土壤风蚀过程颗粒释放机理研究

针对目前土壤风蚀中土壤颗粒释放过程机理研究存在的不足,建立了颗粒在土壤表面起动、滚动、起跳的土壤颗粒释放力学模型,同时考虑了太阳辐射及地表温度产生的向上垂向风速对颗粒起动风速的影响,并采用前人的实验结果与本文模型数值计算结果进行了对比分析,证明其模型的合理性。数值结果表明：起动风速随颗粒粒径的增大先减小后增大,其中在0.12~0.14 mm粒径范围内颗粒最容易起动,同时床面温度越高对颗粒的起动风速影响也越明显,同一粒径下床面温度越高起动风速越小。颗粒在床面上的运动不是纯滚动,而是滚动中有滑动。颗粒起跳速度主要分布在0.3~0.65 m/s之间;起跳角度30°~35°之间;颗粒起跳的角速度主要分布在600~1 200 rev/s。土壤颗粒释放微观过程的研究将对改进土壤风蚀输送过程中的宏观监测与预报起到重要作用。     

Carbon fluxes in soil: long-term sequestration in deeper soil horizons

Terrestrial ecosystems represent the second largest carbon reservoir, and the C balance in terrestrial ecosystems can be directly impacted by human activities such as agricultural management practices and land-use changes. This paper focuses on the C-sequestration in soil. Although many studies showed that the concentration of SOC is much higher in the shallow soils (0-30 cm), the deeper horizons represent a much greater mass of soil and represent a huge C-storage pool. The process of preferential retention of more strongly adsorbing components, along with competitive displacement of weakly binding components are the key processes that enhance the movement of organic carbon to deeper soil horizons. DOC represents the most dynamic part of organic carbon in soils, and thus can be used as a timely indicator of the short-term change of C-sequestration. Long-term experiments have demonstrated that higher SOC levels in shallow soils would lead to increased fluxes of DOC to deeper horizons, but more data on a wider range of soils and treatment strategies are needed to fully evaluate the linkages between changes in SOC in shallow soil, vertical fluxes of DOC to deeper soil horizons, and enhanced C-inventories in deeper, slow-turnover SOC pools.     

荒漠草原碳酸盐岩土壤有机碳向无机碳酸盐的转移

通过在内蒙古中西部四子王旗荒漠草原土壤剖面采集土样,拟分析测定土壤有机碳(SOC)含量、土壤无机碳酸盐(SIC)含量和SIC的δ13C值,探讨SOC向SIC的迁移转化过程及其转移量。结果表明:随深度增加,SOC含量逐渐降低而SIC含量依次增大,SOC与SIC含量具有明显的负相关关系。随土层加深,SIC的δ13C值降低,在30 cm深度时相对最低为-8.6‰,而后增大,在深度为60 cm时其值为-5.8‰。说明通过"SOC—CO2—SIC"的微碳循环系统SOC向SIC发生碳的转移。应用碳稳定同位素技术和模型结合SIC的δ13C值对该研究区SIC进行区分,发现30~50 cm土层次生碳酸盐(PC)所占比例为58.5%,50~60 cm土层为44.2%。应用δ13C值对该地区SOC向SIC的转化碳量进行估算,该地区30~60 cm土层每千克土壤中大约固定了SOC分解转化的4.97~5.9 g CO2。     

土壤碳通量--深土层的长期吸收

1IntroductionEarth'satmosphereisbeingsignificantlyalteredbyhumanactivities.Fossilfueluseandland-usechangesaredrivingtheongoing,rapidriseinatmosphericCO2andotherso-calledgreenhousegases.Concernsaboutthepotentialeffectsonregionalandglobalclimatemotivatethis…     

东北黑土区土壤剖面地温和水分变化规律

东北黑土区土壤侵蚀的结果使土壤在坡面上发生再分配,土壤腐殖质层厚度的空间变异增大。腐殖质层厚度的变化又引起地温和土壤水分等土壤物理性质的变化,地温和水分是影响和反映冻融侵蚀作用的重要因子,也是影响地表和土壤剖面物质运移的重要因素。本文通过实测不同厚度腐殖质层剖面的地温和土壤水分,分析了地温和水分随时间和土壤剖面深度的变化规律。结果显示腐殖质层厚度对土壤温度和含水量有显著影响,腐殖质层较厚的剖面解冻速度比薄层黑土区要慢,不同深度土层温度到达0℃的日期也不相同,腐殖质层较厚的剖面冻结时间要滞后1周左右。同时,腐殖质层较厚的黑土区土壤含水量明显大于薄层黑土区,土壤水分运移的深度范围也大。     

