黑河上游冰沟流域不同林地土壤理化性质及有机碳和养分的剖面变化规律

在黑河上游的冰沟流域,采用野外采样和室内分析方法研究不同林地土壤理化性质及有机碳和养分的剖面变化规律.结果表明:不论是林地还是草地,土壤容重、物理性砂粒、pH值、CaCO3均随着土层的加深而增大;而孔隙度、团聚体、有机碳、全氮、全磷、CEC均随着土层的加深而降低.林地与草地土壤剖面的容重、物理性砂粒、pH值、CaCO3由小到大变化顺序为林地＜草地;而总孔隙度、团聚体CEC、有机碳、全氮、全磷由大到小变化顺序为林地＞草地.不同林地土壤剖面容重、物理性砂粒、pH值、CaCO3由小到大变化顺序为青海云杉＜高山灌丛林＜祁连圆柏林;而总孔隙度、团聚体CEC、有机碳、全氮、全磷由大到小变化顺序为青海云杉林＞高山灌丛林＞祁连圆柏林.     

祁连山哈溪林区典型植被土壤阳离子交换量和交换性盐基离子的变化特征

选择祁连山东段哈溪林区的高山灌丛林、祁连圆柏林和青海云杉林3种典型植被土壤为研究对象,研究了其0～100 cm土层土壤阳离子交换量(CEC)和交换性盐基离子(K~+、Na~+、Ca~(2+)、Mg~(2+))的垂直分布规律。结果表明,随土层深度增加,高山灌丛林、祁连圆柏林和青海云杉林的土壤CEC值均不断减小,不同植被按其土壤CEC值大小排序为祁连圆柏林>青海云杉林>高山灌丛林;土壤交换性K~+、Na~+、Ca~(2+)、Mg~(2+)含量随土层深度变化规律各不相同,交换性K~+含量不断减小,交换性Na~+、Ca~(2+)、Mg~(2+)含量没有明显的变化规律;不同森林土壤交换性盐基总量(TEB)变化规律各不相同,按其值大小排序为青海云杉林>祁连圆柏林>高山灌丛林;土壤中交换性K~+、Na~+、Ca~(2+)和Mg~(2+)含量占TEB比例大小为Ca~(2+)>Mg~(2+)>Na~+>K~+;不同森林土壤盐基饱和度(BSP)变化规律亦不相同,按其大小排序为青海云杉林>祁连圆柏林>高山灌丛林。     

祁连山北坡主要植被下土壤异质性研究

采用半微量凯氏、氢氧化钠-钼锑抗比色法、CaCO2分子式求法、土壤烘干法、环刀法等进行土壤异质性相关因子调查与分析,结果表明:(1)山地灰褐土、山地淋溶灰褐土、亚高山灌丛草甸土、山地栗钙土的有机质含量分别为11.88%、10.85%、10.73%、1.65%.(2)青海云杉林、高山灌丛林、祁连圆柏林、低山灌丛林、牧坡草地、无林地0-60 cm土壤容重依次减小,而总孔隙度依次增大.     

大青山不同林地类型土壤特性及其水源涵养功能

对内蒙古大青山4种林地类型的土壤特性、凋落物持水量及林地土壤贮水性能进行了研究。结果表明:①林地间土壤容重和孔隙度差异较大,容重大小依次为油松人工林>虎榛子灌丛林>落叶松人工林>白桦山杨天然次生林;总孔隙大小依次为白桦山杨天然次生林>落叶松人工林>虎榛子灌丛林>油松人工林;②林地间凋落物蓄积量和最大持水率差异较大,蓄积量大小依次为落叶松人工林>白桦山杨天然次生林>虎榛子灌丛林>油松人工林;最大持水率大小依次为落叶松人工林>白桦山杨天然次生林>虎榛子灌丛林>油松人工林;③依据林地总贮水量的大小,4种林地水源涵养功能大小依次为白桦山杨天然次生林(3 687.172 t/hm2)>落叶松人工林(3 553.229 t/hm2)>虎榛子灌丛林(3 035.698 t/hm2)>油松人工林(2 796.279 t/hm2)。     

川西亚高山针叶林植物群落演替对土壤性质的影响

研究了川西亚高山针叶林人工重建过程中土壤物理性质,结果表明:随着人工云杉林龄的增加,土壤表层粉粒、粘粒、物理性粘粒、团聚度和结构系数降低,砂粒含量增高,土壤饱和持水量、毛管持水量及总孔隙和毛管孔隙在人工云杉林演替过程中表现出"U"型变化,即人工云杉从幼林向成熟林演替阶段,土壤饱和持水量、毛管持水量及总孔隙和毛管孔隙则减少,在40年生云杉林达最低值之后,随着云杉自疏而有上升的趋势,毛管持水量是决定林地土壤自然含水量的主要因子。为了加速该区域植被恢复和重建过程,建议营造针阔混交林和对人工成熟林和过熟林进行间伐抚育,增加物种多样性,减少水土流失,为植物生长创造良好的土壤物理环境。     

