汉江支流浰河航道整治工程土方综合利用研究

汉江支流浰河航道整治工程弃土方量巨大,存放难度大。文章阐述了浰河航道整治工程的土方综合利用原则和方式,提出了土方综合利用方案,研究了土方平衡和调配内容,经计算,土方综合利用可取得较好的经济效益、社会效益和生态环保效益。希望该研究成果为其他类似工程的土方综合利用提供参考借鉴。

京杭运河常州市区段改线工程土方综合利用地质勘察

传统的土方地质调查一般是针对块状地段的,而如何对条带状地段土方合理地调查成了一个新的课题。本文 采用纵向分段、横向分类的方法。运用钻探、静力触探、坑探等多种勘察手段,对京杭大运河常州市区段改线工程的土方 进行了地质勘察,并为其合理地运用于公路工程提供充分的地质依据。

航道整治工程土方综合利用途径与方法研究——以连云港港疏港航道整治工程为例

连云港港疏港航道整治工程中产生了大量的土方,文章对其综合利用的途径与方法进行分析。考虑机械设备、运输成本、土质条件和地形地势等因素影响,确定该项目土方利用半径为3km,给出了园区利用、砖瓦建材企业利用、新型护岸结构利用、造地利用和新农村建设利用等5种土方综合利用途径。

连云港港疏港航道整治工程土方综合利用效益分析

连云港港疏港航道整治工程施工过程中产生大量土方,土方的综合利用成为整治工程中的新问题。文章在对综合利用方式进行研究的基础上,对连云港港疏港航道整治工程土方的综合利用效益进行分析,重点分析其社会、经济和生态效益。

杨林塘航道整治工程土方综合利用研究

本文结合杨林塘航道整治工程的工程土方综合利用方案,阐述了土方综合利用的原则,对土方综合利用的方法和效益进行了研究,可为其它航道工程的土方处理提供参考。

土石方调配中经济运距的确定

根据借土的 4种组合方式得出的土方综合单价与利用弃土方 (或石方 )的运输单价相比较 ,得出在多少运距范围内采取何种组合方式经济的结论 ,供同行参考。

Changes of soil organic carbon and nitrogen in forage grass fields,citrus orchard and coniferous forests

Dynamic quantitative assessment of soil organic C and N is an available approach to understand the exact impact of land management on soils fertility. In this study the biomass of plants and content of soil organic C and N were compared in four typical land use systems which were planted with Ryegrass (Lolium multiflorum Lam.), Bahiagrass (Paspalum notatum Flugge.), Citrus (Citrus reticulata Blanco.), and Masson pine (Pinus Massoniana Lamb.) during 10 years in south China. Although biomass of plants in these four land use systems was nearly at the same level in the former investigation, total biomass for Ryegrass (RG), Bahiagrass (BG) was 3.68 and 3.75 times higher than that for Citrus (CT), and 2.06 and 2.14 times higher than that for Masson pine (MP) over 10 years of cultivation, respectively. Especially, underground total biomass for both RG and BG was over 10 times larger than that for CT and MP, indicating that forage grasses was much more beneficial to increase organic C and N storage in soils than CT and MP. The change content of soil organic C and N mainly occurred within soil depth of the 0–40 cm. The increased content of soil organic carbon and nitrogen was for 1.5 t·hm?2 and 0.2 t·hm?2 in the soil with planting RG and BG, and was for 1.2 t·hm?2 and 0.02 t·hm?2 in the soil with planting CT. An average loss was for 0.4 t·hm?2 and 0.04 t·hm?2 in the soil with planting MP during 10-year period. Keywords Soil organic carbon - Soil organic nitrogen - Dynamic change - Land use - Quantitative assessment CLC number S153.61 Document code A Foundation item: This research was partly supported by National Natural Science Foundation of China (30100144), and by Scientific Committee of Shenyang City (1011501900).Biography: WANG Xiao-ju (1967-), mail, Ph.D. Researcher in Center for Environmental Science in Saitama. Saitama Prefecture 347 0115, Japan.Responsible editor: Zhu Hong

Effects of Different Land Use Types on Soil Organic Carbon and Carbon Management Index in Karst Area