论山西褐土区农田土壤干燥化问题

以山西褐土区离石、忻州、太原、寿阳、临猗等地玉米、小麦农田为主要研究对象,选取5个代表性样点12个剖面采集0~600cm深度土壤样品,研究分析不同季节土壤垂直剖面水分状况。结果表明,该区玉米、小麦等农田中普遍存在土壤干层,轻度和中度干层都有显现;季节性干层的存在是该地区农作物易于发生干旱灾害的主要原因;晋中玉米地轻度干层发育到了600cm以下;晋南由于长期气候干旱,导致干燥化程度加重,轻度土壤干燥化也已发育到了600cm;晋西玉米地400cm接近轻度干化,晋北玉米地轻度干层也已达到600cm深度。农田季节性干层、深层土壤干层的出现严重影响了农田土壤的水循环;降水量少是本区农田干层产生的主要原因,但农田生产力提高、植被密度和蒸发对临时性干层形成的影响也不可忽视;选择低耗水、深根系的旱地作物,同时合理密植、有条件的地方实施灌溉等都是减缓农田干层的有效途径。     

甲氨基阿维菌素苯甲酸盐对黑土区农田土壤动物群落的影响

甲维盐属高效半合成抗生素杀虫剂。在哈尔滨市典型黑土农田区,研究不同浓度甲维盐处理对土壤动物群落结构的影响。结果表明:甲维盐处理显著降低了土壤动物群落的个体密度和类群数量,且这种趋势随着甲维盐浓度的增加而增强;显著改变了群落的垂直分布格局,表聚性特征被削弱,使动物较多地聚集于5~15 cm土层;改变了群落多样性特征,其中螨类和跳虫对多样性的贡献相对较大;显著改变了表层土壤化学性质,但不同动物类群对土壤环境变化的响应规律不同,螨类和跳虫对甲维盐干扰具有较强的适应能力。甲维盐处理可以显著改变黑土区农田土壤动物群落结构,浓度是影响该过程的重要因素,施用杀虫剂时需慎重评价其生态后果。     

Quantifying soil variability in GIS applications: II Spatial distribution of soil properties

Abstract

Application of Geographical Information Systems (GIS) to environmental problems requires a spatial delineation of soil properties and some a priori knowledge of their variability. In the U.S.A. estimated soil properties are available from soil surveys published by the National Cooperative Soil Survey. However, information on the extent and nature of their variability is generally lacking. To remedy the situation, variability of selected soil properties measured at farm and watershed scales was compared with published values using geostatistical methods. Results showed that the variability of bulk density and hydraulic conductivity can be estimated by comparing regularized variograms of measured and published values. An overlay method was proposed that combines measured and published delineations of soil properties into an overlay with the properties of both. The technique makes it possible to incorporate variability into a GIS analysis using data available from published soil surveys.     

盐碱荒地开垦年限对表层土壤盐分的影响

 以典型荒漠区原生盐碱荒地及开垦农田为研究对象,通过对比研究,以阐明原生盐碱荒地开垦后不同管理措施下土壤可溶盐总量的变化规律,开垦后土壤剖面中可溶盐总量的垂直分布和季节变化规律。结果表明：开垦显著降低了0～50 cm土壤的可溶性盐含量,开垦达100 a以上老耕地的可溶性盐含量（2.31 g/kg）仅为原生盐碱荒地（26.62 g/kg）的11%;长期的耕作改变了土壤可溶性盐分在土层中的分布,原生荒漠土壤盐分具有鲜明的表聚特征,0～30 cm土层的盐分含量占整个土壤剖面的79%,开垦50 a后,土壤中的盐分分布趋于均匀,各离子浓度的垂直分布不再明显;开垦使土壤中的盐分离子组成也发生了变化,Cl^-、K⁺、Na⁺离子浓度降低,而SO₄^2-、Mg²⁺、Ca²⁺离子浓度增加,耕作层土壤由SO₄^-2-Cl^-1盐土转变为Cl^-1-SO₄^-2盐土;盐碱荒地土壤可溶盐浓度伴随着降水变化具有显著的季节变化特征,而季节对开垦耕地没有显著影响。总体而言,盐碱荒地经过多年开垦利用后,土壤可溶性盐分和pH值均显著降低。     

Content and densities of soil organic carbon in urban soil in different function districts of Kaifeng