对六盘山主要森林类型涵蓄降水能力的探讨

本文分析了六盘山林区主要森林类型土壤的水文性质、最大贮水能力,探讨了林地涵蓄降水量的最大值,并提出了计算公式,林地土壤涵蓄降水量包括非毛管孔隙的滞蓄量和部分毛管孔隙持水量,且有季节变化。其计算公式为W_T=W_a-W_o+W_c或W_T=W_a-W_o。     

喀斯特地区不同年限退耕草地的持水性能

[目的] 研究不同年限退耕草地持水性能,为喀斯特地区退耕草地持水性能和水土保持提供科学依据。[方法] 选取贵州省安顺市喀斯特地区不同年限退耕草地(5,10,15,20 a)和耕地(对照CK)为研究对象,采用“时空替代法”研究凋落物蓄积量、持水量和拦蓄量以及土壤剖面容重、孔隙度、颗粒组成、含水率及持水量随退耕年限的变化特征。[结果] ①凋落物层蓄积量、最大持水量、最大拦蓄量和有效拦蓄量均表现为:15 a＞20 a＞10 a＞5 a,且凋落物层持水量、吸水速率与浸水时间的关系分别符合对数函数和幂函数。②退耕草地砂粒含量和容重随着退耕年限的延长均呈现出先下降再上升的趋势;粉粒、黏粒、总孔隙度、毛管孔隙度、最大持水量和毛管持水量的变化规律与土壤容重相反。③凋落物层和土壤层的持水总量表现为:10 a＞20 a＞15 a＞5 a＞CK,其中土壤层最大持水量贡献率达到99%以上。[结论] 退耕草地不仅增加了凋落物层的生物积累、拦截降雨作用和持水性能,还在改善土壤结构和孔隙状况的同时,提高了土壤持水性能。退耕草地均在退耕10 a以后逐渐趋于稳定。因此,建议在退耕10 a以后种植落叶树种。     

冀北山地蒙古栎天然林土壤物理性质及水源涵养功能研究

对冀北山地不同坡位的蒙古栎天然林土壤水分物理性质及水源涵养能力进行了初步研究.结果表明,0-40 cm土层土壤容重、非毛管孔隙度、有效持水量均表现为:坡中＞坡下＞坡上,土壤容重在1.0～1.1 g/cm3之间;土壤非毛管孔隙度和有效持水量均值为8.9％和347.6 t/hm2.土壤毛管孔隙度、总孔隙度、毛管持水量和最大持水量均表现为:坡下＞坡中＞坡上,其均值分别是38.5％,47.5％,1 521.50t/hm2和l 869.1 t/hm2.枯落物厚度、蓄积量和最大持水量表现为:坡下＞坡上＞坡中,其均值分别是48.7 cm,23.5 t/hm2和49.3 t/hm2,最大持水率表现为:坡上＞坡中＞坡下,变化范围为219.3％～231.8％.蒙古栎天然林林地蓄水能力表现为:坡下(1 996.0 t/hm2)＞坡中(1 930.0 t/hm2)＞坡上(1 829.3 t/hm2),平均蓄水量为1 918.4 t/hm2.由此可知,蒙古栎天然林蓄水能力受坡位影响较大.     

不同林龄白桦次生林土壤特性及其水源涵养功能

以小兴安岭地区4个林龄的白桦次生林为研究对象,对其土壤特性、土壤贮水性能、凋落物持水量进行研究。结果表明：白桦次生林凋落物的蓄积量、最大持水量均以38 a为最大,70 a相对较低,凋落物蓄积量与最大持水量有显著正相关关系;土壤非毛管孔隙度随林龄变化呈波动性变化,38 a白桦次生林0-30 cm土层非毛管孔隙最大,有利于降水的下渗,而25 a白桦次生林0-30 cm土层非毛管孔隙最小,不利于水分下渗。土壤水源涵养功能大小排序为70 a（3 628.445 t/hm^2）〉56 a（3 524.015 t/hm^2）〉25 a（3 433.626 t/hm^2）〉38 a（3 275.820 t/hm^2）。     

