青藏高原高寒草地土壤速效氮矿化能力对温度和有机肥添加的响应  

Responses of soil available nitrogen mineralization ability to temperature and organic fertilizer addition in alpine grasslands of the Qinghai-Tibet Plateau

作　　者：郭雅婧 李辉鹏 张其斌 白璐 张伟 陈宝林 桑建辉 李渊[3] 沈禹颖[3] GUO Yajing;LI Huipeng;ZHANG Qibin;BAI Lu;ZHANG Wei;CHEN Baolin;SANG Jianhui;LI Yuan;SHEN Yuying(Gansu High-tech Innovation Service Center,Lanzhou 7303013,Gansu,China;Gansu Ziwuling Forestry Management Bureau Heshui Branch,Qingyang 745400,Gansu,China;State Key Laboratory of Grassland Agro-ecosystems,College of Pastoral Agriculture Science and Technology/State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems/Gansu Qingyang Grassland Agricultural Ecosystem National Field Science Observation and Research Station,Lanzhou 730020,Gansu,China)

机构地区：[1]甘肃省高新技术创业服务中心,甘肃兰州7303013 [2]甘肃省子午岭林业管理局合水分局,甘肃庆阳745400 [3]兰州大学草地农业科技学院/草种创新与草地农业生态系统全国重点实验室/甘肃庆阳草地农业生态系统国家野外科学观测研究站,甘肃兰州730020

出　　处：《草业科学》2024年第5期1048-1056,共9页Pratacultural Science

基　　金：甘肃省自然科学基金项目“豆科牧草促进粮−草轮作系统碳平衡的途径与机制(22JR5RA455)”。

摘　　要：青藏高原高寒草地土壤氮素矿化是影响全球碳氮循环和草地生态系统演替的关键过程。本研究通过不同温度(5、15和25℃)和有机氮添加梯度(0、15、45和75 kg·hm^(−2))的室内培养试验,测定土壤氮矿化速率、矿化势以及矿化反应速率常数对处理的响应,旨在探究温度和有机肥添加对青藏高原高寒草地土壤速效氮供应能力的影响。结果表明:土壤氮素矿化量随温度的升高而增加,25℃下明显高于15和5℃;有机氮添加(15~45 kg·hm^(−2))显著提高了土壤铵态氮的矿化量,继续增加至75 kg·hm^(−2)时,氮素矿化能力降低;土壤氮矿化速率随培养时间的增加先增加后降低,添加有机氮可以增加高寒草地土壤氮素矿化速率,在氮素添加量为45 kg·hm^(−2)时达到峰值;温度决定了高寒草地土壤氮素矿化势,对矿化速率常数k没有明显影响。综上所述,添加15~45 kg·hm^(−2)有机氮及较高的温度条件有利于提高青藏高原高寒草地土壤速效氮的矿化能力,这为高寒草原地区的草地管理和有机肥施用提供了理论依据。Nitrogen mineralization in the soil of alpine grasslands on the Tibetan Plateau is a key process affecting the global carbon and nitrogen cycle,as well as the succession of grassland ecosystems.The aim of this study was to explore the effects of temperature and organic fertilizer additions on the nitrogen availability in the soil of these alpine grasslands.Through incubation experiments involving different temperatures(5,15,and 25℃)and gradients of organic nitrogen addition(0,15,45,and 75 kg·ha^(−1)),we analyzed changes in soil nitrogen mineralization rates,mineralization potential,and mineralization reaction rate.The results showed that soil nitrogen mineralization increased with rising temperature,with values significantly higher at 25℃than at 15℃and 5℃.Organic nitrogen addition(15~45 kg·ha^(−1))significantly increased the mineralization of ammoniacal nitrogen in the soil.However,further increasing the fertilization gradient to 75 kg·ha^(−1)reduced the nitrogen mineralization capacity.The soil nitrogen mineralization rate exhibited a single peak trend with increasing incubation time,and the addition of organic nitrogen could increase the nitrogen mineralization rate in alpine grassland soil,reaching its maximum under N 45 treatment.Temperature determined the mineralization potential of nitrogen in alpine grassland soil,but did not significantly affect the mineralization rate,k.In summary,the addition of 15~45 kg·ha^(−1)of organic nitrogen and higher temperature conditions are beneficial for enhancing the mineralization capacity of rapidly available nitrogen in the soil of alpine grasslands on the Tibetan Plateau,providing a theoretical basis for grassland management and organic fertilizer application in alpine grassland regions.

关 键 词：高寒草甸 氮素添加 有机氮 氮素矿化速率 氮素矿化潜力 室内培养 温度 

分 类 号：S15[农业科学—土壤学]