文献类型：期刊文献

中文题名：氮添加对马尾松人工林土壤团聚体氮矿化及土壤酶活性的影响

英文题名：Effects of nitrogen addition on the mineralization and enzymatic activities within soil aggregates in Pinus massoniana plantation

作者：陈天[1] 程瑞梅[1,2] 王丽君[1] 肖文发[1,2] 沈雅飞[1,2] 孙鹏飞[1] 张萌[1] 曾立雄[1,2]

第一作者：陈天

机构：[1]中国林业科学研究院森林生态环境与自然保护研究所,国家林业和草原局森林生态环境重点实验室,北京100091;[2]南京林业大学南方现代林业协同创新中心,南京210037

年份：2023

卷号：43

期号：16

起止页码：6528-6538

中文期刊名：生态学报

外文期刊名：Acta Ecologica Sinica

收录：CSTPCD;;Scopus;北大核心:【北大核心2020】；CSCD:【CSCD2023_2024】；

基金：中国林业科学院基本科研业务费专项(CAFYBB2021ZE003)。

语种：中文

中文关键词：氮沉降;矿化;生物酶;团聚体;相关性

外文关键词：nitrogen deposition;mineralization;biological enzymes;aggregates;correlation analysis

分类号：S15

摘要：土壤氮库是生态系统氮素重要的源和汇。以三峡库区马尾松(Pinus massoniana)人工林为研究对象,从团聚体视角出发分析土壤养分和酶活性对氮添加的响应规律,以及相应的变化对氮矿化的影响,为预测该地区在大气氮沉降持续增加的背景下土壤氮动态提供参考。设置4种量的氮添加处理(N0:0 kg N hm^(-2)a^(-1);N30:30 kg N hm^(-2)a^(-1);N60:60 kg N hm^(-2)a^(-1);N_(90):_(90) kg N hm^(-2)a^(-1)),将土壤按粒径分为>2000μm(大团聚体)、250—2000μm(小团聚体)和<250μm(微团聚体)3个组分的团聚体,观察团聚体氮矿化特征。结果表明:(1)与对照相比,N30和N60处理提高了有机质(SOM)含量,但土壤SOM和全氮(TN)含量在N_(90)下开始出现下降;氮添加降低了土壤速效磷(aP)含量,在小团聚体中表现最为显著。除微团聚体中的POD和NAG以外,其余3种酶的活性均在N30和N60处理之下被提高。(2)土壤平均净硝化速率整体高于土壤平均净氨化速率;大团聚体和小团聚体中净氨化速率在氮添加处理后显著降低,大团聚体净硝化速率低于其他两个粒径;土壤净氮转化速率在N_(90)处理下最高。(3)土壤养分和无机氮含量与土壤酸性磷酸酶(AP)、N-乙酰-β-D-葡糖苷酶(NAG)、过氧化物酶(POD)、硝酸还原酶(NR)和脲酶(UE)的活性呈显著相关,酶活性变化是多因子综合作用的结果;RDA分析显示,UE与土壤净氨化速率存在显著正相关,NAG和POD是与净氮转化速率分别存在显著正相关和显著负相关的关键土壤酶。综上所述,硝化作用是土壤净氮转化的主要贡献者,微团聚体在土壤氮矿化中发挥主要作用,NAG和POD是改变土壤净氮转化的主要生物酶。此外,氮添加会引起土壤氮素的流失,引起土壤的磷限制,并对土壤养分循环产生显著影响。
Soil nitrogen(N)pools are important sources and sinks of N for ecosystems.A Pinus massoniana plantation in the Three Gorges reservoir area was used as the research object.We analyzed the patterns of responses of soil nutrients and enzyme activities to the addition of N from the perspective of soil aggregates and the corresponding changes in the mineralization of N.These factors were analyzed to provide a reference to predict the dynamics of soil N in the region against the background of a continuous increase in the deposition of atmospheric N.Four levels of the accumulation of N from its addition were established.The amounts added included N0:0 kg N;N30:30 kg N hm^(-2)a^(-1);N60:60 kg N hm^(-2)a^(-1);and N_(90):_(90) kg N hm^(-2)a^(-1).The soil was divided into three component aggregates of>2000μm(large macroaggregates),250-2000μm(small macroaggregates)and<250μm(microaggregates)by particle size to observe the characteristics of nitrogen mineralization by the aggregates.The results showed the following:(1)Compared with the control,the N30 and N60 treatments increased the levels of soil organic matter(SOM),but the soil SOM and levels of total N began to decrease under the addition of N_(90).This addition decreased the levels of available phosphorus(P)in the soil,which was most significant in the small macroaggregates.The activities of all three enzymes were increased under N addition treatment except POD in small macroaggregates as well as AP and NAG in microaggregates.(2)The overall average net nitrification rate in the soil was higher than the average net ammonification rate of the soil.The net ammonification rate in large and small macroaggregates was significantly lower after the addition of N,and the net nitrification rate of the macroaggregates was lower than that of the other two sizes of aggregates.The rate of conversion of net N in the soil was highest under the N_(90) treatment.(3)Soil nutrient and inorganic levels of N significantly correlated with the activities of soil acid phosphatase,N-acetyl-β-D-glucosidase(NAG),peroxidase(POD),nitrate reductase,and urease(UE),and the changes in enzyme activities were the result of a combination of multiple factors.Αredundancy analysis showed that there was a significant positive correlation between UE and net soil ammonification.NAG and POD were the key soil enzymes that significantly positively and negatively correlated with the net conversion of N,respectively.In summary,nitrification is the primary contributor to the net transformation of N in the soil.Microaggregates play a major role in the mineralization of soil N,and NAG and POD are the primary biological enzymes that alter the transformation of net soil N.In addition,the addition of N causes the loss of soil N and limitation of P and significantly affects the cycling of soil nutrients.