广西平果县岩溶山地不同植物群落的土壤酶活性

为探讨平果县岩溶山地典型植物群落的土壤酶活性特征,基于调查取样与试验分析,采用相关分析、多重比较以及主成分分析方法,研究了不同植物群落间土壤酶活性的差异,分析了土壤酶活性与土壤化学性质的关系。结果表明:(1)土壤过氧化氢酶、脲酶及蔗糖酶活性的群落间差异达显著水平,显示不同植物群落对土壤酶活性产生一定影响;(2)土壤pH值与过氧化氢酶、脲酶间呈极显著正相关(p0.01),与碱性磷酸酶间呈显著负相关(p0.05);(3)4个酶活性与代表土壤肥力的土壤有机质、全氮、全磷、全钾、碱解氮及速效钾之间具有较强的相关性,但速效磷与4个土壤酶之间的相关性均未达显著水平(p0.05);(4)过氧化氢酶、脲酶及碱性磷酸酶能敏感反映土壤质量的变化,可作为本区域土壤质量评价的指标。     

甘肃省盐碱草地主要植物群落土壤酶活性研究

对甘肃省盐碱地主要植物群落土壤脲酶、过氧化氢酶、碱性磷酸酶、脱氢酶及硝酸还原酶活性的季节动态进行研究。结果表明,5种土壤酶活性季节变化趋势不同,脲酶、过氧化氢酶及碱性磷酸酶活性均在夏季达到最高,硝酸还原酶在秋季最高,脱氢酶在春季最高;不同植物群落土壤酶活性变化趋势不同,脲酶、碱性磷酸酶、过氧化氢酶活性在狗尾草群落(Setaria viridis)具最大活性,硝酸还原酶、脱氢酶活性在芦苇群落(Phragmites australis)均最高,5种酶活性在盐爪爪群落(Kalidium foliatum)均最低;各植物群落的土壤酶活性多表现为随着土壤深度的加深呈递减趋势,在表层0—5cm土层,土壤酶活性最强。对5种酶之间的相关性进行分析,研究发现碱性磷酸酶与脲酶、过氧化氢酶间呈极显著相关,脲酶与过氧化氢酶、硝酸还原酶与脱氢酶间呈显著相关。     

黄河三角洲退化湿地土壤养分、微生物与土壤酶特性及其关系分析

为了揭示黄河三角洲湿地退化与土壤的关系,为湿地生态修复和有效利用湿地资源提供理论依据,对黄河三角洲退化湿地不同演替阶段的土壤酶活性、土壤养分和土壤微生物特性及土壤酶与养分和微生物的关系进行分析。结果表明:随着湿地由白茅群落到光板地的逆向演替,土壤脲酶、蛋白酶活性呈逐渐下降趋势,碱性磷酸酶和过氧化氢酶活性变化规律与其相似;不同演替阶段土壤酶活性表现出差异性,各种酶之间蛋白酶活性最高;土壤养分质量含量基本都随着湿地逆向演替的进行而递减,不同演替阶段土壤养分质量分数差异显著;退化湿地土壤中各种微生物数量存在明显差异性,在土壤微生物群落中,细菌数量所占比例最大,在各类微生物中占绝对优势,其次为放线菌,真菌数量最少;白茅群落阶段细菌和真菌数量最多,柽柳群落阶段放线菌数量最多;土壤酶与土壤养分、土壤微生物存在密切正相关关系;细菌与脲酶和过氧化氢酶有密切关系,真菌与脲酶、过氧化氢酶和碱性磷酸酶都具有显著的相关性。     

