济水源头之谜探析(一)

从文献记载、地质考古、历史演变等多方面对济水源头问题提出新的解答。研究结果表明《山海经》"济水出共山南东丘"是对史前济水的客观真实记载,共山指济源盆地北缘的太行山,东丘指济源盆地内北东走向拦蓄水流的高丘,史前古济水发源于共山南东丘的济源古湖盆,水量巨大且水清沙少,与盆地南缘的黄河相互分隔、各自独立,形成独立的济水源头水系。同时,对济水源头与沁河、沇水、氵聯水的关系以及济水源头从共山南东丘的济源古湖盆到济源城西北的东西二源的演变过程进行了分析。

济水源头之谜探析(二)

济水源头问题错综复杂,大体有王屋山说、东西二源说以及黄河说。这些说法似乎都有依据,然而细究起来,却并没有科学地描述出济水史前的模样。《山海经》中提出"济水出共山南东丘"的说法,值得玩味。这绝不是远古的神话传说或作者的主观想象,而是史前济水的客观真实记载。考察当地的地质特点,可以认为共山就是济源盆地北缘的太行山,而东丘则是济源盆地内北东走向拦蓄水流的高丘。综合分析济源一带的地质地貌,古济水可能发源于"共山南东丘"的"济源古湖盆"。

The characteristics of gully erosion over rolling hilly black soil areas of Northeast China

In this study,short-term gully retreat was monitored from the active gullies selected in representative black soil area,using differential global positioning system(GPS).With the support of geographic information system(GIS),multi-temporal digital elevation models(DEM) were constructed from the data collected by GPS and used for further analysis.Based on the analysis of multi-temporal DEM,we discussed the erosion-deposition characteristics within gully and a developing model for black soil gully area of Northeast China was proposed.The results are:(1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m,gully area extended 170-400 m2,net gully eroded volume 220-320 m3,and gully erosion modulus 2200-4800 t?km?2?a?1.(2) Compared with the mature gully the initial gully grows rapidly,and its erosion parameters are relatively large.The erosion parameters have not only to do with flow energy,but also with the growth phase.(3) There are significant seasonal differences in gully erosion parameters.The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head and net erosion in rainy season.(4) It is remarkable for freeze-thaw erosion in the black soil area of NE China.The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004,and the distance of gully head retreated maximally 6.4 m.(5) Due to freeze-thaw action and snowmelt,gully is primarily in the interior adjustment process in winter and early spring.There are much more depositions compared with that during rainy season,which can almost happen throughout the gully,while erosion mostly occurs near head,esp.for gullies having a relatively long history of development.On the other hand,the process of energy exchange with exterior dominates in rainy season.It is considered that this cyclic process is an important mechanism for gully growth in high latitude or/and high attitude regions.

Snstainable Land Use in Hilly Red Soil Region of South-eastern China

In the Present work, an integrated analysis of natural and socio-economic conditions in the hilly redsoil region of southeastern China is made by nieans of a Geographic Information System. Particular em-phasis lies on soil degradation and other adverse ecological and environmental effects of the prevalent andirrational land-use systems of mono-and valley-agriculture in the region. Moreover, taking into account thesimultaneous existence of enormous potentials and serious constraints and the high diversity and complexityof the biophysical and socio-economic environments, a set of strategies and counterineasures are also prc-posed for appropriate management of environmental resources, in terms of maintaining harmony betweenutilization and conservation of the natural environment, including 1) adjustment of the agricultural structureand optimization of ecological patterns of stereo-agriculture; 2) improvement and integrated exploitation ofthe low-yield lands and wastelands; 3) rehabilitation and conservation of soil and water resources; and 4)establishment of production bases of tropical and subtropical cash crops and fruits.

