西北旱区农田土壤N_2O排放空间变化特征及影响因素探讨  

Spatial variation and influence factors of cropland N_2O emission in the Northwest Arid Area

作　　者：张凡[1] 王政[2] 李旭祥[1] 

机构地区：[1]西安交通大学人居环境与建筑工程学院环境科学与技术系,西安710049 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710061

出　　处：《地球环境学报》2016年第3期301-307,共7页Journal of Earth Environment

基　　金：国家自然科学基金项目(41301213);中央高校基本科研业务费;黄土与第四纪地质国家重点实验室开放基金(SKLLQG1522)~~

摘　　要：旱地农田土壤被认为是重要的N_2O排放源,但排放通量及影响因素仍存在不确定性。对西北干旱半干旱地区农田土壤N_2O的排放分析表明,全区N_2O排放通量相对较低,20世纪80—90年代呈波动式增长。N_2O排放的空间格局总体呈现从东南向西南逐渐减少的趋势。陕西地区排放量为75.58 t?a-1,贡献了全区50%的N_2O排放。过量的氮肥施用、较高的降水量以及明显的增温效应是陕西南部N_2O排放增强的主要原因。Background, aim, and scope Upland soil is considered as an important source of N_2O emissions. At present there are many research about the field influence factors on N_2O emissions. However, in traditional rainfed agricultural region of Northwest China, it still lack of in-depth discussion about how these factors affect N_2O emissions synthetically at regional scale. In this study the change trend of N_2O emissions and its influence factors under climate fluctuation and management change were discussed based on regional simulation to support the future prediction of change of cropland N_2O emissions. Materials and methods Daily weather data for simulation were taken from the ModernEra Retrospective Analysis for Research and Application（MERRA）. Soil property data were collected form the national soil survey and the Chinese Soil Atlas. Crop parameters, fertilizer application rates were described in the database using agriclutural census data and other sources. Twenty years simulation about the N_2O emissions of cropland in Northwest China were made based on these database. Results The analysis of the cropland N_2O emission in arid and semi-arid areas of Northwest China show that the regional N_2O flux is relatively low and reduced gradually from southeast to southwest with the decreasing precipitation and temperature overall. The lowest emissions appeared in Ningxia, which account for only 5% of total N_2O emissions. Shaanxi has the highest N_2O emission, accounting for 50% of the total N_2O emissions of the region. There showed significant regional difference and the highest flux appeared in southern Shaanxi. Through the 20 years average N_2O flux was 0.016 kg N？hm^（-2）·a^（-1） and increased fluctuantly in Nothwest China in the 1980 s and 1990 s. Discussion Fertilizer rate has decisive effect to the spatial distribution of N_2O emissions. High N_2O emissions value concentrated in southern Shaanxi and Guanzhong regions mainly due to excessive nitrogen fertilization application in these areas. In addi

关 键 词：农田土壤 N2O 干旱半干旱地区 

分 类 号：S154.1[农业科学—土壤学]