河口湿地红树林植被恢复对土壤养分动态的影响

以泉州湾河口人工红树林湿地为研究对象,以光滩为对照,采集0—10,10—20,20—30 cm土层土壤,研究不同红树林恢复(桐花树、秋茄、秋茄-桐花树混交林)对河口湿地土壤pH、有机质及主要养分元素(氮磷钾)的影响。结果表明:不同植被恢复模式下土壤pH和有机质含量呈明显的垂直变化特征,相对于无植被的光滩(恢复前),红树林植被恢复显著降低了土壤pH (P＜0.05),但增加了土壤有机质含量(P＜0.05)。不同红树林恢复模式下,土壤碱解氮、有效磷、速效钾和全钾含量均大致表现为随土层深度的增加而增加,而全磷含量则表现为随深度的增加而降低。相对于恢复前,红树林植被恢复均增加了表层土壤主要养分(氮磷钾)含量,其中,以桐花树—秋茄混交林的影响最为显著(P＜0.05)。综上,不同模式红树林植被恢复对河口湿地土壤理化性质和养分动态具有明显的调节作用,其中,混交林模式通过高效利用地上地下空间,改善土壤结构和质量,增加生物量和养分归还量,显著改善了土壤养分动态,是河口区植被恢复的优选手段。研究结果可为加强河口红树林湿地养分管理、维护湿地系统养分平衡提供科学参考。     

黑土酶活性的剖面分布及其对养分的评价

在黑龙江省内选取9个典型黑土剖面,研究其土壤过氧化氢酶、磷酸酶、脲酶、转化酶、硝酸还原酶活性的剖面分布规律。结果表明：在0-40 cm土层中,黑土5种酶活性都随土壤层次的加深而下降,而在40cm以下的土层中,过氧化氢酶、硝酸还原酶、转化酶活性不再降低,趋于稳定或略有升高,磷酸酶和脲酶活性却急剧降低,甚至没有酶活性;相关分析表明,土壤过氧化氢酶、磷酸酶、脲酶、硝酸还原酶活性和土壤全氮、速效氮、全磷、全钾、全碳含量及C/N显著相关,土壤转化酶活性和土壤全氮、速效氮、全钾、速效钾、全碳含量显著相关,主成分分析结果显示在第一主成分中,土壤磷酸酶、脲酶活性占有较大比例,可以用来作为土壤氮素、全量磷分和全量碳分的指示指标。     

三江平原湿地不同土地利用方式对土壤养分及酶活性的影响

以中国科学院三江平原湿地生态试验站为对象,研究了不同利用方式（湿地草甸、旱田系统、退耕成草、退耕成林）对土壤酶活性分布特征及相关因子的影响。结果表明:土壤利用方式不同,土壤酶活性（转化酶、脲酶、磷酸酶和过氧化氢酶）、有机碳含量和土壤养分含量有较大差异。土壤有机碳、全氮、全钾、速效磷、碱解氮、微生物量碳和氮均呈现出一致的变化规律,依次表现为湿地草甸 > 退耕草地 > 退耕林地 > 旱田系统,也即由湿地草甸退化过程中,土壤养分含量逐渐降低,其中不同土地利用方式下土壤全磷含量差异不显著（p>0.05）,在湿地的退化过程中,土壤全磷并没有发生显著的变化。与湿地草甸相比,土壤蔗糖酶、脱氢酶、脲酶和酸性磷酸酶活性均显著降低,其活性分别降低了32.69%,36.71%,50.00%,44.28%,由旱田系统恢复为湿地草甸系统后,土壤各种酶活性均显著增加,其中土壤蔗糖酶、脱氢酶、脲酶和酸性磷酸酶活性分别比旱田系统增加了26.68%,31.51%,48.19%,43.84%;表明由湿地草甸开垦为耕地和由耕地恢复为湿地草甸和林地,发生着两种不同的生物学过程,前者为微生物降解过程,而后者则为微生物累积过程。相关性分析表明SOC,TN和SMBC对土壤蔗糖酶、脱氢酶、脲酶和酸性磷酸酶活性的贡献为正,对土壤酶活性起到主导作用。主成分分析表明影响土壤酶活性最主要的因子为SOC,TN和SMBC。     

