城市土质地面鼠洞与地下井关联性调查

目的了解武汉马路边绿化带及老旧居民区土质地面鼠洞分布现状,检验城市地下井周边土质地面更容易有鼠洞的经验是否可靠。方法在武汉城区马路边绿化带、老旧居民区土质地面选全部落在距离井盖5 m范围内的"井盖附近样方"及所有点距离最近的地下井井盖超过5 m的"远离井盖样方",记录样方中鼠洞数量及与井盖是否"零距离"接触,分析多种因素与土质地面样方是否有鼠洞的关联性。结果 "井盖附近样方"及"远离井盖样方"鼠洞阳性率分别为7.3%和3.1%,具有显著性差异(P<0.001);鼠洞密度分别为0.052和0.018个/m2,具有显著性差异(P=0.005)。"零距离"和"非零距离"样方鼠洞阳性率分别为17.7%和3.1%,具有显著性差异(P<0.001);鼠洞密度分别为0.069和0.023个/m2,具有显著性差异(P<0.001)。马路边绿化带和老旧居民区样方鼠洞阳性率分别为2.4%和8.9%,具有显著性差异(P<0.001);鼠洞密度分别为0.030和0.040个/m2,具有显著性差异(P=0.037)。结论城市地下井盖附近土质地面更可能有鼠洞。

Technical efficiency and its determinants of the various cropping systems in the purple-soiled,hilly region of southwestern China

This study examines the technical efficiency(TE) differences among typical cropping systems of smallholder farmers in the purple-soiled hilly region of southwestern China.Household-,plot-,and crop-level data and community surveys were conducted to explore TE levels and determinants of typical cropping systems by using a translog stochastic frontier production function.Results indicate significant difference in TE and its determinants among cropping systems.The mean TEs of the rice cropping system(R),the rice-rape cropping system(RR),the rice-rape-potato cropping system(RRP),and the oil cropping system(O) are0.86,0.90,0.84,and 0.85,respectively,which are over 1.17 times higher than those of the maize-sweet potato-other crop cropping system(MSO) and the maize-sweet potato-wheat cropping system(MSW) at0.78 and 0.69,respectively.Moreover,Technical inefficiency(TIE) of different cropping systems is significantly affected by characteristics of the household as well as plot.However,the impact of land quality,mechanical cultivation conditions,crop structure,farming system,farm radius,household type,cultivated land area per capita,and annual household income per capitalon TIE vary by cropping system.Additionally,output elasticity of land,labor,and capital,as a group,is greater than the one of agricultural machinery and irrigation.Finally,when household-owned effective agricultural labor is at full farming capacity,optimal plot sizes for the R,RR,RRP,MSO,MSW,and 0 cropping systems are 1.12hm^2,0.35 hm^2,0.25 hm^2,2.82 hm^2,1.87 hm^2,and 1.17hm^2,respectively.

The effects of soil sand contents on characteristics of humic acids along soil profiles

It is generally accepted that the compositions and properties of soil organic matter （SOM） are influenced by many factors. In order to reveal the effects of soil texture on characteristics and dynamics of SOM and its sub-fraction, humic acid （HA）, along two soil profiles, a yellow soil profile and a purplish soil profile, under the same climate and vegetation conditions were determined. Results indi- cate that the decomposition and humification degrees of SOM and HA of the purplish soils are higher than those of the corresponding yellow soils indicated by A/O-A ratios of HAs, TOCs and HA yields of bulk soil samples, neverthe- less, the development degree of the purplish soil is lower than that of the yellow soil. The variations of E4/E6 ratios of HAs along the soil profiles indicate the overall molecular sizes of HAs decreased downward along the soil profiles. A/O-A ratios of HAs decreased downward along both the soil profiles indicate that humification processes decrease downward along both the soil profiles. Leaching of SOM shows significant effects on the distribution and character- istics of HAs in the yellow soil profile but the purplish soil profile, which is consistent with the higher hydrophobicity of HAs in purplish soils, shows that the distribution char- acteristics of SOM along the soil profiles are a complex result of the combination of soil texture and characteristics of SOM itself. The remarkably different sand contents are concluded tentatively as one of reasons to the differentdistributions and dynamics of HAs along the soil profiles, however, to profoundly understand the evolution and transport of SOM along soil profiles needs more researches.