[Objective] The aim was to reveal changes of soil organic matter fraction and their corresponding carbon management indexes as affected by different land use types.[Method]Soil organic carbon,active soil organic carbon and soil carbon management index（CMI）of different land use types in Guilin Maocun karst area were studied.Sampling with field investigation and laboratory testing was carried out.Heavy potassium chromate method was adopted to determine soil organic matter.333 mmol/L KMnO4 oxidation method was used to determine active organic carbon.[Result]With active soil organic matter increasing,the differences of CMI between different land use types were bigger.The CMI value of different land uses was shrubforest paddy fielddry farmland.The statistical analysis showed that labile organic matter was related with major soil properties at a significant level.[Conclusion]Labile organic matter could be used to reveal the influence of different land use types on soil organic matter and carbon management index in karst area.

Effect of Different Land Use Patterns on Physical Properties of Soil Water in Yellow River Wetland in Shaanxi Province

[Objective] This study was to reveal the effect of different land use patterns on physical characteristics of soil water in the Yellow River wetland in Shaanxi Province.[Method]Taking Yellow River wetland in Shaanxi Province as experimental plot,we compared the physical properties of the soil water under different land use patterns and studied the physical properties and the change law of soil water during the wetland degeneration process.[Result]Under different land use patterns,soil bulk density rose with the increase of soil depth.During the degeneration process of from river wetland to reclaimed wetland（paddy field）,finally to abandoned land owing to salinization,the mean soil bulk density reduced correspondingly from 1.474 to 1.522 g/cm3,finally to 1.593 g/cm3 when abandoned.Accompanying wetland degeneration,soil became compact increasingly,and the indicators of soil porosity（total porosity,capillary porosity,non-capillary porosity）were also reduced with the change of land use patterns,in which,capillary porosity and total porosity reached the extremely significant level with the change of land use patterns,and non-capillary porosity reached significant level.The changes of soil porosity condition accelerated the deterioration of wetland.Under different land use patterns,the maximum soil moisture capacity,capillary moisture capacity and minimum moisture capacity all showed a similar change law.Compared with wetland,the maximum soil moisture capacity of reclaimed land（paddy field）and salinized land respectively decreased by 5.7% and 22.3%,capillary moisture capacity by 0.2% and 19.4%,minimum moisture capacity by 2.7% and 15.9%.Of the three land use patterns,wetland displayed both higher water holding capacity and water drainage capacity over reclaimed land（paddy field）and salinized land.By comparison with wetland,the reclaimed land（paddy field）and salinized land respectively decreased by 12.4% and 15.2% in total water holding capacity,and by 2.7% and 15.9% in total water drainage capacity.[Conclusion]To conserve the water resource in Yellow River wetland,regulate the hydrological cycle and enhance drought and water logging resistances,it should be noted that reasonable countermeasures be taken to exploit the state-owned forest land and paddy field around the wetland and the related resources.

Seasonal Dynamics of Biomass under Different Land Use Patterns

[Objective] The aim was to study seasonal dynamics of biomass under different land use patterns. [Methed] Aboveground biomass and underground biomass of plants under 3 different surface cover conditions of Stipa krylovii, Leymus chinensis and farmland were determined in growing season （ from May to October） of 2008. [ Result ] The aboveground biomass of Stipa krylovii, Leymus chinensis and farmland in August all reached the highest value, which of Stipa krylovii, Leymus chinensis and farmland was 287.91,117.05 and 193.59 g/m2, respectively. The total biomass of plant roots of the 3 plots in July all reached the highest value, which of Stipa krylovii, Leymus chinensis and farmland was 1 683.9, 1 601.9 and 513.9 g/m2, respectively. Leymus chinensis had the biggest biomass ratio of upper plant roots （0 - 15 cm） to lower plant roots （15 -30 cm）, Stipa krylovii took second place, and farmland had the smallest one. ~ Conclusion The research provides theoretical basis for the ecological environment protection of ecological fragile area.

