基于BP神经网络模型的全球森林土壤异养硝化过程N_(2)O排放通量估算  

Estimation of N_(2)O emission flux from heterotrophic nitrification process in global forest soils based on BP neural network model

作　　者：刘炳彦 张军辉[1] 耿世聪[1] 陶晶晶 冯月[1] LIU Bing-yan;ZHANG Jun-hui;GENG Shi-cong;TAO Jing-jing;FENG Yue(Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院沈阳应用生态研究所森林生态与管理重点实验室,沈阳110016 [2]中国科学院大学,北京100049

出　　处：《生态学杂志》2022年第2期209-217,共9页Chinese Journal of Ecology

基　　金：国家自然科学基金(41675150,31800413);辽宁省自然科学基金(2019-BS-262)资助。

摘　　要：N_(2)O作为重要的温室气体之一,对地球和人类都有很大的影响。为了深入探究对有机氮异养硝化作用及其产生N_(2)O过程的影响机制,完善全球N_(2)O通量估算模型,本研究采用Pearson相关性分析与广义可加模型(GAM)对全球135个样点有机氮异养硝化速率及其产生N_(2)O速率的影响因子进行分析,然后将主要影响因子作为BP神经网络的输入层来模拟全球森林土壤有机氮异养硝化速率及其产生N_(2)O速率的空间分布。结果显示,土壤pH和土壤C/N是影响有机氮异养硝化速率的主要因素,土壤C/N、土壤孔隙含水量(WFPS)以及土壤温度是影响有机氮异养硝化产生N_(2)O速率的主要因素。全球森林土壤异养硝化速率平均为0.4241(0.0014~0.689)μg N·g^(-1)·d^(-1),异养硝化产生N_(2)O速率平均为0.2936(0.21~1.103)μg N_(2)O·kg^(-1)·d^(-1);北纬50°左右的森林土壤异养硝化速率及其产生的N_(2)O的速率均较高,而在南纬30°至北纬30°的森林土壤异养硝化速率及其N_(2)O的产生速率均较低,尽管在亚洲东北部地区森林土壤异养硝化速率很高,但其产生N_(2)O的速率却很小;全球森林土壤有机氮异养硝化作用下N_(2)O的排放量约为(1.4584±0.3791)Tg N·a^(-1),是天然土壤N_(2)O排放量的26.04%,是全球N_(2)O排放量的8.58%。As one of the main greenhouse gases,N_(2)O has a significant impact on the Earth and human beings.To explore the influence mechanisms of heterotrophic nitrification of organic N and N_(2)O emission process and improve global N_(2)O flux estimation model,Pearson correlation analysis and generalized additive model(GAM)were used to analyze the influencing factors of heterotrophic nitrification rates of organic N and N_(2)O emission rates in 135 sam-pling sites worldwide.The major influencing factors were included into BP neural network model to estimate the spa-tial distribution of heterotrophic nitrification rates of organic N and N_(2)O emission rates in global forest soils.The results showed that soil pH and C/N were the main factors affecting heterotrophic nitrification rate of organic N.Soil C/N,water-filled pore space(WFPS),and temperature are the main factors affecting N_(2)O emission rate during heterotrophic nitrification process.The average heterotrophic nitrification rate was 0.4241(0.0014-0.689)μg N·g^(-1)·d^(-1),and the average N_(2)O emission rate in the heterotrophic nitrification process was 0.2936(0.21-1.103)μg N_(2)O·kg^(-1)·d^(-1) in global forest soils.The heterotrophic nitrification rate and N_(2)O emission rate in the hetero-trophic nitrification process were higher in forest soils around 50°N.In contrast,the two rates were lower in forest soils from 30°S to 30°N.Although heterotrophic nitrification rate was high,N_(2)O emission rate in the heterotrophic nitrification process was low in forest soils in Northeast Asia.N_(2)O emission flux from the heterotrophic nitrification of organic N was(1.4584±0.3791)Tg N·a^(-1)in global forest soils,accounting for 26.04%of N_(2)O emission from natural soils and 8.58%of global N_(2)O emission.

关 键 词：异养硝化速率 异养硝化产生N_(2)O速率 BP神经网络 环境因子 空间分布 

分 类 号：S714[农业科学—林学]