黑河绿洲坡面分异演化研究

对干旱区绿洲的物质和能量随坡面分异现象和规律的研究,有助于我们深刻了解不同类型绿洲形成和演化的自然背景和农业资源组合的特点,为农业生产的合理布局和农业自然资源的优化配置提供理论依据。以黑河流域绿洲为例,在综合分析影响绿洲坡面分异的气候、地质构造和地貌演化、地表水和地下水水文化学性质、土壤性状和水资源供应状况等自然地理要素基础上,将黑河绿洲划分为高位绿洲、中位绿洲和低位绿洲等不同类型。在此基础上,分析了黑河流域不同类型绿洲主要农作物气候适宜性随坡面的分异,为绿洲农业资源的优化配置提供了重要的理论依据。

Study on the Differentiation and the Evolution of Substance and Energy with the Slope Change in the Heihe Oases

The phenomenon and law studies of the substance and energy differentiation along with slope change in the oases of the arid region greatly conduce to better understanding the natural background of the inhomogeneity oases formation and evolution and the characteristic of agricultural resources combination. That can offer a theoretical basis of rational agricultural distribution and optimum disposition of natural resources. The oasis differentiation in the Heihe River Basin is obvious. On the basis of integrated analysis of the physical geographical elements of climate characteristic, geologic structure, geomorphologic evolution, surface and groundwater hydrochemistry character, soil properties, and water supply, the paper classifies the Heihe Oases into three types, that is, the higher position oasis, the middle position oasis and the lower position oasis. The higher position oasis lies to the diluvial fans of the north foot of the Qilian Mountain, the height is 1?400-2?200?m above sea level, the annual average temperature is 2.2℃-7.0℃in the district, and the annual precipitation and evaporation are 150-370?mm and 923-2?246?mm separately. This kind of oasis is more stable than the others. It is further subdivided into two types, that is, the higher cool oasis, which has high potentialities, and the higher temperate climate oasis, which is the cream of the oases in the Heihe River basin at present. The mid-position oasis lies to the alluvial plain of which the elevation is 1?100-1?400?m above sea level, annual average temperature 7.0-8.0℃, per annum precipitation 60-100?mm, and per annum evaporation 2?250-2?540?mm. The lower position oasis lies to the lacustrine plain and dry river delta, the height is about 900-1?100?m above sea level, the annual precipitation is only about 38?mm, however, the annual evaporation reaches the peak of 3?506?mm. This kind of oasis belongs to natural ones, and is unstable because of deficiency of water resources. Each type of oases has a certain combination of light, heat, water and soil, and has a certain oasis quality and suitable degree. Moreover, the paper has analysed the climate suitability of main crop differentiation with slope in very oases types of the Heihe valley. Every type of oasis possesses specific optimum combination, and every sort of crop has the most suitable planting region, and in accordance with these, the planting zone can be divided into five regions, that is, the most suitable, more suitable, suitable, little suitable and unsuitable planting regions respectively. That provides the important theoretical basis for optimum disposition of agricultural resources. Adjusting and distributing agricultural structure and energetically developing farm industry would suit measures to local conditions, so as to develop potential productive forces of photosynthetic, temperature, water and land resources to the full. Spring wheat, potatoes, flax, rapeseed and broad bean are suit to plant in the cool higher position oasis, spring wheat otherwise would be reduced the areas in the mid-position oasis due to the dry-hot wind.