Study on Influences of Different Land Use Types on Soil Qualities in Plateau Karst Depression

[Objective] The aim was to study influences of different land use ways on soil qualities in plateau karst depression.[Method] Different land use types were divided by topographic map of 1∶10 000 scales and soil properties of physics and chemistry were analyzed.[Result] The results showed that the variation trend of soil depth(A+B stratum)was slope plough(include returning farm to forest)land>natural forest land>planted forest land>shrub forest land,and relative indexes changing regularities of soil...

Soil Moisture Characteristics in Karst Area with Different Land Use Types

Ecological efficiency changes of soil moisture were researched in karst areas with different land type uses, including farmland, abandoned farmland （1 y） and shrub land （1 y）, sparse wood land （15 y）, secondary forest （25 y） and the re- sults showed that physical property of soil was not a simple ＂improvement＂ process during land type evolution. Specifically, from farmland to secondary forest, the con- tent of topsoils changed from being washed away to accumulation and soil bulk density changed from increasing to decreasing. For example, soil bulk densities of abandoned farmland and shrub land increased by 6.6% and 11.57% compared with farmland, and of sparse wood land and forest land decreased by 5.0% and 10.0%. The change trend of soil bulk density was just in contrary to total porosity. Available water capacity was the lowest of shrub land, but increased in rest land types. The increase tended to be volatile in 5.1%-12.5% of different land types and water-sta- ble aggregate content （〉0.25 mm） reached the highest of sparse wood land. The destruction rate, however, was declining in the process of land type evolution and the increase was in the range of 34.0%-64.7% compared with farmland. The de- struction rate of aggregate was of negative correlation with organic matter. Water- holding capacity was the best of forest land and abandoned farmland and the poor- est of shrub land, close to sparse wood land. Water-supplying capacity from high to low was as follows： farmland〉sparse wood land〉secondary forest〉shrub land〉a- bandoned farmland. It is obvious that water-holding capacity and water-supplying capacity are not consistent, but both are closely related to the content of soil clays, porosity, and aggregate stability.

Influence of land use characteristics and trip attributes on commuting mode choice: a case of Nanjing

The effects of socio-demographics, land use characteristics and trip attributes on the commute mode choice are studied with a nested logit （NL） model. Based on the random utility maximum theory, the NL model is formulated. The analysis is carried out in the main area of Nanjing. Direct and cross elasticities are calculated to analyze the effects of travel time and travel cost on the selection of travel mode choice. The results reveal that the non-motorized travel modes are more attractive in the areas with higher housing and employment accessibility and car owners are found to be more likely to commute to work by car. The bus and subway choice probabilities are more sensitive to changes in travel times than to changes in travel costs. In conclusion, a comprehensive public transit system and effective integration of land use and transportation policies help to relieve the traffic congestion levels caused by the increasing urban sprawl.

Effects of Different Land Use Patterns on Soil Microbial Quantity and Activity in Hongta District,Yuxi City

[Objective] This study aimed to investigate the effects of different land use patterns on soil ecological environment. [Method] Total three representative land use patterns （corn field, cherry tree land, wood land） were selected from Hongta District, Yuxi City, and under these three patterns, soil microbial quantity and activity were studied. [Result] Under the three land use patterns, soil microorganisms were domi- nated by bacteria; soil microbial quantity ranked as wood land＇s〉cheery tree land＇s〉 corn field＇s; and total microbial activity, catalase activity and urease activity all ranked as cherry tree land＇s〉wood land＇s〉corn field＇s. [Conclusion] Soil microbial activity and functions are related to farmland management measures, as well as land use pattern and soil nutrients.

Relationships among Glomalin Related Soil Protein,Soc and Soil Texture under Different Land Use Types

[Objective] The aim was to reveal the effects of different land use types on soil composition. [Method] GPRS,soil organic carbon content and soil texture in 3 depths (0-10,10-20,20-50 cm) of 5 main kind of selected land use type were examined in Hainan. [Result] The results showed that GRSP and SOC content of four artificial land use types decreased compared with the natural secondary forest land,the GRSP content of all samples ranged from 0.53-4.80 mg/g,accounting for 7.9%-23.4% of the SOC,which means that GRSP was one important component of SOC pool in soil. The ratio of GRSP to SOC was significantly different among land use types but the depths. GRSP and SOC exhibited obvious vertical distribution pattern. GRSP was significantly positively related to SOC and sand content but negatively related to silt and clay content. [Conclusion] The sand content determined the GRSP content significantly and loam was better matrix for GRSP accumulation than clay.

