放牧对荒漠草原土壤和优势植物生态化学计量特征的影响  

Effects of grazing on ecological stoichiometry of soil and dominant plants in desert grassland

作　　者：安钰[1] 安慧[2] 李生兵 AN Yu;AN Hui;LI Sheng-bing(Institute of Desertification Control,Ningxia Academy of Agriculture and Forestry Sciences,Yinchuan 750002,China;Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China,Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China,Ningxia University,Yinchuan 750021,China;Yanchi Science&Technology Bureau,Yanchi 751500,China)

机构地区：[1]宁夏农林科学院荒漠化治理研究所,宁夏银川750002 [2]宁夏大学西北土地退化与生态恢复省部共建国家重点实验室培育基地,西北退化生态系统恢复与重建教育部重点实验室,宁夏银川750021 [3]盐池县科学技术局,宁夏盐池751500

出　　处：《草业学报》2018年第12期94-102,共9页Acta Prataculturae Sinica

基　　金：国家自然科学基金(31260125);宁夏科技支撑计划项目(2015BY025)资助。

摘　　要：以宁夏荒漠草原土壤和优势植物为研究对象,分析放牧对荒漠草原生态系统土壤和植物C、N、P化学计量学特征的影响机制。结果表明,土壤C、C∶N、C∶P随着放牧强度的增加呈下降趋势,P呈增加趋势,而N及N∶P呈先增加后下降趋势。不同优势植物N含量对放牧强度的响应存在一定的差异,中度和重度放牧区甘草、砂珍棘豆、山苦荬、牛心朴子N含量明显低于轻度和围封禁牧N含量,牛枝子、短花针茅、中亚白草、刺叶柄棘豆、虫实、猪毛菜、乳浆大戟、骆驼蓬N含量明显高于轻度和围封禁牧N含量,表明适度放牧会显著增加某些物种的N含量;13种优势植物C∶N和C∶P在不同放牧强度下均表现为与N、P的规律相反,且不同优势植物N∶P对放牧强度的响应也存在一定的分异性。优势植物P、C∶P与土壤P、C∶P呈显著正相关,而C、N、C∶N和N∶P与土壤C、N、C∶N和N∶P无显著相关性,说明植物叶片的化学计量特征并非是由土壤养分含量特征直接决定的,而更多是受植物自身遗传特性的影响,体现了荒漠草原优势植物对极端环境具有相对稳定的适应能力。To determine the effect of grazing intensity on ecological stoichiometry characteristics,we evaluated the carbon(C),nitrogen(N),and phosphorus(P)contents in soil and dominant plants in desert grassland of Ningxia under different grazing intensities.The results showed that the C content and ratios of C∶N and C∶P in soil decreased with increasing grazing intensity,while the P content increased,and the N content and N∶P ratio decreased after an initial increase.The N contents in different dominant plants showed different responses to grazing intensity.The N contents in Glycyrrhiza uralensis,Oxytropis racemosa,Ixeris chinensis,and Cynanchum komarovii were significantly lower under moderate and heavy grazing intensities than under light grazing intensity and no grazing.The N contents in Lespedeza potaninii,Stipa breviflora,Pennisetum centrasiaticum,Oxytropis aciphylla,Corispermum hyssopifolium,Salsola collina,Euphorbia esula,and Peganum harmala were significantly higher under moderate and heavy grazing intensities than under light grazing intensity and no grazing.These results indicated that an appropriate grazing intensity could significantly increase the N content of some species.The trends in C∶N and C∶P ratios in the 13 dominant plants were opposite to the trends in N and P contents under different grazing intensities,and the effect of grazing on the N∶P ratio differed among the different dominant plant species.The P content and C∶P ratio of dominant plants were significantly positively correlated with the P content and C∶P ratio of soil,but there was no correlation between the C and N contents and the C∶N and N∶P ratios in dominant plants and those in soil.These findings indicated that the stoichiometric characteristics of plants were affected by the genetic characteristics of plants,and not directly determined by soil nutrient contents.This helps to explain why dominant plants have a relatively stable ability to adapt the extreme environment in desert grassland.

关 键 词：放牧 生态化学计量 土壤 荒漠草原 

分 类 号：S812[农业科学—草业科学]