冻融及牲畜排泄物作用下的高寒草地土壤物理特性和氮磷变化  

Effects of Seasonal Freeze-Thaw Cycles and Livestock Excreta Returning on Soil Physical Properties,and Nitrogen and Phosphorus Dynamics in Alpine Grassland

作　　者：杜子银 王小丹[2,3] 洪江涛[2,3] 张青松[1] DU Ziyin;WANG Xiaodan;HONG Jiangtao;ZHANG Qingsong(School of Geographical Sciences, China West Normal University, Nanchong 637009, Sichuan China;Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China;Xainza Alpine Steppe and Wetland Ecosystem Observation Station, Chinese Academy of Sciences, Shenzha 853199, Tibet, China)

机构地区：[1]西华师范大学地理科学学院,四川南充637009 [2]中国科学院、水利部成都山地灾害与环境研究所,成都610041 [3]中国科学院申扎高寒草原与湿地生态系统观测试验站,西藏申扎853199

出　　处：《山地学报》2022年第1期29-42,共14页Mountain Research

基　　金：国家重点研发计划项目(2019YFD1100504);第二次青藏高原综合科学考察研究项目(2019QZKK0404);国家自然科学基金(41807109);西华师范大学博士科研启动项目(17E042)和一般培育项目(18B016)。

摘　　要：在青藏高原高寒草地生态系统中,牲畜排泄物自身冻融及其降解过程调控其养分释放及返还效率,影响草地土壤养分平衡和植被生长的养分供应。当前关于季节性冻融区草地土壤理化特性的研究,多通过定点监测和室内冻融模拟等方式分析冻融循环对土壤物理结构、水热变化及碳氮动态等方面的影响,尚缺乏关于草地土壤季节性冻融与牲畜排泄物耦合效应和作用机制方面的研究报道。本文以藏北高原季节性冻土区为例,通过开展室内冻融模拟试验,探究牲畜排泄物添加与土壤冻融作用下的高寒草地土壤物理特性及氮磷养分变化特征。结果表明:(1)冻融模拟试验30 d后显著降低了5~10 cm和10~15 cm土壤含水量(P<0.05),频繁的冻胀融沉导致土壤团聚体破碎增加了深层土壤粉粒含量。(2)冻融作用增强了土壤氮矿化与硝化作用,牲畜粪尿添加使得表土铵态氮和硝态氮含量最大值分别达到212 mg·kg^(-1)和48.8 mg·kg^(-1)。(3)牲畜排泄物磷的释放和冻融作用下土壤磷的深层渗透是导致不同土层有效磷含量差异的主要因素。本研究有助于认识牲畜排泄物返还与草地土壤季节性冻融的耦合效应和作用机制,并为优化牲畜排泄物管理模式、促进草地生态系统可持续发展提供理论指导。In the alpine grassland ecosystem of the Tibetan Plateau,the degradation process of livestock excreta in freeze-thaw circumstance regulates its nutrient release and return efficiency,which affects the nutrient balance of grassland soil and the nutrient supply of vegetation growth.Research on the physical and chemical properties of grassland soil in seasonal freeze-thaw circumstances mostly analyzed the effects of freeze-thaw cycles on soil physical structure,hydrothermal changes and carbon and nitrogen dynamics through fixed-point monitoring and indoor freeze-thaw simulation.There was still a lack of research reports on the coupling effect and mechanism of seasonal freeze-thaw of grassland soil with livestock excreta.In this paper,taking the seasonal permafrost region of northern Tibet Plateau as an example,the indoor freeze-thaw simulation experiment was carried out to explore the soil physical characteristics and nitrogen and phosphorus nutrient changes of alpine grassland under the action of livestock excreta and soil freezing and thawing.In this study,a seasonal permafrost region on the Northern Tibetan Plateau in China was taken as an example to explore soil physical properties,and nitrogen and phosphorus nutrient dynamics under the coupling effects of livestock excreta returning and soil freeze-thaw cycles by conducting an indoor freeze-thaw simulation experiment.The results showed that:(1)Soil moisture content in 5~10 cm and 10~15 cm depth significantly decreased(P<0.05)after 30 days of experiment,and frequent freeze-thaw settlement resulted in the fragmentation of soil aggregates and increased silt content in deep soil layer.(2)Freeze-thaw cycles enhanced soil nitrogen mineralization and nitrification,and the peaked values of soil ammonium nitrogen and nitrate nitrogen respectively reached 212 and 48.8 mg·kg^(-1) followed by the addition of livestock excreta during the freeze-thaw period.(3)Combined effects of the phosphorus released from livestock excreta and the deep infiltration of soil phosphorus und

关 键 词：冻融 牲畜排泄物 矿化氮 有效磷 高寒草地 青藏高原 

分 类 号：S154.1[农业科学—土壤学]