排序方式： 共有6条查询结果，搜索用时 15 毫秒
1
1.
Ningxia Hui Autonomous Region is situated in 30;14′–30;14′ and 30;33′–30;39′.Though its area. Is only 67000km2, it has many various ecosystem categories. The vegetation is the core of the ecosystem, so it is very important to research. The vegetation in Ningxia is the combination of many various vegetation types which have certain egularity of ecogeographical distribution. The zonal vegetation types in Ningxia arc the semi-desert, the steppe and the meadow-steppe from north to south. And there are the spectrums of the vertical belts of the vegetation in Helan mountain and Lupan mountain. There are also many intrazonal vegetation types—the saline-meadow, the grass-swamp, the salt vegetation, etc. Every vegetation type exists many various plant communities. And each vegetation type or plant community can reflect the comprehensive ecological factors. According to the regularity, we may put forward a principle of plan of the "Sanbei’(northeast, north and northwest China)shelter-forest in Ningxia:l. It is suitable to establish the scrub belts in Ningxia. In the semi-desert, the steppe, the meadow-steppe and the grass-tuft, the soil erosion on the slopes may be controled by the scrub belts following contour-line and the wind-sand-harm on the plateau plain may be prevented by the scrub networks; 2. To plant the shrubs, the semi-shrubs and the therophytes is suitable for fixing the sanddrift; 3. It isn’t difficult to plant the shelter-forest in the irrigation farmland. But it is very important to choose the tree species adapting various soil; 4. All of the forest and the scrub in the mountains must be closed and tended. The mixed-forest may be expanded on the meadow slope. 相似文献
2.
3.
4.
经国家农委农业自然资源和农业区划委员会批准,植被方面1980年进行新藏青甘交界地区的补充考察。中国百万分之一植被图植被区划编辑委员会委托中国科学院新疆生物土壤沙漠研究所主办这一考察工作。这一工作得到新疆农委、中国科学院新疆分院的关怀,在考察过程中并得到所经过的州、县有关领导机关的支持。新藏青甘交界地区植被考察队由八人组成,于7-8月进行了野外考察。这次考察由乌鲁木齐出发,经库尔勒、若(?)等州 相似文献
5.
6.
1