluate the soil quality of a tropical farm growing various crops in Hainan, China. Soil quality was evaluated according to four functions: water availability, nutrient availability, rooting suitability, and erosion resistance. Our results showed that soils were intrinsically lacking in nutrients and vulnerable to degradation, and that these problems were exacerbated by inappropriate management. There was strong evidence that long-term rubber farming caused soil acidification, soil compaction, and depletion of organic matter and nutrients. By contrast, conservation practices in coffee plantations protected or improved organic matter concentration and soil structure, resulting in higher soil quality indices. 相似文献
15.
土壤水分特征曲线的分形模拟 总被引：17，自引：0，他引：17
Many empirical models have been developed to describe the soil water retention curve （SWRC）. In this study, a fractal model for SWRC was derived with a specially constructed Menger sponge to describe the fractal scaling behavior of soil; relationships were established among the fractal dimension of SWRC, the fractal dimension of soil mass, and soil texture; and the model was used to estimate SWRC with the estimated results being compared to experimental data for verification. The derived fractal model was in a power-law form, similar to the Brooks-Corey and Campbell empirical functions. Experimental data of particle size distribution （PSD）, texture, and soil water retention for 10 soils collected at different places in China were used to estimate the fractal dimension of SWRC and the mass fractal dimension. The fractal dimension of SWRC and the mass fractal dimension were linearly related. Also, both of the fractal dimensions were dependent on soil texture, i.e., clay and sand contents. Expressions were proposed to quantify the relationships. Based on the relationships, four methods were used to determine the fractal dimension of SWRC and the model was applied to estimate soil water content at a wide range of tension values. The estimated results compared well with the measured data having relative errors less than 10% for over 60% of the measurements. Thus, this model, estimating the fractal dimension using soil textural data, offered an alternative for predicting SWRC. 相似文献
16.
Soil texture is an important factor governing a range of physical properties and processes in soil. The clay and fine fractions of soil are particularly important in controlling soil water retention, hydraulic properties, water flow and transport. Modern soil texture analysis techniques (x‐ray attenuation, laser diffraction and particle counting) are very laborious with expensive instrumentation. Chilled‐mirror dewpoint potentiameters allows for the rapid measurement of the permanent wilting point (PWP) of soil. As the PWP is strongly dictated by soil texture, we tested the applicability of PWP measured by a dewpoint potentiameter in predicting the clay, silt and sand content of humid tropical soils. The clay, silt, and sand content, organic matter and PWP were determined for 21 soils. Three regression models were developed to estimate the fine fractions and validated using independent soil data. While the first model showed reasonable accuracy (RMSE 16.4%; MAE 13.5%) in estimating the clay, incorporating the organic matter into the equation improved the predictions of the second model (RMSE 17.3%; MAE 10.9%). When used on all soil data, the accuracy of the third model in predicting the fine fraction was poor (RMSE 31.9%; MAE 24.5%). However, for soils with silt content greater than 30%, the model prediction was quite accurate (RMSE 7–12%; MAE 7–9%). The models were used to estimate the sand content and soil textures of soils, which proved relatively accurate. The dewpoint potentiometer can serve a dual purpose of rapidly estimating the PWP and the clay, fine fraction, and soil texture of soils in a cost efficient way. 相似文献
17.
用压力膜法对黄泛平原不同质地潮土的持水特性进行了研究.结果指出,土壤的持水性、孔径分布和水容量都与土壤质地有密切关系.在高吸力情况下,土壤的持水性随土壤质地变粘而增强.土壤孔径分布与土壤质地的关系是:重力水孔隙随土壤质地变粘而减小;迟效水孔隙和无效水孔隙随质地变粘而增加;而易效水孔隙偏粘的土壤有减小的趋势.土壤水容量也受土壤质地的影响,重力水水容量随质地变粘而增加,易效水水容量是壤土高于砂性土和粘性大,而迟效水水容量则是轻粘土高于其它质地的土壤. 相似文献
18.
