丰雨年旱作农业区不同耕作措施麦豆地 N2O、CH4的排放

摘要

采用静态箱－气相色谱法采集丰雨年旱作农业区不同耕作措施春小麦－豌豆地排放气体并计算通量，研究耕作措施、土壤温度和土壤含水量对春小麦－豌豆地N2 O和CH4排放的影响，其中，耕作措施包括免耕秸秆覆盖（NTS）、免耕不覆盖（NT）和传统耕作＋秸秆还田（TS）以及传统耕作不覆盖（T）四种。研究结果表明：不同措施麦豆地均为N2O的排放源，春小麦地通量波动范围0．018～0．146 mg·m-2·h－1，豌豆地通量波动范围0．024～0．210 mg·m-2·h－1，全生育期春小麦地N2O平均排放通量大小顺序：T＞TS＞NT＞NTS ，而豌豆地大小顺序：T＞NTS＞NT＞TS；不同耕作措施麦豆地均表现为CH4的吸收汇，春小麦地吸收通量的波动范围0．051～0．212 mg·m-2·h－1，豌豆地的波动范围0．057～0．193 mg·m-2·h－1，全生育期春小麦地CH4平均吸收通量大小顺序：NTS＞NT＞TS＞T ，豌豆地大小顺序：NTS＞TS＞NT＞T；不同耕作措施对N2 O和CH4全生育期通量有明显的影响，TS、NT和NTS三种耕作措施较T措施而言，有效地减少了N2 O的排放且增加CH4的吸收；丰雨年，土壤温度和土壤含水量对旱作农业区N2 O和CH4排放综合影响权重有所降低。%This study aims to illustrate the effect of tillage patters ,soil temperature and soil moisture content on N2O and CH4 emissions of spring wheat-pea rotation fields in a wet year .Gases (N2O and CH4 ) emission were deter-mined under four tillage patterns including no-tillage with straw mulching (NTS ) , no-tillage without straw mulching (NT ) ,conventional tillage with straw mulching (TS ) and conventional tillage without straw mulching (T ) by static cham-ber-gas chromatographic techniques .The results showed that both wheat and pea fields were emission sources of N 2 O re-gardless of the patters .Emission flux of spring wheat field ranged from 0 .018 mg·m-2·h-1 to 0 .146 mg·m-2·h-1 , while that from pea field was from 0 .024 mg·m-2·h-1 to 0 .210 mg·m-2·h-1 .N2O average emission flux of spring wheat field was in the order of T>NT>NTS>TS ,while that from pea field T>NTS>NT>TS .Both wheat and pea fields were sinks of CH4 irrespective of tillage patters .The absorbed flux of spring wheat and pea field were from 0 .051 mg·m-2·h-1 to 0 .212 mg·m-2·h-1 and 0 .057 mg·m-2·h-1 to 0 .193 mg·m-2·h-1 ,respectively .Average CH4 ab-sorption fluxes of spring wheat and pea field was in the order of NTS >NT>TS>T and NTS>TS>NT>T ,respective-ly .Significant effects on fluxes of N2O and CH4 existed across the tillage patterns .Compared with T ,TS ,NT and NTS reduced emissions of N2 O effectively and increased the absorption of CH4 .The comprehensive influence of soil tempera-ture and soil moisture content on N2O and CH4 emission in dryland farming in a wet year was lower than that in a normal year .