【作者】 赵泽松；

【导师】 龚振平；

【作者基本信息】 东北农业大学 ， 作物栽培学与耕作学， 2010， 硕士

【摘要】 近年来,农田土壤温室气体的排放已经成为众多专家学者研究的一个热点领域。目前,黑龙江省农田温室气体排放研究仍很薄弱,特别是关于农田土壤CO2的排放规律缺少系统研究。本试验以黑龙江省大豆田土壤为研究对象,设置:留茬少耕(MT)、覆盖少耕(MTS)、翻耕(CT)、免耕(NT)、覆盖免耕(NTS)五种耕作方式。通过对大豆田土壤CO2长期连续观测,分析大豆田土壤CO2排放规律;并结合环境参数的分析测试和记录,研究环境影响因子及耕作措施对CO2气体排放的影响;估算CO2排放总量,建立黑龙江省大豆田土壤CO2排放的半经验模型,以便对大豆田土壤CO2排放进行估算;为黑龙江省农田CO2的排放研究提供理论参考与依据。结果表明:大豆生育期间土壤CO2以排放为主。随着大豆生育期的推进,土壤CO2排放呈单峰曲线变化;季节变化差异明显,夏季土壤CO2排放量大,春、秋季节变小;土壤CO2通量日变化峰值出现在12:00~14:00,最小值出现在0:00~4:00,不同时期变化有差异。试验中的5个大豆耕作方式CO2排放通量为:留茬少耕(MT)处理CO2通量84.68 ~354.35mg·m-2·h-1,均值为198.11 mg·m-2·h-1;覆盖少耕(MTS)处理CO2通量55.86~613.51mg·m-2·h-1,均值为321.20 mg·m-2·h-1;翻耕(CT)处理CO2通量71.17~431.98mg·m-2·h-1,均值为198.59 mg·m-2·h-1 ;免耕(NT)处理CO2通量70.27~351.95mg·m-2·h-1,均值为187.19 mg·m-2·h-1;覆盖免耕(NTS)处理CO2通量103.15~590.09mg·m-2·h-1,均值为333.68 mg·m-2·h-1。温度是影响大豆田土壤CO2排放的重要因素。大豆生育期间CO2排放与气温、土壤温度呈y=Aebx相关关系。其中10cm、15cm和20cm土层温度对土壤CO2通量影响较大。留茬少耕(MT)的Q10值的变化范围是2.29~3.58,覆盖少耕(MTS)的Q10值的变化范围是2.28~3.56,翻耕(CT)的Q10值的变化范围是2.11~3.23,免耕(NT)的Q10值的变化范围是2.24~3.49,覆盖免耕(NTS)的Q10值的变化范围是2.03~2.86;从Q10值的变化来看:土壤CO2排放对气温敏感性较弱,对土壤温度敏感性强,而且随着土壤深度的增大,土壤CO2排放对土壤温度的敏感性越强。土壤水分和土壤紧实度影响土壤CO2排放。其中土壤水分受降雨影响较大,降雨后土壤水分增加,CO2排放有增加的趋势;土壤紧实度与土壤CO2排放呈负相关关系。中耕管理措施,可以使CO2通量变大;耕作措施对CO2排放的影响具有显著性差异,特别是有秸秆覆盖的两个处理的CO2通量远大于没有秸秆覆盖的处理;翻耕处理、留茬少耕处理、免耕处理间没有显著性差异,但是免耕处理的CO2通量较低。通过主因素分析,影响土壤CO2排放通量的主因子是土壤温度、取样前十天降水量、大豆生长天数。得出了试验中5种耕作方式条件下的大豆田土壤CO2排放半经验模型,通过土壤温度、取样前十天降水量及大豆生长天数,根据半经验模型就可以估测出大豆田土壤CO2排放量。通过大豆生长期与土壤CO2排放的关系建立起回归方程,对大豆生育期间总的土壤CO2排放量进行估算得出:留茬少耕(MT)处理6.64t·hm-2、覆盖少耕(MTS)处理10.78t·hm-2、翻耕(CT)处理6.46t·hm-2、免耕(NT)处理6.06t·hm-2、覆盖免耕(NTS)处理10.85t·hm-2。更多还原