Urban soil, forming along with the development of city, has unique properties of soil organic carbon. On the basis of field investigation and laboratory analysis, soil organic carbon (SOC) of Kaifeng city was studied, and the results showed that the characteristics of SOC were different not only among function districts in urban area, but also between urban area and suburbs. The order of SOC in topsoil was industrial district > recreational district > traffic district > cultural/educational district > residential/administrative district. The density of soil organic carbon (SOCD) in both topsoil and profile followed the orders of recreational district > industrial district > traffic district>cultural/educational district > residential/adminis- trative district, and cultural/educational district > traffic district>industrial district>recreational district > administrative/residential district, respectively. SOCD in both topsoil and profile decreased along the transection line from urban area to suburbs and urban area had 2.53-fold more SOCD in topsoil and 1.56-fold more SOCD in profile than suburbs, respectively. SOC decreased with the depth and was mainly distributed within the scope of 0–30 cm. The variances of SOC in urban area were more complicated than that in suburbs.     

Content and densities of soil organic carbon in urban soil in different function districts of Kaifeng

Urban soil, forming along with the development of city, has unique properties of soil organic carbon. On the basis of field investigation and laboratory analysis, soil organic carbon (SOC) of Kaifeng city was studied, and the results showed that the characteristics of SOC were different not only among function districts in urban area, but also between urban area and suburbs. The order of SOC in topsoil was industrial district > recreational district > traffic district > cultural/educational district > residential/administrative district. The density of soil organic carbon (SOCD) in both topsoil and profile followed the orders of recreational district > industrial district > traffic district>cultural/educational district > residential/administrative district, and cultural/educational district s>traffic district>industrial district>recreational district > administrative/residential district, respectively. SOCD in both topsoil and profile decreased along the transection line from urban area to suburbs and urban area had 2.53-fold more SOCD in topsoil and 1.56-fold more SOCD in profile than suburbs, respectively. SOC decreased with the depth and was mainly distributed within the scope of 0–30 cm. The variances of SOC in urban area were more complicated than that in suburbs.     

福建土壤贫瘠化特征

探讨了福建土壤养分的时、空变异及贫瘠化特征。分析认为:除自然因素外,人为因素在土壤贫瘠化特征的形成上占主导地位,特别是侵蚀增加和耕作管理失调造成土壤养分循环与平衡的紊乱,最终引起土壤贫瘠化。     

Dependence of sand soil compressibility on soil physical properties

A relationship between soil physical properties and its compressibility has been analyzed.The formulae to determine soil density and porosity have been substantiated in compression tests.The regularity of changes in compressibility of thawed sand soils with various degrees of water content has been experimentally identified.     

开封市不同功能区城市土壤有机碳含量与密度分析(英文)

Urban soil, forming along with the development of city, has unique properties of soil organic carbon. On the basis of field investigation and laboratory analysis, soil organic carbon (SOC) of Kaifeng city was studied, and the results showed that the characteristics of SOC were different not only among function districts in urban area, but also between urban area and suburbs. The order of SOC in topsoil was industrial district > recreational district > traffic district > cultural/educational district > residential/administrative district. The density of soil organic carbon (SOCD) in both topsoil and profile followed the orders of recreational district >industrial district > traffic district>cultural/educational district > residential/adminis- trative district, and cultural/educational district > traffic district>industrial district>recreational district > administrative/residential district, respectively. SOCD in both topsoil and profile decreased along the transection line from urban area to suburbs and urban area had 2.53-fold more SOCD in topsoil and 1.56-fold more SOCD in profile than suburbs, respectively. SOC decreased with the depth and was mainly distributed within the scope of 0-30 cm. The variances of SOC in urban area were more complicated than that in suburbs.     

荒漠区食细菌线虫对生物土壤结皮下土壤酶活性的影响

作为土壤的重要生物组分,食细菌线虫影响土壤的能量流动和物质循环,但它在荒漠生态系统的作用仍不清楚.为探明土壤食细菌线虫对荒漠区土壤的影响,以腾格里沙漠东南缘人工植被固沙区生物土壤结皮覆盖的沙丘土壤为研究对象,分别采集藻-地衣和藓类结皮及结皮下0-10cm土样,按每克土壤10、30、60、90、120、150条的密度接种...     

东北黑土区坡耕地土壤侵蚀对影响因素响应的定量分析

东北黑土区坡地耕作方式多样,侵蚀过程复杂,形成了强烈的水土流失,须加强土壤侵蚀影响因子对产流产沙影响的定量化研究.本文利用2013-2017年东北典型黑土区海伦市光荣小流域不同处理方式的坡耕地径流小区监测数据,采用K均值聚类法和通径分析法,系统研究了不同降雨类型事件中坡耕地产流产沙对影响因素的响应.研究结果发现,研究区...     

