天山北坡绿洲土地退化的时空变异

Temporal and spatial variation of land degradation in alluvial oasis at northern slope of Tianshan Mountain

以天山北坡三工河流域农业绿洲?阜北农场为例,运用遥感与GIS技术,结合地统计学理论,对研究区1983—2005年间景观结构与土壤表层(0～20cm)土地退化时空变异特征进行了研究.结果表明:人为活动增加了区域绿洲景观破碎化和多样性,区域景观改变的人为影响程度加剧是造成景观多样性和景观破碎化的主要动因;1983—2005年间,区域土地退化面积减少26·69%,土地退化程度较高的区域主要分布在北部靠近沙漠区,沿沙漠区向绿洲内部土地退化的程度降低.灰漠土退化程度明显高于盐土和潮土,并且土地质量差的区域,土地退化程度逐渐减轻,有65·38%的土地质量提高;而土地质量好的区域土地退化程度加重,有33·38%的土地发生退化.

Taking the Fubei Farm, a farming oasis of Sangong River watershed at the northern slope of Tianshan Mountain as study area, and by the methods of geostatistics, GIS and RS, this paper studied the temporal and spatial variation of land degradation in topsoil （0-20 cm） and its relationship with landscape structure. The results showed that in this oasis, human activity was the key factor resulting in the increase of landscape fragmentation and diversity. From 1983 to 2005, the land degradation area decreased by 26. 69% , and the degradation degree was higher in the regions adjacent to desert than in those further inside the oasis. Gray desert soil was degraded much more seriously than saline soft and aquic soil. The regions of poor land quality had an alleviated degradation, with 65.38% of land area improved, while those of good land quality had an aggravated degradation, with 33.38% of land area degraded.