【Abstract】 Emission fluxes of greenhouse gases from agricultural field soil has became a research focus recently. But there were a few achievements on the emission fluxes of greenhouse gases from agricultural field soil in Heilongjiang province, especially on the law of CO2 emissions. And this study was conducted using the soil from soybean field with five tillage methods including conventional tillage (CT), minimum tillage with stubble (MT), minimum tillage with straw mulch (MTS), no tillage with straw mulch (NTS), no-tillage (NT), to analyze the law of CO2 emissions by long-term continuous observation; to study the effects of various impact factors and tillage methods on the law of CO2 emissions; estimate the total CO2 emissions and establish the semi empirical model, in order to estimate the CO2 emissions from soybean field; to offer theoretical information and basis for the study on he CO2 emissions from farmland in Heilongjiang province. The results showed that:There was a lots of CO2 was exhausted from soybean field during the growth process, CO2 emissions showed a single peak curve with growth process; more in summer than in spring and autumn; CO2 emissions peak and minimum appeared at 12:00~ 14 : 00 and 0:00 ~ 4:00 respectively in a day, and differed with growth stage; CO2 flux was 84.68 ~354.35mg·m-2·h-1 for minimum tillage with stubble (MT), 55.86~613.51mg·m-2·h-1 for minimum tillage with straw mulch (MTS), 71.17~431.98mg·m-2·h-1 for conventional tillage (CT), 70.27 ~ 351.95 mg ? m -2 ? h-1 for no-tillage (NT), 103.15 ~ 590.09mg ? m -2 ? h-1 for no tillage with straw mulch (NTS), their mean value were 198.11 mg·m-2·h-1, 321.20 mg·m-2·h-1, 198.59 mg·m-2·h-1, 187.19 mg·m-2·h-1, and 333.68 mg·m-2·h-1 respectively.Temperature is an important factor which effect CO2 emissions from soybean field. The relationship between CO2 emissions and air temperature and soil temperature can be performed by the formula“y=Aebx”, and the temperature of 10cm, 15 cm and 20 cm soil layer has a great influence on CO2 emissions. The range of Q10 value were 2.29~3.58 for minimum tillage with stubble (MT), 2.28~3.56 for conventional tillage (CT), 2.24~3.49 for no-tillage (NT), and 2.03~2.86 for no tillage with straw mulch (NTS). The sensitivity of CO2 emissions was more strong to temperature of soil layer than to air temperature Judging from Q10 value, and increased with the increment of soil depth.CO2 emissions was effected by soil water content and soil compaction. CO2 emissions increased with the increment of soil water content after raining, and there was a negative correlation between CO2 emissions and soil compaction.CO2 emissions was also increased by inertillage management, and CO2 emissions of minimum tillage with stubble (MT) and minimum tillage with straw mulch (MTS) were more than other treatments without straw covering, which indicated that tillage method has great influence on CO2 emissions; there were no significant difference among conventional tillage (CT)、minimum tillage with stubble (MT) and no-tillage (NT), and CO2 emissions of no-tillage (NT) was minimum.The most important factors effect CO2 emissions was soil temperature, rainfall 10 days before sampling and days after emergence according principal factor analysis. Semi empirical model including the factors above was performed with five different tillage methods treatments.Total CO2 emissions during the soybean growth cycle could be estimated by the regression equation which was established between CO2 emissions and days after emergence were 6.64t·hm-2 for Minimum tillage with stubble (MT), 10.78t·hm-2 for no tillage with straw mulch (NTS), 6.46t·hm-2 for conventional tillage (CT), 6.06t·hm-2 for no-tillage (NT), and 10.85t·hm-2 for no tillage with straw mulch (NTS).更多还原