摘要
以甘肃民勤沙区为研究区域 ,分别采集了不同地貌部位和不同植被类型下的土壤结皮 ,并对其理化性质进行了初步分析。从结皮土壤的机械组成、土壤盐分、土壤养分、土壤阳离子交换量等方面来看 ,丘间地状况都明显要优于灌丛沙包。这可能与丘间地地形低洼 ,有利于土壤物质汇聚 ,以及其接受的大气降尘远较灌丛沙包为多有关。对于灌丛沙包来讲 ,白刺沙包在理化性质上 ,其状况要优于红柳结皮和梭梭结皮 ,这主要与其对环境的适应性及其所处的演替阶段有关。从目前的植被演替情况来看 ,白刺是当地的顶极种群 ,最适应环境 ,因此结皮发育状况也好 ;红柳目前已经处于极度退化进程中 ,而梭梭为人工植被 ,人工植被因在演替阶段中不起决定作用 ,故理化性质较差。另外从该研究工作还可以看出 ,对白刺植被采取围封措施之后 ,可以显著地促进结皮的生长发育 ,提高结皮中的有机质、全 N、全 P、速效 N等养分以及 Ca CO3含量。
Taking the Minqin county as the research region, the sand soil crust sample in different geomorphic site and plant community were collected, and its physical and chemical characteristics were analyzed, in which the soil mechanical composition, soluble salt, soil nutrient elements, organic matter, Ph value, CEC and CaCO 3 content were included. The result showed that whether in the sand dune or the takyr soil, the crust soil mechanical composition is mostly composed by sand (1~0.05mm) and coarse silt particle (0.05～0.01mm). The total salinity is the highest in the takyr soil crust than in any other soil crust, but in the shrub sand dune, the physical soil crust and the Tamarix ramosissima soil crust is highest, and changes of the total cation and anion has the same changing trend. The Nitraria tangutorum soil crust and the takyr soil crust have the higher CEC, and this shows that they have the higher ability in keeping soil fertility. The pH value all is bigger than 7 in different soil crust. The CaCO 3 content in takyr soil is the highest, but in shrub sand dune the situation is that closed Nitraria tangutorum > Nature Nitraria tangutorum community > Tamarix ramosissima community >artificial Haloxylon ammodendron community. In the soil crust nutrient aspects, Nitraria has the highest fertilizer and the artificial Haloxylon ammodendron community has the lowest fertilizer. If we set the top soil of the shifting sand dune and physical soil crust as a background, we can found that the content of Total N, Total P, rapidly available N and rapidly available P is decreased and rapidly available is increased after crust developing. For the integrated view, the result shows that the physical and chemical characteristics of soil crust is better in the takyr soil and Nitraria tangutorum, especially in the closed Nitraria tangutorum. There are three reasons result from above conclusions. The first one is that the takyr soil has the lower microlandform which conduce to rain water and soil matter to congregated in it. The second one is that the takyr soil has a bigger open space than that of shrub sand dune, so it can receive more sand dust matter which is very important for the soil crust development. The third one is the adaptability of plant to environment and its succession process. Under present situation, Nitraria tangutorum is the climax species in this region, and Tamarix ramosissima is in the degenerate stage, so the soil crust developing state under the former plant is better than that of the latter. From our research, we found that the Nitraria tangutorum soil crust develop better after enclosed, in which the organic matter, total N, Total P and rapidly available nutrient were enhanced rapidly. Because the degradation of vegetation and soil is very serious in desert-oasis region, the artificial close measurement is a availability way to combat this process.
出处
《生态学报》
CAS
CSCD
北大核心
2003年第7期1442-1448,共7页
Acta Ecologica Sinica
基金
国家"十五"科技攻资助关项目 ( 2 0 0 2 BA5 1 7A0 9)
国家自然科学基金资助项目 ( 3 0 0 70 60 1
3 9990 490 )~~
关键词
绿洲荒漠区
土壤结皮
理化性质
民勤
甘肃
desert-oasis region
soil crust
physical and chemical characteristics
Minqin County
Gansu Province