半干旱退化山区不同土地利用方式土壤理化性质的特征研究

通过对半干旱退化山区不同土地利用方式的土壤理化性质的调查研究.得出不同土地利用措施土壤机械成分表现出一定的差异性,在0-40 cm土层,88542整地和人工草地的粗砂粒平均含量高于天然草地;在0-100 cm土层,最大田间持水量:人工林地＞人工草地＞天然草地;毛管持水量:人工草地＞人工林地＞天然草地;土壤总孔隙度:人工林地＞人工草地＞天然草地;毛管孔隙度:人工草地＞人工林地＞天然草地;土壤的透气性:人工林地＞人工草地＞天然草地.在0-100 cm土层:有机质的含量为:人工林地＞天然草地＞人工草地;土壤碱解氮的含量变化为:人工林地＞人工草地＞天然草地;土壤速效磷的含量变化为:人工林地＞人工草地＞天然草地.结果表明,合理的土地利用方式,改善了土壤结构和肥力,增加土壤的通透性,改变土壤水肥气热状况,其中人工造林整地对土壤容重、持水量、土壤养分的促进作用均优于其它利用方式,有利于植被的快速恢复.     

Soil Erodibility and Physicochemical Properties of Collapsing Gully Alluvial Fans in Southern China

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.     

Bodengefüge gegen Verdichtungen schützen – Lösungsansätze für den Schutz landwirtschaftlich genutzter Böden

Protecting soil structure against compaction—proposed solutions to safeguard agricultural soils To safeguard the ecological soil functions and the functions linked to human activities, measures against harmful changes to the soil are required, in line with the precautionary principle. The German Federal Soil Protection Act sets obligations for precaution in agricultural land use and, if harmful changes to the soil are foreseeable, measures for averting a danger. The results of a research project of the Federal Environmental Agency show that it is possible to describe an impairment of the soil structure, using methods of soil analysis. But this as a sole information would not qualify for the identification of harmful changes to the soil in the context of the Soil Protection Act, which requires an assessment of the severity of disruption of soil functions and the respective subject of protection. This would make additional soil investigations on site mandatory. Approaches in agricultural engineering and soil physics have introduced procedures to preserve the soil structure, in accordance with the precautionary principle. But these procedures have different goals and different ranges of application and hence offer partial solutions to safeguard against soil compaction. The assessment model of “trafficability by measuring the rut depth” provides information about the compaction status of the soil under applied conditions for farming gear, without providing detailed information about affected soil layers. The soil‐physical model of classifying soils into “risk classes for harmful soil compaction” focuses on the relationship between topsoil compaction and crop yields. The soil‐physical models “precompression stress” and “loading ratio” provide information for the assessment of subsoil compaction and a prognosis of a possible impairment of the soil structure at the water content of field capacity. It is necessary to validate the individual models with additional regional data about soil structure before a final assessment of the prognoses is made.     

Soil health – What should the doctor order?

The concept of soil health has been extensively reviewed in the scientific literature, but there is only patchy and inconsistent information available to farmers and growers who are concerned about the declining condition of their soils and are looking for appropriate test methods and management interventions to help reverse it. Although there are well‐established laboratory methods for soil chemical analysis, and a range of laboratory and field methods for measuring soil physical properties, only now are methods starting to emerge for soil biological analysis. This study provides an overview of the methods that are currently available commercially (or are close to commercialization) for farmers and growers in the UK. We examine the science underpinning the methods, the value of the information provided and how farmers and advisors can use results from such assessments for informed decision‐making in relation to soil management.     

长期化肥有机替代对黑土颜色及腐殖物质的影响

基于30年长期定位试验,通过测定黑土光谱反射率和不同腐殖质组分含量,探究了不同施肥对黑土土壤腐殖质含量、土壤颜色及二者之间的关系。试验设置5个处理:(1)休耕(Fallow);(2)不施肥处理(CK);(3)单施化肥(NPK);(4)有机肥部分替代化肥(NPKM);(5)秸秆部分替代化肥处理(NPKS)。结果表明:与NPK处理相比,Fallow、NPKS、NPKM分别显著提高49.7%,74.3%,27.0%的土壤有机碳含量(p<0.05)。NPKM处理中胡敏酸(HA)含量最高为3.9 g/kg,随后依次为CK、NPKS、NPK、Fallow。NPKM、NPKS和Fallow处理中土壤富里酸(FA)含量为2.2~2.3 g/kg,显著高于NPK和CK。NPKM处理中胡敏素(HM)含量为18.6 g/kg,显著高于其他处理(p<0.05)。不同处理间土壤光谱反射率由高到低依次为NPK>Fallow、CK>NPKS>NPKM,与CK处理相比,NPK土壤光谱反射率在平均提高6.5%,NPKS和NPKM则分别降低11.1%和15.1%。根据线性相关分析结果,黑土土壤光谱反射率与土壤HAHM均呈显著负相关关系(p<0.01),相关系数(r)分别为-0.858,-0.681。综合上述结果,长期有机物料投入可以显著提高黑土腐殖物质含量,降低黑土光谱反射率,使黑土颜色加深,而长期化肥施入则使黑土光谱反射率提高,出现"褪色"现象,有机粪肥在黑土中对土壤有机质和腐殖质含量的提升效果优于秸秆。     

金沙江干热峡谷中退化的土壤生态系统生物学特征初探

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.     