Assessment of rapid impact compaction in ground improvement from in-situ testing

Ground improvement has been used on many construction sites to densify granular materials, in other word, to improve soil properties and reduce potential settlement. This work presents a case study of ground improvement using rapid impact compaction （RIC）. The research site comprises the construction of workshop and depots as part of railway development project at Batu Gajah-Ipoh, Malaysia. In-situ testing results show that the subsurface soil comprises mainly of sand and silty sand through the investigated depth extended to 10 m. Groundwater is approximately 0.5 m below the ground surface. Evaluation of improvement was based on the results of pre- and post-improvement cone penetration test （CPT）. Interpretation software has been used to infer soil properties. Load test was conducted to estimate soil settlement. It is found that the technique succeeds in improving soil properties namely the relative density increases from 45% to 70%, the friction angle of soil is increased by an average of 3°, and the soil settlement is reduced by 50%： The technique succeeds in improving soil properties to approximately 5.0 m in depth depending on soil uniformity with depth.

Flood Hazard Prediction from Soil Properties by Remote Sensing and Genographic Information System:A Case Study of Mae Rim Watershed,Chiang Mai Province,Thailand

Physiography and soil in Mae Rim watershed, Chiang Mai Province, Thailand were investigated by using aerial photographs and satellite image in conjunction with field work, and soil infiltration rate and soil shear resistance were measured in field. Many factors affecting runoff were analyzed using the Integrated Land and Water Information System (ILWIS). As a result, a model determining flood hazard was set up. Three maps including runoff curve number map, runoff coefficient map, and flood inundation map were created. In addition, the time of concentration was predicted.

Safety assessment of waste rock dump built on existing tailings ponds

The construction of waste rock dumps on existing tailing ponds has been put into practice in China to save precious land resources. This work focuses on the safety assessment of the Daheishan molybdenum mine waste rock dump under construction on two adjoining tailings ponds. The consolidation of the tailings foundation and the filling quality of the waste rock are investigated by the transient electromagnetic method through detecting water-rich areas and loose packing areas, from which, the depth of phreatic line is also estimated. With such information and the material parameters, the numerical method based on shear strength reduction is applied to analyzing the overall stability of the waste rock dump and the tailings ponds over a number of typical cross sections under both current and designed conditions, where the complex geological profiles exposed by site investigation are considered. Through numerical experiments, the influence of soft lenses in the tailings and possible loose packing areas in the waste rock is examined. Although large displacements may develop due to the soft tailings foundation, the results show that the waste rock dump satisfies the safety requirements under both present and designed conditions.

Influence of Prospecting and Crude Oil Production on Geoecological Parameters of Permafrost

The large reserves ofoil are disposed in zones of permafrost in shelf and continental fields. In Europe the subarctic and arctic tundra are abundant only in Nenetsky autonomous area and in the north-east of the republic of Komi. Oil and gas production activity has threatened richest biological resources and health of the population of the region. A singularity of petroliferous fields of the north of Russia is the existence of the thick strata of permafrost. On top of them different heat-insulating overlying layers （snow, biogenic covers） reside. State and dynamics of permafrost cause progressing dangerous exogenic geoecological processes, which are exhibited completely. State of permafrost is instituted by exchange of heat in near-surface strata of a geological section. During the development of oil fields there is a disturbance of a temperature schedule of permafrost. For estimation of technical attack the analytical computational method of influence of the different factors on value of annual heat exchange and prediction of geocryological conditions is proposed. It is shown, that such dangerous phenomena as degradation of permafrost and thermokarst would develop in the first place, which would cause the destruction of natural ecosystems.

The Impact of Land Fragmentation in the Qualitative and Quantitative Aspect of Seeds and Their Production

Due to the pedo-climate conditions in the region of Korca, this area is considered to be one of the most favorable regions for cultivating various kinds of plants such as cereals, vegetables, wood-trees, vineyards, etc. All the factors such as rain, temperature, the impact of sunlight, and the pathological structure of the land, make this region one of the most productive and qualitative among the others. Changing the political systems in Albania during the last decades in Albania had its own impact even in the agricultural aspect. Shifting from communism into a modem, capitalist economy built a huge barrier for farmers in their way to intensifying the agricultural production. Dividing the land according to the law number 7,501, was accompanied by a severe fragmentation of the plot, reducing the degree of mechanization and chemical process. In this paper, the authors will try to analyze the effect of law fragmentation in the regional farmers working process in the region of Korea, and other municipalities such as Bilisht and Maliq, nearby Korea. There were randomly interviewed 150 farmers, from which 30 from the municipality of Bilisht, 22 from Korca municipality and 15 from Maliqi. From each farmer, these were the variables taken into consideration： Total land area, irrigated land, the number of plots, the area planted with wheat, corn, vegetables, fruit, vineyards, and forages. All the data that were gathered and translated into figures have indicated statistic elements such as the average value of each variable, deviation or standard deviation, coefficient of variation, correlation and regression. For instance in the municipality of Bilisht, it has been concluded that between the total variable area and number of plots, the related correlation value of the correlation coefficient is r = ＋ 0.73 and the value of regression coefficient is R = 2.71. In this municipality, correlative links between the variable and the total area planted with wheat area, are of medium category, with a value of the correlation coefficient of r = ＋ 0.52 and the regression coefficient is R = 0.89. Regarding the studies in the municipality of Maliq, it has been a correlation link between the weak variable category： in the surface of the irrigated area and the land planted with vegetables and corn, the value of the correlation coefficient is r = ＋ 0.24 and the regression coefficient R = 2.11. In the municipality of Korea, among the variable of irrigated area and the surface of the land planted with vegetables, there is a weak correlative link with a value of the correlation coefficient r = ＋ 0.17 and the regression coefficient R = 0.58.