Relationship Between Soil and Water Conservation Practices and Soil Conditions in Low Mountain and Hilly Region of Northeast China

The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixing small watershed of the low mountain and hilly region of Jilin Province,Northeast China.This study aims to elucidate the effects of soil and water conservation practices on soil conditions after the short-term implementation of practices.Soil samples were collected from five soil and water conservation sites(ER,FP,FR,SS,and VR)and two controls(BL and CT)to investigate their properties.To evaluate the influence of soil and water conservation practices on soil quality,an integrated quantitative index,soil quality index(QI),was developed to compare the soil quality under the different soil and water conservation practices.The results show that not all soil and water conservation practices can improve the soil conditions and not all soil properties,especially soil organic carbon(SOC),can be recovered under soil and water conservation practice in short-term.Moreover,the QI in the five soil and water conservation practices and two controls was in the following order:ER>VR>BL>FR>CT>SS>FP.ER exhibited a higher soil quality value on a slope scale.In the low mountain and hilly region of Northeast China,ER is a better choice than the conversion of farmlands to planted grasslands and woodlands early in the soil and water conservation program.

Characteristics of Sand Dune Pattern and Fluvial-aeolian Interaction in Horqin Sandy Land, Northeast Plain of China

The interaction between fluvial and aeolian processes can significantly change surface morphology of the Earth. Taking the Horqin Sandy Land as the research area and using Landsat series satellite remote sensing images, this study utilizes geomorphology and landscape ecology to monitor and analyze the aeolian geomorphology characteristics of the Horqin Sandy Land. Results show that the sand dunes of the Horqin Sandy Land are mainly distributed on alluvial plains along the banks of the mainstream and tributaries of the Western Liao River, and the sand dune types tend to simplify from west to east and from south to north. The aeolian geomorphology coverage tend to be decreasing in the past 40 years, with an average annual change rate of 0.31%. While the area of traveling dunes decreased, the area of fixed and semi-fixed dunes increased. The fractal dimensions of various types of sand dune have all remained relatively constant between 1.07 and 1.10, suggesting that they are experiencing a relatively stable evolutionary process. There is a complex interaction between fluvial and aeolian processes of the Horqin Sandy Land, which plays a central role in surface landscape molding. Sand dunes on both sides of different rivers on the Horqin Sandy Land present certain regularity and different characteristics in terms of morphology, developmental scale, and spatial pattern. There are six fluvial-aeolian interaction modes in this area: supply of sand sources by rivers for sand dune development, complete obstruction of dune migration by rivers, partial obstruction of dune migration by rivers, influence of river valleys on dune developmental types on both sides, influence of river valleys on dune developmental scale on both sides, and river diversion due to obstruction and forcing by sand dunes. This study deepens our understanding of the surface process mechanism of the interaction between fluvial and aeolian processes in semi-arid regions, and provides a basis for researches on regional landscape responses in the context of global environmental change.

Feathered sand ridges in the Kumtagh Desert and their position in the classification system

Feathered sand ridges in the northeastern Kumtagh Desert in China cover an area of 4016 km 2 and consist of crescent sand ridges and interridge tongue-shaped dunes.Differences in grain size,mineral composition and albedo between crescent sand ridges and tongue-shaped dunes,and between windward and leeward slopes of tongue-shaped dunes,result in their feathery appearance in aerial and satellite imagery.Measurements of the sand drift potential in the region show that the sand-moving wind for feathered sand ridges can be divided into three sectors;i.e.north-northeasterly,easterly and east-northeasterly sectors roughly corresponding to the southeast,northwest and southwest slip faces.Our findings suggests that the crescent sand ridges resulting from the connection of barchan dunes along the prevailing wind direction are longitudinal dune ridges rather than transverse ones.Tongue-shaped dunes and quasi-dune shapes have obvious distinctions and are new transverse dune types.According to McKee's dune shape classification,the feathered sand ridges are not a deformation dune type but a complex one.According to Wu's dune morphological and genetic classification,they are not dune ridges or compound dune ridges that form under the action of unidirectional winds or two winds intersecting at an acute angle,but are complex dune ridges that form under the action of three winds intersecting at an acute angle.