摘要
绿洲灰漠土冻融交替明显,但缺乏该时期气体通量及动态变化方面的研究。选取NPK(氮磷钾肥)、NPKS(0.9NPK+0.1秸秆氮)、NPKM(1/3NPK+2/3羊粪氮)和NPKM+(1.5倍NPKM)处理作为研究对象,利用静态箱气相色谱法开展2013—2014年春季冻融期温室气体排放观测试验。结果显示,春季冻融期间,有机肥添加处理CO_2排放量较高,其中NPKM+和NPKM处理CO_2平均排放量分别为C 113 mg m^(-2) h^(-1)和85 mg m^(-2) h^(-1),其次为NPKS(72 mg m^(-2) h^(-1))、NPK(75 mg m^(-2) h^(-1))和CK(35 mg m^(-2) h^(-1))。同样,NPKM+和NPKM处理有相对更高的N_2O排放,春冻平均排放通量分别为N 73μg m^(-2) h^(-1)和42μg m^(-2) h^(-1),显著高于NPKS(22μg m^(-2) h^(-1))和NPK(17μg m^(-2) h^(-1))处理(p<0.05)。CH_4排放量相对较低,各处理无明显差异(p>0.05)。分析发现,N_2O在冻融期呈现先增加后急剧减少的趋势,CO_2变幅不明显。与全年总排放量相比,冻融期(27 d)N_2O的排放量占全年的9%~18%,CH_4冻融期间排放比重占全年排放量的6%~14%。所以,冻融交替期是灰漠土农田温室气体排放的相对高发时期,估算温室气体排放时应充分考虑。
【Objective】Freezing and thawing alternation is a natural phenomenon,especially in high latitude areas,like the northeast and northwest parts of China,The oasis in the arid regions where the winter is long with plenty of snowfall are naturally subjected to frequent freeze-thaw alternations in spring.A large number of researches have demonstrated that freeze-thaw alternation could lead to emission of high volumes of greenhouse gas.So,it is supposed that the croplands in the area studied may emit high volumes of greenhouse gases in winter and spring,but dynamics of the emission and fluxes of greenhouse gases emitted during this period are not well documented.【Method】Along-term field experiment was initiated in April1990 at the National Grey Desert Soil Station of Xinjiang Academy of Agricultural Sciences,and designed to have a total of 12 treatments,among which 5 fertilization treatments,i.e.CK（No fertilization）,NPK（nitrogen,phosphorus and potassium）,NPKS（0.9NPK＋0.1 Straw nitrogen）,NPKM（1/3NPK＋2/3sheep manure-nitrogen）and NPKM＋（1.5NPKM）,were laid out for this study in a cropland of grey desert soil,and emissions of greenhouse gases during the freezing and thawing alternation periods of 2013 and2014 monitored with the static box method and gas chromatography.【Result】Results show that Treatments NPKM and NPKM＋reached C 113 and 85 mg m^-2 h^-1 on average in CO2 emission,respectively,relatively higher than the other three Treatments NPKS,NPK and CK,being 72 mg m^-2 h^-1,75 mg m^-2 h^-1 and35 mg m^-2 h^-1,respectively.Similarly,Treatments NPKM＋and NPKM was relatively higher in N2O flux,too,reaching N 73 and 42μg m^-2 h^-1 on average,respectively,which were obviously much higher than22μg m^-2 h^-1 in Treatment NPKS and 17μg m^-2 h^-1 in Treatment NPK（p0.05）.However,the treatments were all relatively low and did not differ much in CH4 emission from each other.N2O emission displayed a significant rising trend in flux during the early freeze-thaw period,but a declining one in the late period.CO2 emission exhibited a similarly trend,too,but not so strong.The N2O emission during the freezing and thawing alternation period（27 days）reached N 0.1~0.5 kg hm^-2 a^-1,accounting for 9%~18%of the total of a year,while the CH（4 ）emission during the period accounted for 6%~14%of the total and did not vary much with the treatment.【Conclusion】The freezing and thawing period in spring is a time period of high frequency in greenhouse gas emission in the oasis of gray desert soil.Especially during the early and mid phases of the alternation period,both CO2 and N2O emissions were apparently on a rising trend,but during the late phase they dropped significantly along with the decline of soil moisture content.Among all the treatments,Treatments NPKM and NPKM＋had significantly longer emission periods and higher emission fluxes,while Treatments NPK and NPKS had higher peak values,but short emission periods.In addition,snowfall in winter was found to be a key factor affecting emissions of greenhouse gases.High snowfall could increase the soil water content and sustain the content for a longer period of time,which could in turn prolong the greenhouse gas emission period,while low snowfall could hardly sustain high soil water content for long,thus shortening the emission period.To sum up,all the findings in this experiment demonstrate that the emission of greenhouse gases from farmland of gray desert soil in the oases is high during the freezing and thawing alternation period.So it is necessary to take into account the greenhouse gas emission during this time period,when estimating volume of greenhouse gas emission and its warming potential in this area.
出处
《土壤学报》
CAS
CSCD
北大核心
2018年第1期159-173,共15页
Acta Pedologica Sinica
基金
国家自然科学基金项目(41461066)
国家公益性行业专项资助(201103003)
国家重点基础研究发展计划项目(973)(2014CB954202)资助~~
关键词
灰漠土
绿洲农田
施肥
N2O、CO2和CH4
冻融交替
Grey desert soil
Oasis cropland, Fertilization
N2O, CO2 and CH4
Freezing andthawing alternation
