【摘要】 针对松嫩盐碱草地上的几种主要植物 ,以植物地上生物量和总和优势度 ( SDR)为土壤营养位效能指标 ,分别从多项土壤因子综合、可溶盐含量、总碱度、Na+含量、有机质含量、全氮含量角度进行了土壤营养位分析。讨论了松嫩盐碱草地植物种群分布格局与土壤营养的关系 ,指出松嫩盐碱草地植物种群分布格局的形成是可溶盐含量、总碱度、Na+ 含量、有机质含量、全氮含量 5项主要土壤因子综合作用的结果 ,对于各植物种群土壤营养位的分化结果而言 ,没有一项土壤因子是起决定性作用的更多还原

【Abstract】 Plant growth and species compositions are affected by the soil properties in semiarid grassland.Therefore studying the relationships between plant distributions and soil nutrient characteristics are important to understand the spatial patterns and process of plants in ecosystems of semiarid grassland.In this paper we use soil nutrient field analysis(SNFA)method to study the relations of plant overground biomass(POB)and summed dominance ratio(SDR)with 13 soil factors,i.e.,organic materials,total N,total P,total K,total Na,total Ca,total Mg,total alkalinity (CO 2- 3 +HCO - 3),soluble salt,K +,and Na + contents,also soil pH and moisture,respectively,in Zhaozhou Grassland Experiment Station(124°47′～124°50′E,45°46′~45°48′N),one parts of the Songnen alkaline grassland of the Northeast China. On June of 1995,according to the species compositions and growth status,15 types were selected from the site of alkali patches where has no plants growing to the site of grassplots where has the abundant plant species.We sampled 5 quadrates in each type (total 75 quadrates) and measured plant height,cover degrees,densities,overground biomass at each quadrates for each types.We also selected 5 soil samples from 0～10cm below ground at each quadrates.Every 5 quadrate data were calculated to be represented as means for each types.The 13 soil factors were analyzed by principal component analysis(PCA),the first principal component as soil nutrients is X-axis,and the relative overground biomass or SDR,reflecting the effciency of soil nutrient field(SNF),is Y-axis,respectively.Based on the plant importance in the Songnen alkaline grassland,all 32 plant species were classified into 4 plant groups,i.e.,Aneurolepidium chinense,Puccinellia tenuiflora,Suaeda spp.(including 3 Seepweed species and 1 sagebrush species),and “other”(including 26 plant species),and the soil nutrient fields(SNF)of this 4 groups were calculated by the methods of Yan et al [12].For comparing the differences among the 4 groups,we used 4 variables,SNF center points,SNF breadths,SNF volumes,and SNF overlaps,all of which were the relative values,to do analysis in the research.SNF center point is the relative positions of coordinates,SNF breadth is the breadth of one group to total breadth ratios,SNF volume is the volume of one group to total volume ratios,and SNF overlap is the ratio of one group overlap to total overlap,respectively.The total SNF breadth is total length of X-axis,and was calculated by PCA using 13 soil factors from 15 types.The total SNF volume is the integration values of total SNF breadth when the functions f(x) of SNF is at the maximum efficiency of the SNF,i.e.,the product of maximum effciency and total SNF breadth at data analysis. Both POB and SDR have the similar results to express the plant efficiencies of SNF in 4 groups.The results show that the functions of SNF of Suaeda spp.,P.tenuiflora and A.chinense are all single-peak curves,which indicate that there are the optimal soil nutrient condition at the field in Songnen grassland.The optimal position at X-axis is the SNF center point,and also the same of the corresponding value to the single-peak curve at X-axis.The plant growth and distributions were limited heavily away from this optimal soil nutrient position on the curves due to poor soil conditions and plant interspecific competitions.Such as Suaeda spp,P.tenuiflora and A.chinense,they are mainly restricted by soil nutrients in right side of curves,and by interspecific competitions in left side of curves at X-axis. When the efficiencies of SNF is characterized by POB,the maximum breadth of SNF is A.chinense,while P.tenuiflora close to it,but both breadths of them are broader than that of both “other” and Suaeda spp.,This means that A.chinense,and P.tenuiflora have a adaptability of soil condition in a larger ranges.As to the volume of SNF,“other” is the largest one,P.tenuiflora is little lower to “other” and closed to A.chinense,the smallest one is Suaeda spp.Although both P.tenuiflora and A.chinense have larger breadt更多还原