单 位：
西北农林科技大学旱区农业水土工程教育部重点实验室;河海大学水文水资源与水利工程科学国家重点实验室;西北农林科技大学水利与建筑工程学院陕西杨凌
关键词：
土壤;温室气体;排放控制;N2O;加气灌溉;番茄
摘 要：
加气灌溉引起的土壤中氧气含量改变势必会影响N_2O的产生和排放。为了揭示加气灌溉对秋冬茬温室番茄地土壤N_2O排放的影响,2014年采用静态箱-气相色谱法对加气灌溉土壤N_2O排放进行原位观测,研究秋冬茬温室番茄地土壤N_2O排放对加气灌溉的动态响应。试验采用灌水量(充分灌溉、亏缺灌溉)和加气(加气、不加气)的双因素设计,设置4个处理,分别为加气亏缺灌溉(A1)、不加气亏缺灌溉(CK1)、加气充分灌溉(A2)和不加气充分灌溉(CK2)。结果表明:不同加气灌溉模式下土壤N_2O排放均主要集中在番茄果实膨大期,其他时期排放水平较低。加气和充分供水处理均增加了番茄整个生育期的土壤N_2O排放量,以A2处理最大(120.34 mg/m2),分别是A1和CK1处理的1.89和4.21倍(P<0.01),而与CK2处理差异性不显著(P=0.078)。此外,不同灌水水平不加气处理,除N_2O排放主峰值点外,N_2O排放通量与土壤充水孔隙率(water-filled pore space,WFPS)存在指数正相关关系(P<0.05),WFPS在46.0%~52.1%时观测到N_2O剧烈释放。可见,加气灌溉增加了温室番茄地土壤N_2O排放,且在亏缺灌溉条件下,加气灌溉对温室番茄地土壤N_2O排放的影响显著。研究结果为评估加气灌溉技术的农田生态效应及设施菜地温室气体减排提供参考。
译 名：
Soil N_2O emission characteristics of greenhouse tomato fields under aerated irrigation
作 者：
Chen Hui;Hou Huijing;Cai Huanjie;Zhu Yan;College of Water Resources and Architectural Engineering, Northwest A&F University;Key Laboratory for Agriculture Soil and Water Engineering in Arid Area Ministry of Education, Northwest A&F University;
关键词：
soils;;greenhouse gas;;emission control;;N2O;;aerated irrigation;;tomato
摘 要：
Global warming and ozone depletion caused by greenhouse gas emissions are two major global environmental issues. The contribution of facility vegetable fields abundant with high N input to soil nitrous oxide emissions cannot be negligible. Crop growth, yield and water use efficiency under aerated irrigation have been done much work, while the effects of aerated irrigation on greenhouse gas emissions have never been reported. Changes of oxygen content in the soil caused by the aerated irrigation are bound to affect the production and emissions of nitrous oxide. Field experiments by using the method of static chamber/gas chromatography were conducted to determine the effects of aerated irrigation on seasonal N_2O fluxes, and cumulative emissions of N_2O from soils in greenhouse tomato fields in autumn-winter season and soil water-filled pore space(WFPS) at 20 cm depth in the solar greenhouse of the Key Laboratory of Agricultural Soil and Water Engineering in Arid Area sponsored by Ministry of Education(34°20′N, 108°04′E), at Northwest A&F University, in Yangling, Shaanxi Province of China, from August 13, 2014 to December 28, 2014. Two factors(irrigation and aeration) were designed in the experiment to reveal the effects of aerated irrigation on soil N_2O emissions. Four treatments with three replications(each plot size 4.0 m × 0.8 m) were contained in the experiment: aerated deficit irrigation(A1), unaerated deficit irrigation(CK1), aerated full irrigation(A2) and unaerated full irrigation(CK2). The results showed that N_2O fluxes under different irrigation methods roughly showed a trend of decrease after the first increase. The first and secondary peaks of N_2O fluxes were observed at fruit expanding stage and maturing stage of tomato, respectively, while kept at a low level in other periods. Both seasonal N_2O fluxes and cumulative emissions of N_2O at different growth stage of tomato followed the same pattern: A2>CK2>A1>CK1. And both N_2O fluxes and cumulative emissions of N_2O from soils in tomato fields at different growth stages for each treatment mainly concentrated at fruit expanding stage. In addition, aeration and full water supply treatments increased the soil N_2O emissions during the whole tomato growth period compared to unaeration and deficit water supply treatments. The average value of N22 O fluxes(38.00 μg/(m·h)) for A2 treatment increased by 85.9% and 264.7% compared with that for A1 and CK1 treatment(P<0.05), respectively, while the difference was not significant when compared to CK2 treatment(P>0.05). The maximum value about cumulative emission of N_2O(120.34 mg/m2) for A2 treatment was 1.89 and 4.21 times as much as A1 and CK1(P<0.01), respectively, while the difference was not significant when compared to CK2 treatment(P=0.078). Compared with unaerated irrigation, aerated irrigation did not increase N_2O emissions from soils in greenhouse tomato fields significantly under full water supply condition(P=0.078), while increased N_2O emissions significantly under deficit water supply condition(P<0.01). In addition, WFPS kept at a relatively high level for each treatment during the whole tomato growth stage. Except the main peaks, N_2O fluxes increased with WFPS increasing. Exponential positive correlations between N_2O fluxes and soil water-filled pore space(WFPS) were observed under unaerated irrigation methods of different irrigation level(P<0.05), while the relationships under aerated irrigation methods were not significant(P>0.05). Furthermore, peaks of N_2O emissions were negative with WFPS, and N_2O intense release was observed when WFPS was between 46.0%-52.1%. The results suggested that aerated irrigation increased soil N_2O emissions in tomato fields, and the difference was significant under deficit water supply condition. This study provides valuble information for assessing farmland ecological effects of aerated irrigation and mitigating greenhouse gas emissions to greenhouse soils.