固体废弃物修复荒漠化土壤的研究——以包头地区为例 总被引：19，自引：1，他引：19
本文在内蒙古包头市北梁区荒漠化土壤的质地和养分元素含量分析的基础上,与包头市大量堆积的、严重威胁环境的三种固体废弃物(粉煤灰、水库淤积物和污水沉淀物)进行了对比研究。结果表明:该三种废弃物具有细粒、富含植物生长所必需之养分元素的特点。以该区荒漠化土壤作基本土壤,三种废弃物作土壤添加剂进行了玉米、沙棘树和草坪草的种植实验,结果显示:(1)三种废弃物添加到荒漠化土壤中,能够显著增加土壤的养分含量。(2)荒漠化土壤被改造成为近轻壤土的砂壤土或轻壤土。(3)改良后的土壤能够显著增加土壤的生物生产量。 相似文献
19.
S. M. Abubakar 《Land Degradation \u0026amp; Development》1997,8(4):311-323
Lack of baseline data on soil fertility status for most semiarid areas to a very large extent hampers the success of land degradation monitoring. However, this can be overcome by adopting an inferential approach which presupposes that soils of an area of uniform geologic, geomorphic and climatic characteristics differ mainly because of the uses to which they are put. On this basis, soil conditions of a long-standing vegetation community can be used to assess the extent of soil changes resulting from land-use practices, provided that both the vegetation community and the land-use plots are located in an area having the uniform environmental parameters noted above. This approach was adopted in the Kabomo area of Nigeria, a typical semiarid tropical ecosystem, to monitor the extent of soil degradation resulting from 20 years (1972–92) of arable farming, livestock ranching and legume grass farming. Using a systematic sampling procedure, topsoil (0–15 cm) and subsoil (20–30 cm) samples were collected from both the long-standing vegetation community plot (over 80 years old) which was chosen to serve as the control, and the three land-use plots. The collected samples were then analysed for texture, bulk density, water content, water stable aggregates greater than 0·50 mm, organic matter, pH, cation exchange capacity (CEC), total nitrogen, available phosphorus and exchangeable bases. The mean value of every property for each plot was then divided by the mean value of the same property for the control plot in order to assess the extent of change (i.e. extent of degradation) in the property. The Student's t-test was then used to assess the significance of such a change. The results obtained revealed that, in general, the mean values of the various soil properties, with the exception of sand and bulk density, have declined by between 3 per cent and 72 per cent, and in most cases the declines are statistically significant. Sand and bulk density, on the other hand, show some increases of between 6 per cent and 78 per cent, though only the increase in respect of the sand fractions are statistically significant. Similarly, it was observed that the extent of degradation was much greater under the arable land and least under the livestock ranching plot. The potential causes of these trends were discussed, while suggestions were offered on how best to utilize this approach in carrying out effective monitoring of land resources in the semiarid tropics. © 1997 John Wiley & Sons, Ltd. 相似文献
20.
东北典型黑土区坡耕地涝渍地土壤持水性和导水性研究 总被引：1，自引：0，他引：1
中国东北典型黑土区是我国重要的商品粮生产基地,对我国粮食安全和国民经济的稳定起到举足轻重的作用。作为土壤退化的一种特殊形式,涝渍地严重影响着垦区的农业生产。在东北典型黑土区坡面涝渍地及其周围正常耕地中布设采样点,测定了土壤剖面质地分布情况及土壤水分特征曲线,以揭示东北黑土区坡面涝渍地土壤水分过大的根本原因。结果表明,涝渍地土壤剖面中细质地土壤类型所占比例为90%,质地较粘重。涝渍地土壤具有较高的进气值,水吸力较大,保持在中小孔隙中的水分只有在较大吸力范围内才能缓慢释出,这造成涝渍地土壤具有极强的持水能力,不容易失水,再加上极弱的导水能力,水分饱和但不会被释放。以上这些土壤特性导致了涝渍地土壤长期处于湿度过大的状态。本研究结果可为涝渍地治理提供依据。 相似文献