| 张淑杰,郭亚琳,樊敏,王青.藏-羌聚落交错区耕地坡谱与信息熵变化特征[J].干旱地区农业研究,2018,36(4):239~245 |
| 藏-羌聚落交错区耕地坡谱与信息熵变化特征 |
| The variation characteristics on slope spectrum and information entropy of cultivated land in the crossing zone of Tibetan-Qiang settlement |
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| DOI：10.7606/j.issn.1000-7601.2018.04.34 |
| 中文关键词: 坡谱 信息熵 耕地 藏-羌聚落交错区 |
| 英文关键词:slope spectrum information entropy cultivated land Tibetan-Qiang settlement crossing zone |
| 基金项目:国家科技支撑计划(2015BAC05B04);四川省重点研发项目“岷江上游藏区耕地非农化过程与风险阈值”（2017SZ0086） |
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| 中文摘要: |
| 以藏-羌聚落交错区为研究单元，提取该地区1999、2009年和2014年耕地空间信息，通过信息图谱与信息熵定量刻画交错区耕地的坡度分异特征，阐明坡耕地利用的合理程度。结果表明：1999-2014年间，藏-羌聚落交错区耕地总量下降显著，≥24°的耕地坡谱段递减明显，陡坡耕地耕作率由1999年的83.67%到2009年的71.97%再到2014年的55.03%，发生明显下降；坡度≤14°的耕地坡谱段呈现上升趋势，缓坡耕作率三年分别为16.33%，28.03%和44.97%，说明交错区耕地利用逐渐向坡度缓和的方向移动，缓坡耕地将逐步成为当地的农作物集中分布区。在退耕还林和5·12地震及其次生地质灾害的双重影响下，藏-羌聚落交错区耕地信息熵由1999年的1.253增加为2009年的1.515，进一步增至1.707，呈逐渐增加的态势，这表明缓坡耕地与陡坡耕地的占比差距缩小，耕地在不同分级坡段间的分布趋于均匀，利于当地水土保持。 |
| 英文摘要: |
| The study takes the Tibetan-Qiang settlement as the research unit and extracts the local spatial information of the cultivated land of the zone in 1999, 2009 and 2014, and quantifies the slope differentiation characteristics of the cultivated lands through geo-info spectrum and information entropy technologies to clarify the reasonability of cultivated land utilization system in the Tibetan-Qiang crossing zone across the upper reaches of Min River. The results reveal that: (1) during the three study periods (1999~2014), the total amount of cultivated land decreased significantly and the slope spectrum curves of cultivated land descended significantly when the slope is over than or equal to 24°, meanwhile the cultivation rate of steep cultivated slope land also has dropped dramatically from 83.67% in 1999 to 71.97% in 2009 and to 55.03% in 2014. However, the spectrum curves in the range of the slope less than or equal to 14° showed an ascending variation trend and the rate of gentle slope cultivation is 16.33%, 28.03% and 44.97% for 1999,2009 and 2014, respectively, indicating that the distribution of cultivated land moved gradually toward the regions with gentle cultivated slope land and it will gradually become the local concentrated distribution area of crops. (2) Under the influences of the implementation of the Grain for Green Project, the occurrence of 5·12 earthquake and the secondary geological hazards derived from the earthquake, the information entropy of slope spectrum for cultivated land increased from 1.253 in 1999 to 1.515 in 2009, and further reached 1.707 in 2014, showing an increasing trend in the Tibetan-Qiang settlement crossing zone. Therefore, the gap between area percentage of gentle cultivated slope land and area percentage of steep cultivated slope land has narrowed. It suggests that the allocation of cultivated lands in different hierarchical slope sections tends to be uniform, which is conducive to local conservation of water and soil. The research results can provide the basis for the reasonable planning, utilization and scientific management of cultivated lands in the crossing zone of Tibetan-Qiang settlement across the Upper Reaches of Min River. |
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