土壤孔隙结构与土壤微环境和有机碳周转关系的研究进展

土壤结构是土壤功能的基础,不仅影响土壤养分的供应、水分的保持及渗透、气体的交换等过程,还为土壤微生物提供了物理生境,并调控土壤有机碳的周转这一关键过程。土壤的孔隙特征能够直接、真实地反映土壤结构的好坏;用土壤的孔隙特征作为试验指标能更好地反映土壤结构对这些过程的调节作用。在此基础上,将高度异质性的土壤孔隙结构同土壤微环境的变化和土壤有机碳的周转过程进行定量分析,对深入了解土壤结构在土壤生态系统中的功能至关重要。因此,着重从土壤孔隙结构对土壤微环境的影响及其与有机碳的关系两方面展开,剖析土壤孔隙结构调控作用下的土壤微环境响应过程,阐述土壤孔隙结构对土壤有机碳周转产生的直接、间接影响,强调土壤孔隙结构在调节土壤有机碳周转进程中的重要作用,并对土壤孔隙结构在调节土壤有机碳周转、植物残体分解及其与微生物协调作用机制等方面研究提出展望。     

设施栽培下原状土与扰动土水分特性的试验研究

以四川省双流县设施栽培土壤为研究对象,对其原状土与扰动土的土壤水分特征曲线、水分物理性质和比水容量等项目进行了研究。结果表明,扰动土水分特征曲线总体变化趋势与原状土较为一致。在低吸力阶段,相同吸力条件下扰动土含水量高于原状土,在高吸力阶段两者差异较小。扰动土毛管孔隙度、总孔度和凋萎含水量在剖面上的总体变化趋势与原状土较为一致。扰动土不同土层田间持水量和有效水含量差异较小,原状土的田间持水量和有效水含量均随土层加深而减少。在低吸力阶段,相同吸力条件下扰动土比水容量远高于原状土,但随土壤水吸力增加,扰动土比水容量变化趋势逐渐与原状土一致。     

植物苗期根系抗侵蚀特性试验研究——以构树和顶坛花椒为例

植物的固土抗蚀作用大小与其根系密切相关,而根系特征决定了根的固土抗蚀作用的发挥,本文以相同基质下构树和顶坛花椒不同特征的根系为研究对象.通过研究根系特征与土壤抗冲性、抗蚀性、抗拉性、紧实度的关系,结果表明,苗期根系能强化土壤抗冲性,构树苗、顶坛花椒苗根系强化值大小分别为78.01>77.71;根系可提高土壤抗蚀性,其抗蚀性强弱为.构树苗>顶坛花椒苗>对照,构树、顶坛花椒、对照试验的土壤水稳性指数分别为4.36,3.16,1.67;不同树种根系对土壤的固结能力不同,构树苗生长下的土壤抗拉能力为214.92 N,明显大于顶坛花椒苗生长下的土壤154.87 N;土壤紧实度大小为构树苗>顶坛花椒苗.并采用加权综合指数法综合评价了苗期不同特征植物根系的固土能力强弱,得出构树苗综合指数为1.058.而顶坛花椒苗为0.902.即构树苗的固土能力强于顶坛花椒,以期为今后的水土保持工作提供一定的理论依据.     

土壤润湿性受土壤特性及土地使用的影响

Depth distribution of soil wettability and its correlations with vegetation type, soil texture, and pH were investigated under various land use (cropland, grassland, and forestland) and soil management systems. Wettability was evaluated by contact angle with the Wilhelmy plate method. Water repellency was likely to be present under permanently vegetated land, but less common on tilled agricultural land. It was mostly prevalent in the topsoil, especially in coarse-textured soils, and decreased in the subsoil. However, the depth dependency of wettability could not be derived from the investigated wide range of soils. The correlation and multiple regression analysis revealed that the wettability in repellent soils was affected more by soil organic carbon (SOC) than by soil texture and pH, whereas in wettable soils, soil texture and pH were more effective than SOC. Furthermore, the quality of SOC seemed to be more important in determining wettability than its quantity, as proofed by stronger hydrophobicity under coniferous than under deciduous forestland. Soil management had a minor effect on wettability if conventional and conservation tillage or different grazing intensities were considered.     

土壤因子研究综述

介绍了国内外土壤因子的研究方法及研究成果,指出我国目前土壤因子研究中存在的问题,并结合我国土壤因子研究现状,认为继续土壤水蚀机理的研究是今后土壤因子研究的内容之一,同时,随着GIS和RS技术发展,应用GIS和RS技术研究区域土壤因子也将成为潮流。