我国西北干旱区的荒漠化过程及其空间分异规律

我国西北干旱区的荒漠化可以归结为荒漠的荒漠化和绿洲的荒漠化两种类型。其中,荒漠的荒漠化主要表现为沙漠化,主要发生于土质荒漠和沙质荒漠。土质荒漠沙漠化的最终结果将由土质荒漠演变为沙质荒漠或砾质荒漠或风蚀劣地,沙质荒漠的沙漠化是由固定、半固定沙质荒漠演变为流动、半流动沙质荒漠的过程,其最终结果是形成流动沙质荒漠。绿洲的荒漠化主要包括绿洲的干旱化、沙漠化和盐渍化3种类型。其中,干旱化常导致绿洲植被的衰退和死亡,致使绿洲萎缩,其边缘地带常和沙漠化叠加,导致流沙对绿洲的入侵。如果绿洲水源完全断绝,其绿洲将会消失,最终演变为沙质荒漠或风蚀劣地。绿洲盐渍化主要源于过度灌溉导致地下水位抬升,下层土壤盐分聚集地表所致,其结果是形成盐渍化绿洲。我国西北地区土质荒漠的荒漠化主要发生于内蒙古阿拉善地区的东部、天山南麓冲积扇上的土质荒漠带,以及准噶尔盆地北侧的荒漠草原带;沙质荒漠的荒漠化主要发生于准噶尔盆地的古尔班通古特沙漠。绿洲干旱化和沙漠化以甘肃民勤最为典型,而绿洲的盐渍化主要发生于新疆阿克苏、喀什地区一带。

Desertification Process and Its Spatial Differentiation in Arid Areas of Northwest China

Land desertification in arid areas of northwest China could be classified as two types: desert desertification and oasis desertification.Desert desertification presents mostly aeolian desertification,which occurs mainly in terrene desert and sandy desert.As final result of desertification,terrene desert turns into sandy desert,gravel desert or aeolian land.Desertification of sandy desert is a process that fixed and semi-fixed desert turn into mobile or semi-mobile desert,which results finally in formation o...