长江河口九段沙上沙湿地芦苇与土壤之间营养元素的灰色关联分析

GRAY CORRELATION ANALYSIS ON NUTRIENT ELEMENTS BETWEEN PHRAGMITES AUSTRALIS PLANT AND SOIL IN THE UPPER SHOAL OF JIUDUANSHA WETLAND,THE YANGTZE RIVER ESTUARY

为探明生长季不同时期芦苇湿地生态系统植物与土壤之间营养元素的关系,利用灰色关联分析方法,对长江河口九段沙上沙芦苇湿地的芦苇营养元素吸收量与土壤营养元素含量之间的关联度进行了研究。结果表明:芦苇主要从0～15cm土壤吸取N元素,从15～40cm土壤获取P、K元素,而从40～60cm土壤吸收N、P、K元素量都较少。芦苇-土壤之间营养元素关联度排序为:4月为N>K>P;5月为P>K>N,6～8月为K>P>N;9～11月为N>K>P;12月为P>N>K。同一营养元素不同时期芦苇-土壤之间关联度也存在差异,芦苇与土壤营养元素N、P、K元素关联最密切时期分别出现在9、12与6月,均与上层土壤营养元素关联最密切。9、12与6月分别为芦苇-土壤之间N、P、K元素迁移、转化与循环的活跃时期,上层土壤是其活动相对重要的场所。芦苇生长过程中吸收土壤营养元素均存在时空差异,不同时期芦苇对不同深度土壤的营养元素吸收强度也不尽相同。芦苇地下部分不同部位与土壤中营养元素种类的关联度排序相同,而芦苇地上部分的排序则不同。

Gray correlation analysis method was applied to analyze the relation of nutrient elements between Phragmites australis and soil at the Phragmites australis wetland in the upper shoal of Jiuduansha wetland,the Yangtze river estuary in order to understand the relations between the absorbing content of the nutrient elements in plant growth progress and the content of nutrient elements of soil in the wetland ecosystem in different periods of the growing season.The results indicated that the absorption of nutrient elements by Phragmites australis showed time-spatial distribution characteristics in the process of plant growth.Phragmites australis mainly absorbed N in the depth of 0～15cm,P and K in the depth of 15～40 cm in soil profile,while it absorbed less in depth of 40～60cm in the soil profile.Association degree of nu-trient elements between plant and soil was in the order of N KP in April;P K N in May,KP N in June to August;NKP in September to November;PNK in December respectively.The association degree of same nutrient element between the plant and soil also was not same in the different growth period of the plant.The closest relationship of the nutrient elements N,P,K between plant and soil occurred in September,December and June separately,and the closest relationship of the nutrient element between the plant and soil appeared in the upper layer of soil.The active period for migration,trans-formation and cycling of nutrient elements K,N,P occurred in June,September and December respectively,and the upper layer of soil was an important place for nutrient element activity.There was obvious difference in time and space for the growth of Phragmites australis to use nutrient elements K,N,P in the soil,and there was also difference for Phragmites australis to absorb nutrient elements K,N,P in different depth of soil in different growing periods of the plant.The orders of association degree of nutrient elements between different modular of underground part of Phragmites australis and soil were same,but those of association degree of nutrient elements between different modular of aboveground part of Phrag-mites australis and soil were different.