The Opening-up Wasteland In The Middle Reaches Of The Yellow River And The Deterioration Of Natural Environment In The Middle-lower Reaches Of The Yellow River

Ming dynasty was in the "Little Ice Age" in which the earth was becoming cold. The temperature of the earth declined on the whole, the climate became dry, the natural environment tended to dry and cold. The middle reaches of the Yellow River was fragile in ecology. Influnced by the whole dry and cold climate, little environment was inclined to degenerate. However, the dynamic opening-up wasteland in "Jiubian" area, owing to exceeding reclaimation, surpassed the bearing capacity of the environment, leading to accelerate further the speed of the environmental deterioration. Therefore, there appeared such phenomena as the land degenerating, the lake silting and deserting, natural calamity occurring frequently in the middle-lower reaches of the Yellow River.The thesis will fall into three parts:First: Reappearing the details of opening-up wasteland in the middle reaches of the Yellow River, analyzing the historical background and favorable policies of opening-up wasteland, introducing the contemparory conditions of reclaimation respectively from troops, masses and commercials engaged in farming as well as garrisonduties.Second: Analyzing two factors: the climate becoming cold on the whole and humanity reclaiming excessively which led to the deterioration of natural environment in the middle-lower reaches of the Yellow River.Third: The deterioration of natural environment in the middle-lower reaches of the Yellow River. Expounding the above phenomenon from three aspects: the degeneration of the land, the silt and waste of the lake, the frequent occurrence of natural calamity.Through studying the opening-up wasteland in the middle reaches of the Yellow River as well as its influence on the natural environment in the area of the middle-lower reaches, the thesis will try to provide enlightments for the western opening-up of china.