克氏针茅草原土壤生态化学计量特征对放牧强度的响应

生态化学计量学是研究生态系统中各元素间平衡的科学，对于探究土壤有机碳（C）、全氮（N）、全磷（P）元素循环以及土壤养分限制状况具有重要意义。为了解克氏针茅（Stipa kirschnii）草原土壤生态化学计量特征，以内蒙古克氏针茅草原区为研究对象，在不同放牧强度草场进行采样分析。结果表明：随着放牧强度的增加，C、P含量先降低后升高，N含量先升高后降低；土壤C/N先降低后升高、C/P逐渐升高、N/P先升高后降低。C/N随着放牧强度的增加与有机碳相关性逐渐增大、与全氮的相关性逐渐减小；轻牧区的C/P受有机碳作用有所增强；中牧区N/P受全氮作用增强。C/N主要限制因素是有机碳含量，C/P和N/P主要限制因素是全磷含量。不同放牧强度会影响土壤化学计量比与其他物质的关系，也会改变土壤化学计量比各制约因素的强度。

Response of soil ecological stoichiometric characteristics to grazing intensity in Stipa kirschnii grassland

Ecochemometrics aims to study the balance of various elements in an ecosystem, which is of great significance to the exploration of soil organic carbon(C), total nitrogen(N), total phosphorus(P) element cycle, and soil nutrient limitation. In order to understand the soil ecological stoichiometric characteristics of Stipa kirschnii grassland, this paper took Stipa kirschnii grassland in Inner Mongolia as the research object, and conducted sampling analysis in pastures with different grazing intensities. The results showed that with the increase of grazing intensity, the content of C and P first decreased and then increased, and the content of N first increased and then decreased. Soil C/N first decreased and then increased, C/P gradually increased, and N/P first increased and then decreased. With the increase of grazing intensity, the correlation between C/N and organic carbon increased gradually, while the correlation between C/N and total nitrogen decreased gradually. The C/P of light pastoral area was enhanced by organic carbon. N/P in the middle pastoral area was enhanced by total nitrogen. The main limiting factor of C/N is organic carbon content, while the main limiting factor of C/P and N/P is total phosphorus content. Different grazing intensities will affect the relationship between soil stoichiometric ratio and other substances, and also change the strength of each limiting factor of soil stoichiometric ratio.