不同土地利用方式下土壤碳氮磷化学计量特征

Ecological Stoichiometry of Soil Carbon,Nitrogen and Phosphorus Under Different Land Use Patterns

【目的】本研究以达拉特旗南部地区不同土地利用方式下的土壤为研究对象,分析不同植被下土壤有机碳(SOC)、全氮(TN)、全磷(TP)含量及其生态化学计量比的特征以及它们之间的相互关系,以揭示同一环境条件不同土地利用方式对土壤营养元素的影响与反馈能力,以期为研究区土地的合理利用提供理论依据。【方法】采用常规测量方法测定林地、草地、耕地、撂荒地不同深度土层的碳氮磷含量。【结果】①研究区不同土地利用方式下0~80 cm土层范围内土壤SOC和TN含量随土层深度的增加而降低,且表现为乔木林地>灌木林地>草地>农地>撂荒地。②研究区不同土地利用方式下土壤C/N变异系数最小属弱变异,受土地利用方式影响较小;C/P、N/P属中等变异,受土地利用方式影响较大,研究区植被的生长主要受氮素的营养限制。③研究区土壤C/N、C/P比值主要受SOC含量的影响,N/P主要受SOC和TN含量的影响。【结论】不同利用方式下各元素含量在土壤表层呈现出不同程度的差异性,土壤SOC、TN较TP受到利用方式的影响更为明显。

【Objective】This study used soils under different land use patterns in the southern part of Dalate Banner as the research object to analyze the contents of soil organic carbon(SOC),total nitrogen(TN)and total phosphorus(TP)under different vegetations.The characteristics of ecological stoichiometry and their interrelationships were used to reveal the influence and feedback ability of soil nutrient elements under different land use patterns under the same environmental conditions,in order to provide a theoretical basis for the rational use of land in the study area.【Method】The carbon,nitrogen and phosphorus contents in different depths of forest land,grassland,cultivated land and abandoned land were determined by routine measurement methods.【Result】(i)The soil SOC and TN content in the 0-80 cm soil layer decreased with the increase of soil depth under different land use patterns in the study area,and it was expressed as arbor forest land>shrub land>grassland>agricultural land>wasteland.(ii)The soil C/N coefficient of variation was weakly mutated under different land use patterns in the study area,and was less affected by land use;C/P and N/P were moderately mutated,which were greatly affected by land use patterns.The growth of vegetation was mainly limited by the nutrient of nitrogen.(iii)The soil C/N and C/P ratios in the study area were mainly affected by SOC content,and N/P was mainly affected by SOC and TN content.【Conclusion】The content of each element in different utilization modes showed different degrees of difference in the soil surface.The soil SOC and TN were more obvious than the TP utilization mode.