Changes of Soil Labile Organic Carbon in Different Land Uses in Sanjiang Plain, Heilongjiang Province

In the Sanjiang Plain,Northeast China,the natural wetland is undergoing a rapid conversion into agricultural land,which has resulted in drastic ecological changes in the region. To investigate the effects of different land uses on soil labile organic carbon,soils of Calamagrostis angustifolia wetland,Carex lasiocarpa wetland,dry farmland,paddy field,forest land and abandoned cultivated land were collected for measuring the contents of soil microbial biomass carbon (MBC),dissolved organic carbon (DOC),readily oxidizable carbon (ROC) and carbohydrate carbon (CHC). The results show that soil organic carbon contents follow the order: Carex lasiocarpa wetland>Calamagrostis angustifolia wetland>forest land>paddy field>dry farmland. The contents of MBC and DOC in Calamagrostis angustifolia and Carex lasiocarpa wetlands are significantly higher than those in other land use types. The contents of CHC and ROC are the highest in Calamagrostis angustifolia wetland and the lowest in dry farmland. The contents of all the labile organic carbon increase along with the years of abandonment of cultivated land. The ratios of MBC,DOC and ROC to SOC also follow the order: Carex lasiocarpa wetland>Calamagrostis angustifolia wetland>forest land>paddy field>dry farmland,while the ratio of CHC to SOC is paddy field>forest field>Carex lasiocarpa wetland>Carex lasiocarpa wetland>dry farmland. When natural wetlands were cultivated,the activity of soil organic carbon tends to reduce in some extent due to the disappearance of heterotrophic environment and the reduction of vegetation residue. Thus,the abandonment of cultivated land is an effective way for restoring soil organic carbon.

Spatio-temporal Patterns of Intra-urban Land Use Change in Beijing,China Between 1984 and 2008

Urban internal structure is essential information for urban geography researchers and urban planners or managers. This research aims to examine the spatial structure changes of internal urban land use based on the interpreted datasets of 1984 and 2008. Spatio-temporal patterns of internal land use conversion and urban expansion are analyzed, and then dominant driving factors (e.g., social economy, population growth and urban planning) were identified. The results indicate that Beijing′s intra-urban layout has experienced tremendous adjustment from compact to disperse configure, otherwise its function objects have shifted from the major economic and industrial development before the 1990s to the combination with cultural, high-technological and inhabitable city at present. The dominant urban land use transformations include the relocation of industrial lands from core districts to suburban or other provinces, and the accelerating expansion of residential areas and green spaces for supplying the demand of housing and ecological protection. Although Beijing′s urban planning has experienced three major adjustments and improvement since the 1980s, its optimization of urban internal patterns still remains a challenge.

Method for Evaluating the Degrees of Land Use Sustainability of Mountainous County and its Application in Yunnan Province,China