Total Carbon Storage in Himalaya Rangeland of Milke-Jaljale Area, Eastern Nepal

Rangelands occupy 51% of the terrestrial land surface, 23% total land of Nepal. It contains about 36% of the world＇s total carbon in above and belowground biomass. Rangelands can aid in the mitigation of rising atmospheric carbon dioxide concentrations via carbon storage in biomass and soil organic matter. A study on carbon stock on soil and vegetation at various altitudinal gradients in Milke-Jaljale rangeland area of Eastern Nepal was made. The study was carried out at three altitudinal gradients （above sea levels） Milke （3,000 m）, Gorujure （3,500 m） and Jaljale （4,000 m）. This method required establishing a transect line. Sample points were located by pacing the appropriate distances from the point of origin at a transect line. To determine distribution and quantity of plant carbon and soil organic carbon （SOC）, 45 sample points were established and 15 points were sampled from each study site. Total soil carbon was estimated as follows： 17.65 t/ha at Milke, 17.27 t/ha at Gorujure and 28.33 t/ha at Jaljale. Similarly, total vegetation carbon was estimated 22.68 t/ha at Milke, 29.79 t/ha at Gorujure and 42.54 t/ha at Jaljale. Highest elevation study site with least external disturbance （Jaljale area） had high storage of carbon in both cases vegetation and soil.

Mapping Soil Texture of a Plain Area Using Fuzzy-c-Means Clustering Method Based on Land Surface Diurnal Temperature Difference

The use of landscape covariates to variability of soil properties in similar estimate soil properties is not suitable topographic and vegetation conditions. for the areas of low relief due to the high A new method was implemented to map regional soil texture （in terms of sand, silt and clay contents） by hypothesizing that the change in the land surface diurnal temperature difference （DTD） is related to soil texture in case of a relatively homogeneous rainfall input. To examine this hypothesis, the DTDs from moderate resolution imagine spectroradiometer （MODIS） during a selected time period, i.e., after a heavy rainfall between autumn harvest and autumn sowing, were classified using fuzzy-c-means （FCM） clustering. Six classes were generated, and for each class, the sand （〉 0.05 mm）, silt （0.002-0.05 mm） and clay （〈 0.002 mm） contents at the location of maximum membership value were considered as the typical values of that class. A weighted average model was then used to digitally map soil texture. The results showed that the predicted map quite accurately reflected the regional soil variation. A validation dataset produced estimates of error for the predicted maps of sand, silt and clay contents at root mean of squared error values of 8.4%, 7.8% and 2.3%, respectively, which is satisfactory in a practical context. This study thus provided a methodology that can help improve the accuracy and efficiency of soil texture mapping in plain areas using easily available data sources.

Energy flux characteristics of seismic waves at the interface between soil layers with different saturations

Based on the multiphase poroelasticity theory describing the propagation of waves in the unsaturated fluid-saturated porous medium,the reflection and transmission coefficients of the seismic waves at the interface between soil layers with different saturations are obtained.Our unsaturated model consists of a deformable skeleton in which two compressible and viscous fluids(i.e.,water and gas)flow in the interstices.Three compressional waves(i.e.,P1,P2,and P3 waves)and one shear(i.e.,S wave)wave exist in the unsaturated soils.The expressions for the energy ratios of the various reflected and transmitted waves at the interface during the transmission and reflection processes are presented in explicit forms accordingly.At last,numerical computations are performed and the results obtained are respectively depicted graphically.The variation of the energy ratios with the incident angle,wave frequency and saturation degrees of the upper and lower soil layers is illustrated in detail.The calculation results show that the allocation of incident seismic waves at the interface is influenced not only by the angle and frequency of the incident seismic waves,but also by the saturations of the upper and lower soil layers.It is also verified that,at the interface,the sum of energy ratios of the reflected and transmitted waves is approximately equal to unity as was expected.This study is of importance to several fields such as geotechnical engineering,seismology,and geophysics.