Effect of soil structure on soil fauna in a desert wadi in Southern Egypt

This study investigates the soil fauna in a part of the rainless desert of southern Egypt. Three sites were examined: two downstream of Wadi Allaqi, both of which have been inundated by the water of Lake Nasser for several years. The third site is in Wadi Quleib, a principal tributary of Wadi Allaqi which was not inundated. Soil fauna were collected by pitfall traps during April-November 1989. Data were treated by multivariate analysis techniques, including correspondence analysis and ascending hierarchic classification. Most species were Arthropoda, particularly Coleoptera (7 species). Wadi Quleib was richer than Wadi Allaqi both in number of species and density. In Wadi Allaqi, the first site was richer than the second, both in species and density. These differences are partially related to differences in soft texture between Wadi Quleib and Wadi Allaqi, and to the presence of dense groves of Tamarix nilotica in the first site of Wadi Allaqi.     

降雨量、土壤蓄水量对流动沙地土壤水分深层渗漏的影响

土壤水分深层渗漏是陆地近地层水分循环的重要环节。利用土壤水分深层渗漏记录仪对毛乌素沙地典型流动沙丘不同深度土层的土壤渗漏水量连续进行两年定点监测。结果表明：（1）2016年生长季（4月1日至10月31日）降水量为2017年的1.93倍,但50、100、200 cm沙层的渗漏水量分别是2017年同期的4.53、5.53,5.22倍。同时,渗漏水量与降雨量及土壤蓄水量的波峰较一致。（2）强降雨对深层渗漏水量的影响较大,土壤蓄水量的变化也与深层渗漏水量密切相关;降雨量较小时,土壤蓄水量与深层渗漏水量之间的关系更为密切。在连续降雨过程中,越往深处,渗漏的产生通常是多次降雨过程累积的结果,将土壤蓄水量作为中间变量,能更好地分析土壤深层渗漏过程。（3）当天蓄水量与次日渗漏水量的相关系数较高,土层越深,深层渗漏水量与土壤蓄水量的相关系数增加,二者之间的线性拟合的R²也相应增加。     

Capacity of soil loss control in the Loess Plateau based on soil erosion control degree

The capacity of soil and water conservation measures, defined as the maximum quantity of suitable soil and water conservation measures contained in a region, were determined for the Loess Plateau based on zones suitable for establishing terraced fields, forestland and grassland with the support of geographic information system (GIS) software. The minimum possible soil erosion modulus and actual soil erosion modulus in 2010 were calculated using the revised universal soil loss equation (RUSLE), and the ratio of the minimum possible soil erosion modulus under the capacity of soil and water conservation measures to the actual soil erosion modulus was defined as the soil erosion control degree. The control potential of soil erosion and water loss in the Loess Plateau was studied using this concept. Results showed that the actual soil erosion modulus was 3355 t?km^-2?a^-1, the minimum possible soil erosion modulus was 1921 t?km^-2?a^-1, and the soil erosion control degree was 0.57 (medium level) in the Loess Plateau in 2010. In terms of zoning, the control degree was relatively high in the river valley-plain area, soil-rocky mountainous area, and windy-sandy area, but relatively low in the soil-rocky hilly-forested area, hilly-gully area and plateau-gully area. The rate of erosion areas with a soil erosion modulus of less than 1000 t?km^-2?a^-1 increased from 50.48% to 57.71%, forest and grass coverage rose from 56.74% to 69.15%, rate of terraced fields increased from 4.36% to 19.03%, and per capita grain available rose from 418 kg?a^-1 to 459 kg?a^-1 under the capacity of soil and water conservation measures compared with actual conditions. These research results are of some guiding significance for soil and water loss control in the Loess Plateau.     

内蒙古典型草原区土壤硬度与土壤水分的空间变化分析——以锡林浩特为例

近些年来,内蒙古草原及其变化已经受到有关方面的关注,通过研究调查内蒙古草原区的几个典型植被类型,共49个样地的土壤硬度与土壤水分。土壤硬度测量深度为0~20 cm,土壤水分测量深度为0~40 cm(10 cm取一个土样),并分析了两者的空间分布规律。分析结果显示,典型草原三种植被类型的土壤硬度随其深度增加而增加,而就全部样地来说,土壤水分随其土壤深度增加没有明显的变化。土壤硬度与土壤水分的相关性不强。通过49个样地的四层硬度进行PCA分析,显示出四层硬度对测量点第一主成分的作用差不多,这样,可以求取四层硬度的平均值作为该测量点的硬度,利用Arcinfo软件形成硬度分布图,看出本研究区的土壤硬度大致可以分成3区域:北部硬度较大,中部其次,南部沙地硬度较小。