种植模式协同秸秆管理对稻田温室气体排放的影响

Effects of crop patterns and straw management on greenhouse gas emissions in paddy fields

  • 摘要: 在浙江省嘉善县选取1.3 hm2稻田,设置节水旱管+秸秆还田/不还田与普通淹灌+秸秆还田/不还田2种种植模式4个处理组(以下简称节水还田、节水不还田、普通还田、普通不还田),采用静态箱-气相色谱法获取28批次336个稻田甲烷(CH4)和氧化亚氮(N2O)排放数据,同时结合土壤颗粒有机碳(POC)等6个环境因子12个样品分析结果,探究种植模式协同秸秆管理对稻田温室气体排放特征的影响。结果显示:1)CH4累计排放量依次为普通还田>普通不还田>节水还田>节水不还田,N2O累计排放量为普通还田>节水不还田>节水还田>普通不还田。全球增温潜势(GWP)与温室气体排放强度(GHGI),普通还田最高,分别为7 696.03 kg/hm2(以CO2计,全文同)、0.97 kg/kg;节水不还田最低,分别为2 110.12 kg/hm2、0.21 kg/kg。2)最小显著差异法分析结果表明,各处理组之间CH4累计排放量存在显著差异。据Pearson相关性分析结果,CH4累计排放量与POC含量呈极显著正相关(P<0.01),与微生物碳含量呈显著正相关(P<0.05);N2O累计排放量则与硝态氮(\mathrmNO_3^- -N)含量呈显著正相关(P<0.05),GWP、GHGI与POC含量呈极显著正相关(P<0.01)。3)种植模式与秸秆管理均对CH4累计排放量有极显著影响(P<0.01),二者交互作用对CH4累计排放量、N2O累计排放量有显著影响(P<0.05)。研究表明,水稻节水旱管种植协同秸秆还田措施是一种气候友好型的高产经济种植模式,既可保证粮食安全,降低秸秆离田成本,对于减缓全球温室效应也具有积极作用。

     

    Abstract: A 1.3 hm2 paddy field was selected in Jiashan County, Zhejiang Province, and four treatment groups, briefly referred to as water-saving irrigation, water-saving non-returning, ordinary returning, and ordinary non-returning, were set up with two planting modes, namely water-saving drought pipe + straw returning/non-returning and ordinary inundation irrigation + straw returning/non-returning. The methane (CH4) and nitrous oxide (N2O) emission data from 336 rice fields in 28 batches obtained by static box gas chromatography, in combination with the analysis results of 12 samples of 6 environmental factors, including soil particulate organic carbon (POC), were used to explore the influence of planting mode and straw management on greenhouse gas emission characteristics of rice fields. The results showed as follows: (1) The cumulative CH4 emissions were in the order of ordinary returning > ordinary non-returning > water-saving returning > water-saving non-returning, and the cumulative N2O emissions were in the order of ordinary returning > water-saving non-returning > water-saving returning > ordinary non-returning. The global warming potential (GWP) and greenhouse gas emission intensity (GHGI) of ordinary returning group were the highest, being 7 696.03 kg/hm2 (calculated as CO2) and 0.97 kg/kg, and those of water-saving non-returning group were the lowest, being 2 110.12 kg/hm2 and 0.21 kg/kg, respectively. (2) The analysis results of the least significant difference method showed significant differences in cumulative CH4 emissions among the treatment groups. According to Pearson correlation analysis, the cumulative CH4 emission was extremely significantly positively correlated with POC content (P <0.01) and significantly positively correlated with microbial carbon content (P <0.05). The cumulative emission of N2O was significantly positively correlated with \mathrmNO_3^- -N content (P <0.05), and GWP and GHGI were extremely significantly positively correlated with POC content (P <0.01). (3) Both planting mode and straw management had extremely significant effects on CH4 cumulative emissions (P <0.01), and their interaction had significant effects on CH4 cumulative emissions and N2O cumulative emissions (P <0.05). The research shows that rice water-saving and drought-tube planting combined with straw returning is a climate-friendly high-yield and economic planting model, which can ensure food security, reduce the cost of straw leaving the field, and play a positive role in slowing down the global greenhouse effect.

     

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