降水季节性分配对亚热带森林土壤氮矿化的影响  

Effect of seasonal distribution in precipitation on soil nitrogen mineralization in a subtropical forest

作　　者：纪永康 马楠[1] 张慧[1] 李翠环 马元丹[1] 武启骞 李彦 JI Yongkang;MA Nan;ZHANG Hui;LI Cuihuan;MA Yuandan;WU Qiqian;LI Yan(State Key Laboratory of Subtropical Silviculture,Zhejiang A&F University,Hangzhou 311300,China)

机构地区：[1]浙江农林大学省部共建亚热带森林培育国家重点实验室,杭州311300

出　　处：《应用生态学报》2024年第1期186-194,共9页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(41730638,31901294);中国博士后科学基金项目(2020M671795,2020T130600);浙江农林大学科研发展基金项目(2021LFR010);浙江省“尖兵”、“领雁”研发攻关计划项目(2022C02019);高等学校学科创新引智计划项目(D18008)资助。

摘　　要：土壤氮矿化是生态系统养分循环的关键过程,但降水季节性分配对土壤氮矿化的作用机制尚不明确。本研究于2020—2022年在我国长江中下游亚热带森林进行降水控制试验,采用野外树脂芯原位培养法,分别设置对照(CK)、干季更干、湿季极端降水增加(T_(1))和干季更干、湿季降水等比例增加(T_(2))3种处理,探究降水季节性分配对土壤氮矿化的影响。结果表明:T_(1)和T_(2)分别使干季土壤净硝化速率显著降低57.9%和72.5%,净氮矿化速率显著降低82.5%和89.6%,而使湿季土壤净硝化速率显著提高64.3%和79.5%,净氮矿化速率显著提高64.2%和81.1%,且湿季降水等比例增加比湿季极端降水增加更有利于土壤氮矿化进程。此外,结构方程模型表明,降水季节性分配的变化能够通过改变土壤含水量、铵态氮和微生物生物量氮以及土壤C∶N对亚热带森林土壤氮矿化进程产生显著影响。以上结果对研究土壤氮循环等生态过程具有重要的参考意义,有利于更准确地评估未来降水格局变化对亚热带森林生态系统的影响。Soil N mineralization is a key process of nutrient cycling in ecosystems.The mechanism of the seasonal distribution of precipitation on soil N mineralization remains unclear.We conducted a precipitation manipulation experiment in a subtropical forest in the middle and lower reaches of the Yangtze River in China from 2020 to 2022,with three treatments,including control(CK),decreased precipitation in the dry season with extremely increased precipitation in the wet season(T_(1)),and decreased precipitation in the dry season with proportionally increased precipitation in the wet season(T_(2)).With in situ resin core method,we explored the effect of seasonal distribution of precipitation on soil N mineralization.The results showed that T_(1) and T_(2) significantly decreased dry season net nitrification rate by 57.9%and 72.5%and the net N mineralization rate by 82.5%and 89.6%,respectively,and significantly increased wet season net nitrification rate by 64.3%and 79.5%and net N mineralization rate by 64.2%and 81.1%,respectively.Proportionally increased precipitation in the wet season was more conducive to soil N mineralization process than extremely increased precipitation in the wet season.Results of the structural equation model showed that change in seasonal distribution of precipitation could significantly affect soil N mineralization processes in the subtropical forest by changing soil water content,ammonium nitrogen,microbial biomass nitrogen,and soil C:N.Our results had important reference for understanding soil nitrogen cycling and other ecological processes,and were conducive to more accurate assessment on the impacts of future changes in seasonal precipitation pattern on subtropical forest ecosystems.

关 键 词：土壤氮转化 亚热带森林 降水格局 生物地球化学循环 干湿季 

分 类 号：S714[农业科学—林学]