不同放牧梯度上典型草原植物碳氮磷化学计量特征

Stoichiometric Characteristics of CNP in Typical Steppe Plant at Different Grazing Gradients

为揭示放牧压力对草原植物适应性生长的影响规律和生态化学计量特征,对克鲁伦河流域的典型草原不同放牧梯度上的植物优势种和共有种的碳(C)、氮(N)、磷(P)元素进行了测定分析,结果表明:不同物种间C/N和N/P的最高值和最低值出现的放牧区域也不同,同一物种间在同一放牧区域中的C/N值和N/P值也存在差异。共有种克氏针茅养分含量大小依次为C>N>P,其中全C含量,地上部分和地下部分分布规律均为中牧>轻牧>重牧,全N含量地上部分和地下部分分布规律为轻牧>中牧>重牧,全P含量地上部分和地下部分分布规律为重牧>中牧>轻牧。随着放牧强度的加剧,共有种克氏针茅的C/N值先增加后减少,在中牧放牧梯度下含量达到最大值;N/P值逐渐减小,重牧区达到最小值。

To reveal the influence of grazing pressure on plant＇s adaptable growth and stoichiometric charac teristics of steppe plants,the article conducts a survey to determine the carbon （C） ,nitrogen （N） and phosphorus （P） in the dominant and common species in Kherlen basin of typical steppe with different grazing gradients. The results show that the different species＇ highest and lowest values of C/N and N/P appear in different gazing area,while the values of C/N and the N/P of the same species in the same grazing area are also different. The nutrient content of Stipa krylovii is in the order of C〉N〉P in the common species,in which the content of C of the aboveground and underground parts are in the order of moderate grazing〉light grazing〉heavy grazing; the content of N of the aboveground and underground parts are in the order of light grazing〉 moderate grazing 〉heavy grazing; the content of P of the aboveground and underground parts are in the order of heavy grazing〉 moderate grazing〉light grazing. The C/N value of S. krylovii in common species increases first and then decreases as the grazing intensity increases, which obtains the maximum value at the moderate grazing gradient; the N/P value decreases gradually and gets the minimum value at the heavy grazing gradient.