| 关中平原人工林地的干层及其成因 |
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| 引用本文： | 赵景波,孙桂贞,岳应利,陈宝群.关中平原人工林地的干层及其成因[J].地理研究,2007,26(4):763-772. |
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| 作者姓名： | 赵景波 孙桂贞 岳应利 陈宝群 |
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| 作者单位： | 1. 陕西师范大学地理系,西安,710062;中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安,710075
2. 陕西师范大学地理系,西安,710062 |
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| 基金项目： | 国际地质对比计划项目（IGCP448）;国家自然科学基金项目（400571004）;中国科学院地球环境研究所黄土与第四纪地质国家重点实验室项目（SKLLQG0504）. |
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| 摘 要： | 根据关中平原人工林地土层含水量测定,研究了0~6m土层含水量的变化、干层特点、分布和形成原因。分析得出,在年降水量小于600mm的中国西北地区,人工林地的干层是普遍发育的自然现象,干层形成的主要原因是降水量少决定的重力-毛管水带厚度明显小于4m,引起干层发育的直接作用的水分因素是薄膜水带埋藏深度小、含水量低、运移速度缓慢,而乔木树种的耗水则是引起干层发育的植物因子。关中和黄土高原重力-毛管水带与薄膜水带分布深度很清楚地指示,该区的土壤干层主要是自然原因决定的,不论是人工林还是自然林,厚层黄土上的中龄林一般都有干层发育。在干层发育弱的地区可以造林,在发育强的地区则不适宜造林。
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| 关 键 词： | 关中地区 人工林 干层分布 重力水 薄膜水 生态环境 |
| 文章编号： | 1000-0585（2007）04-0763-10 |
| 收稿时间： | 6/3/2006 12:00:00 AM |
| 修稿时间： | 2006-06-032006-10-25 |
Research of dried earth layer and its formation in the artificial forest land of Guanzhong Plain |
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| ZHAO Jing-bo,SUN Gui-zhen,YUE Ying-li,CHEN Bao-qun.Research of dried earth layer and its formation in the artificial forest land of Guanzhong Plain[J].Geographical Research,2007,26(4):763-772. |
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| Authors: | ZHAO Jing-bo SUN Gui-zhen YUE Ying-li CHEN Bao-qun |
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| Institution: | 1. Department of Geography, Shaanxi Normal University, Xi’an 710062,China;
2. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS, Xi’an 710075, China |
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| Abstract: | Moisture content change and characteristic,distribution,formation reason of dried earth layer under artificial forest land and lawn ranging 0~6m depth in Guanzhong Plain were studied in this article by drying-weight method.The aim of the research is to verify the distribution scope of dried earth layer in the south of the Loess Plateau and the reason of it,and to provide scientific basis for the prevention and control of dried earth layer.Experiment results show that the average earth moisture content is 8.4% between 2 and 4m of 10 age apple trees,the average earth moisture content is 9.0% between 2 and 4m of 12 age phoenix trees in Xianyang.The average earth moisture content is between 9.3% and 9.5% between 1.8~3.6m of 12 age phoenix and poplar trees in Lantian.The average earth moisture content is 9.2% between 2 and 3.5m of 15 age apple trees in Wujiafen,and there is formation of dried earth layer between 2 and 3.5m.There is obvious formation of chronic dried earth layer in artificial forest land at Xiekou of Lintong and Weiqu of Chang'an.The average earth moisture content is more than 12% below 4m of the middle age artificial forest land,which indicates that the dried earth layer doesn't extend to the layer below 4m.The average earth moisture content is more than 12% below 2m of 6 age and 4 age apple trees land,and there is no formation of dried earth layer.According to the computation of CaCO3 migration depth model,under 600mm annual precipitation condition in Guanzhong Plain,the migration depth of gravity water is less than 4m,which indicates that the dried earth layer in this area is chronic.The changes of the moisture content of the artificial forest land show that the dried earth layer is distributed extensively on the Loess Plateau,and the south boundary of it has reached the northern foot of the Qinling Mountains.In Northwest China,where annual precipitation is less than 600mm,the dried earth layer in the artificial forest land is a universal natural phenomenon.The formation reason of the dried earth layer is that the gravity-capillary zone depth,which is determined by precipitation,is obviously smaller than 2 m.The direct action of water factor of dried earth layer is that the buried depth of the zone is small and the water movement velocity is slow,while the high water consumption tree species is the vegetation factor of it.It is clearly shown that the depth of the gravity water and the capillary water in Guanzhong Plain is the main natural factor for the formation of the dried earth layers.Whether the artificial forest or natural forest,the dried layers generally develop in the middle age forest land.The formation of the dried layer doesn't mean that the forests can not develop in this area,but they cannot develop well.Trees can be planted in areas where dried earth layer developed poorly,but they are not suitable to be planted in areas where dried earth layer developed intensely. |
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| Keywords: | Guanzhong area artificial forest distribution of dried earth layer gravity water capillary water ecological environment |
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