| Effects of cropping patterns on surface thermal landscape in gravel-sand mulching field |
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| DOI：10.7606/j.issn.1000-7601.2016.01.41 |
| Key Words: gravel-mulched land cropping patterns land surface temperature landscape pattern ecological environment |
| Author Name | Affiliation | | HOU Jing | Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University/ Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China of Ministry of Education, Ningxia University, Yinchuan, Ningxia 750021, China | | DU Ling-tong | Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University/ Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China of Ministry of Education, Ningxia University, Yinchuan, Ningxia 750021, China | | ZHANG Xue-jian | Ningxia Academy of Agriculture and Forestry Sciences, Yinchuan, Ningxia 750021, China |
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| Abstract: |
| The method of gravel-mulched moisture conservation has been adopted to a large extent in the Xiangshan region of Ningxia for the past few years. Covered with gravel and coarse sand, land surface was affected obviously in soil temperature. It was of importance to quantify the characteristics of thermal landscape for evaluating regional ecologic security and thereby serving for agricultural production. Based on Landsat Enhanced Thematic Mapper Plus (ETM+) thermal images, land surface temperature was retrieved around Xiangshan region. Differences of thermal parameters were calculated, followed by landscape metrics to analyze dynamic changes of thermal field landscape pattern. The results showed that gravel-mulched land topped the list for land surface temperature and heat field variation index around Xiangshan region in Ningxia, followed by unutilized land. Moreover, land surface temperature of grassland, farmland and forestland was lower. In the past ten years, thermal field exhibited an evolving trend: high-grde thermal patches increased first and then decreased, and landscape changed from simplicity to complexity and finally to simplicity. From 2004 to 2009, the patch amount and density increased significantly, thermal landscape became more fragmented. The dominance of high-grade thermal landscape patch was upgraded obviously, and the patch shape trended to complex. Regional heat island effect was enhanced significantly because of the conversion of a great number of patches from low-grade to high-grad. From 2009 to 2013, however, thermal landscape pattern showed an opposite tendency in comparison with that between 2004 and 2009. The changes of planting structure were the main causes of thermal landscape pattern evolution. The area of gravel-mulched land expanded rapidly around Xiangshan region in Ningxia, the gravel-mulched land changed from fragmentation to concentration before 2009. Changing the properties of underlying surface on a large scale resulted in land surface temperature rising. From 2009 to 2003, although the area of gravel-mulched land kept on expanding, the vegetation coverage increased and the area proportion of high-grade thermal patches started to decline due to the adjustment of planting structure and the implementation of jujube-melon intercropping. |
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