The evaluation of sustainable land use is the key issue in the field of studying the sustainable land utilization. In general analysis, the sustainable land use is evaluated respectively from its ecological sustainability, economic sustainability and social sustainability in China and other countries in recent years. Although this evaluation is an important work, it seems insufficient and hard to comprehensively reflect the whole degree of land use sustainability. Thus, to make up this deficiency, this paper brings forward the evaluation indexes, which make it possible to quantitatively reflect the whole degree of land use sustainability, namely, the concept of ＂degrees of overall land use sustainability＂ （Dos）, and research and measurement development of the method of and calculation in Dos. Taking the evaluation of the degree of land use sustainability in county regions of Yunnan Province as the actual example for analysis, results are basically as follows： 1） The degree of land use sustainability （Dos） is the ration index to organically and systematically integrate the degree of ecological friendliness （DeF）, the degree of economic viability （Dev） and the degree of social acceptability （Dsa）, able to comprehensively reflect the whole sustainability degree of regional land use 2） Based on the value of Dos, the grading system and standard for the sustainability of land use may be established and totally divided into five grades, namely, the high-degree sustainability, middle-degree sustainability, low-degree sustainability, conditional sustainability and non-sustainability. Meanwhile, the standard for distinguishing sustainability grades has also been confirmed so as to determine the nature of sustainability degrees in different grades. This makes the possibility for the combination of nature determination with ration in research result and provides with the scientific guideline and decision-making gist for better implementation of sustainable land use strategy. 3） The practice in evaluation of sustainability degree in county regional land use in Yunnan shows that the value of the degree of land use sustainability （Dos） of whole Yunnan Province is only 58.39, belonging to the grade of low-degree sustainability. Two thirds of counties in the whole province represent the grade of ＂conditional sustainability＂ and ＂non-sustainability＂ in the sustainability of land use. Among these counties, 11.11 % shows ＂non- sustainability＇. The lowest degree of land use sustainability appears especially in the middle plateau mountain region of Northeast Yunnan, where the value of Dos in most counties （districts） is below 40 %, belonging to the grade of ＂non-sustainability＂. The sustainability degree in the karst mountainous region in lower-middle plateau mountain region in Southeast Yunnan is generally low and the value of sustainability degree （Dos） in most of the counties （cities and districts） is below 55. The value of sustainability degree （Dos） in most of the counties （cities and districts） in the north, west, northwest and southwest parts of Yunnan is below 55. This article also analyzes the reasons of low degree of sustainability in land use in Yunnan and puts forward the countermeasures to increase the degree of sustainability in land use in the whole province.

Land Use and Soil Organic Carbon in China’s Village Landscapes

Village landscapes, which integrate small-scMe agriculture with housing, forestry, and a host of other land use practices, cover more than 2 million square kilometers across China. Village lands tend to be managed at very fine spatial scales （≤ 30 m）, with managers both adapting their practices to existing variation in soils and terrain （e.g., fertile plains vs. infertile slopes） and also altering soil fertility and even terrain by terracing, irrigation, fertilizing, and other land use practices. Relationships between fine-scale land management patterns and soil organic carbon （SOC） in the top 30 cm of village soils were studied by sampling soils within fine-scale landscape features using a regionally weighted landscape sampling design across five environmentally distinct sites in China. SOC stocks across China＇s village regions （5 Pg C in the top 30 cm of 2 ×10^6 km^2） represent roughly 4% of the total SOC stocks in global croplands. Although macroclimate varied from temperate to tropical in this study, SOC density did not vary significantly with climate, though it was negatively correlated with regional mean elevation. The highest SOC densities within landscapes were found in agricultural lands, especially paddy, the lowest SOC densities were found in nonproductive lands, and forest lands tended toward moderate SOC densities. Bue to the high SOC densities of agricultural lands and their predominance in village landscapes, most village SOC was found in agricultural land, except in the tropical hilly region, where forestry accounted for about 45% of the SOC stocks. A surprisingly large portion of village SOC was associated with built structures and with the disturbed lands surrounding these structures, ranging from 〉 18% in the North China Plain to about 9% in the tropical hilly region. These results confirmed that local land use practices, combined with local and regional variation in terrain, were associated with most of the SOC variation within and across China＇s village landscapes and may be an important cause of regional variation in SOC.

Characteristics of heavy metals in soils under different land use in a typical karst area, Southwest China

This study investigated the distribution of six pollutant elements(Cr, Cu, Pb, Zn, Cd, and As), and their relationship to soil organic carbon(SOC) in five soil profiles in the Puding area. Results show SOC content decreased exponentially to the depth of soil profiles; the vertical distribution patterns of SOC in soil profiles were partially controlled by land use. The concentrations of these pollutant elements in most soils were lower than background values, indicating that the local soil was less likely to be contaminated by foreign inputs. Geo-accumulation index values of these elements in most soil samples were less than 1, suggesting that the soil of this area may not be polluted. The concentrations of Cr, Cu, As, and Zn in soils from all land use types were significantly negatively correlated with SOC contents. Geochemical approaches confirmed that the soil of this area was less influenced by pollutant elements.