摘要
免耕技术近年来在南方稻区被广泛推广应用,但该项技术是否有利于减缓稻田综合温室效应目前并不清楚.因此,本文以双季稻-紫云英为研究对象,利用静态箱-气相色谱法分别研究不同耕作方式对稻田CH4和N2O排放、双季稻产量、土壤固碳、稻田净综合增温潜势(GWP)和温室气体强度(GHGI)的影响.试验处理包括常规翻耕(CT)、旋耕(RT)和免耕(NT).结果表明,稻田周年CH4累积排放量为233.5~404.0kg·hm-2·a-1,NT和RT处理分别比CT增加73.1%和35.1%.晚稻生长季CH4排放量占周年CH4排放量的53.7%~66.5%,其中,晚稻移栽至烤田期间CH4累积排放通量占晚稻季排放总量的77.0%~81.3%.稻田N2O累积排放量为4.00~4.82 kg·hm-2·a-1(以N计),但各处理之间没有显著差异.稻田年固碳量为0.36~1.31 t·hm-2·a-1(以C计),其中,NT处理比CT和RT处理分别增加148.4%和261.0%.双季稻周年产量为15.2~17.1 t·hm-2,耕作方式对产量没有显著影响.稻田净GWP为5095.4~7788 kg·hm-2(以CO2当量计),其中,RT和NT处理分别比CT增加52.8%和32.2%.稻田GHGI为0.30~0.46 kg·kg-1(以每kg粮食产量产生的CO2当量计),其中,RT和NT处理分别显著高于CT处理50.1%和45.3%.综上所述,免耕在短期内会增加稻田温室效应,但可以促进土壤固碳量的显著增加,因此,其固碳减排的长期效应还有待观测.
In recent years,no-tillage( NT) technology is widely adopted in the rice-growing area of Southern China. However,it was not clear whether the technology could mitigate the greenhouse effect in rice paddy. The effects of different tillage methods on annual methane( CH4) and nitrous oxide( N2O) emissions,soil carbon sequestration,net global warming potential( GWP) and greenhouse gas intensity( GHGI) were studied by field experiments in double rice-cropping systems in 2013—2014. Methane and N2 O fluxes were measured using static chamber method,and the soil carbon sequestration was estimated by the changes in topsoil( 0 ~ 20 cm) organic carbon( SOC) density. The treatments included NT,rotary tillage( RT) and conventional tillage( CT) in this paper. The results showed that annual CH4 emissions ranged from 233.5 kg·hm-2for the CT plots to 404.4 kg·hm-2forthe NT plots,53.7% ~ 66.5% of which derived from the late-rice season. Annual N2 O emission was 4. 00 ~ 4. 82 kg( N)·hm-2·a-1in the double ricecropping systems. Topsoil SOC sequestration rate was estimated to be 0.36 t( C)·hm-2·a-1for the RT plots and 1. 31 t( C)·hm-2·a-1for the NT plots.Annual grain yield was 15.2 ~ 17.1 t·hm-2for the double cropping rice. Compared with the CT,NT slightly enhanced the net annual GWP,while it was remarkably enhanced by RT. The GHGI significantly increased for the RT and NT plots as compared to the CT plots. The results of this preliminary study suggested that RT and NT could increase comprehensive greenhouse effect under the short-term experiment in Chinese double rice-cropping systems.However,further studies are needed find out the long-term effect of NT on carbon sequestration and mitigation.
出处
《环境科学学报》
CAS
CSCD
北大核心
2015年第6期1887-1895,共9页
Acta Scientiae Circumstantiae
基金
国家科技支撑计划项目(No.2012BAD14B14)
江西省教育厅青年科学基金项目(No.GJJ14306)
江西省高等学校科技落地计划项目(No.12063)~~