长期定位施肥对土壤酶活性的影响及其调控土壤肥力的作用

为探讨长期施肥条件下土壤酶活性及其与土壤肥力的关系,对褐潮土肥料定位试验田第12年的土壤酶以及土壤养分因子进行了测定和分析。结果表明,NPK与有机肥长期配合施用能明显提高土壤有机质含量,全氮、全磷及速效氮、磷、钾含量,增强土壤转化酶、磷酸酶和脲酶的活性。玉米秸秆有利于提高土壤转化酶活性,而有机肥则主要提高土壤脲酶和磷酸酶活性;采用轮作方式比连作能更好地培肥土壤。土壤酶活性与土壤肥力之间具有很好的相关性,其中,磷酸酶、脲酶、转化酶活性与有机质、全磷、速效磷含量呈显著正相关;磷酸酶与碱解氮、速效钾,脲酶与速效钾,转化酶与碱解氮均呈显著相关。长期施肥不能增强土壤中过氧化氢酶活性,过氧化氢酶与土壤养分之间无明显相关。     

长期施肥对薄层黑土酶活性及土壤肥力的影响

利用29年的长期定位试验,对不同的施肥方式下薄层黑土酶活性及肥力进行了研究,探讨长期施肥对土壤酶活性及与土壤肥力的影响。结果表明,化肥与有机肥配合施用能明显提高土壤有机质、全氮、全磷、碱解氮、有效磷含量,增强土壤脲酶、磷酸酶、转化酶、过氧化氢酶、脱氢酶活性。相关分析结果显示,土壤脲酶、磷酸酶、转化酶、过氧化氢酶、脱氢酶活性与有机质、全氮、全磷、有效磷、碱解氮呈显著正相关。土壤脲酶、磷酸酶、转化酶、过氧化氢酶、脱氢酶综合活性可以反映长期施肥后薄层黑土质量的变化趋势。     

长期施用有机肥对草甸碱土土壤酶活性及养分特征的影响

依托东北农业大学盐碱土改良长期定位试验站,以松嫩平原草甸碱土为研究对象,探讨不同年限有机培肥措施下草甸碱土酶活性变化趋势、有机质和养分提升状况及其相互关系。结果表明:长期施用有机肥,草甸碱土脲酶、蔗糖酶、磷酸酶活性含量均显著提高,长期施用有机肥对过氧化氢酶活性影响较小。草甸碱土有机质、全氮、全磷及碱解氮、有效磷含量均显著提高,土壤pH值显著降低。施用有机肥5年后,草甸碱土的改良效果显著。经相关分析,土壤脲酶、蔗糖酶、磷酸酶与土壤有机质和养分间呈显著或极显著正相关,过氧化氢酶则无显著相关性。     

三江平原不同类型湿地土壤酶活性及其与营养环境的关系

对三江平原3种典型湿地(毛苔草湿地、小叶章湿地、岛状林湿地)的土壤酶活性、土壤养分进行了研究,探讨了不同湿地土壤酶与土壤养分及酶活性间的相关性。结果表明:不同湿地土壤酶活性和土壤养分含量有较大差异。土壤蔗糖酶、脲酶、过氧化氢酶、淀粉酶活性与土壤有机质、全氮、碱解氮含量变化趋势一致,表现为毛苔草湿地>小叶章湿地>岛状林湿地。酸性磷酸酶活性表现为岛状林湿地>毛苔草湿地>小叶章湿地;纤维素酶活性则表现为毛苔草湿地>岛状林湿地>小叶章湿地。经分析,土壤酶活性和养分密切相关,且酶活性间存在一定的相关关系,其中脲酶、过氧化氢酶、淀粉酶活性与土壤养分相关性最好,呈显著或极显著正相关。并且这3种酶活性之间也呈显著或极显著正相关,因此脲酶、过氧化氢酶、淀粉酶活性可以作为该地区较为理想的湿地营养状况的表征指标。     

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 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.     

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.     

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。     

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。     

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.     

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。     

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.     

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。