【作者】 高秀文；

【导师】 吴文良；

【作者基本信息】 中国农业大学 ， 生态学， 2003， 硕士

【摘要】 受人口、耕地、水资源等条件的限制，粮食的高产仍然非常重要。为我国粮食生产做出重要贡献的高产粮区由于大量氮肥的施用而引发了许多环境问题，如温室气体N₂O浓度增加；同时由于有机碳的大量分解而导致大气中CO₂的浓度也大大增加。本研究以江北第一吨粮县——山东省桓台县为例，采用调查、田间试验与生物地球化学模型模拟相结合的方法对该地区农业生态系统土壤温室气体排放、土壤碳氮平衡进行了初步研究，研究结果表明： 1．华北高产粮区粮田土壤CO₂与N₂O的排放均表现出明显的季节变化规律，夏季排放量最高，冬季排放量最低。其中土壤CO₂于7月下旬达到排放的最大值，最高排放量为33.86g·m^-2·d^-1，土壤CO₂排放与气温及各层地温之间的曲线拟合以指数曲线为最好，但与土壤含水量之间不存在显著的相关关系；土壤N₂O排放于6月底达到最大值，最高排放量为351.31μg·m^-2·h^-1，土壤N₂O的排放主要受土壤水分状况的影响，而与温度的相关性不很明显。由于受复杂的田间管理水平及内部小气候的影响，蔬菜保护地土壤CO₂与N₂O排放的季节变化规律均不如粮田土壤明显。 2．DNDC模型的模拟结果能够表征该地区粮田土壤CO₂与N₂O排放的季节变化特征，对该地区农田土壤中CO₂与N₂O排放的模拟比较准确，模拟结果与田间测定结果较一致。DNDC模型区域模拟研究表明，桓台县2001年农业土壤总有机碳储量为1.4×10⁹kg，单位耕地面积土壤有机碳储量为45115kg·hm^-2。在目前的农田管理措施下土壤碳氮均处于正平衡，但从可持续发展的角度来看，该地区在以后的农业生产中应适当增加有机肥的投入和秸秆还田的比例，减少氮肥的施用量。更多还原

【Abstract】 Because of the population, plow land and water resource etc., the higher grain output is still very important. Many environment problems have appeared because of the excessive application of N fertilizer in the Northern China Plain with high productivity, for example, N2O concentration increase in the atmosphere. Because of the decomposition of soil organic carbon, CO2 concentration in atmosphere has also increased.The experiment site was located in Huantai County of Shandong Province. Soil greenhouse gases emission and carbon-nitrogen budget in the agoecosystem of this region were studied by the method of onsite survey, field experiment and biogeochemistry model simulation. The research results are as follows:1. CO2 and N2O emission from soil in the grain fields of this region changed regularly with the change of the season. The gas fluxes were highest in the summer and lowest in the winter. The peak value of CO2 flux appeared in July 30, and it was 33.86g-m-2-d-1. The CO2 emission was exponentially correlated with air temperature and soil temperature. There was no obvious relation between CO2 emission and soil moisture. The peak value of N2O flux appeared in June 30, and it was 351.31 g-m-2-h-1. The soil moisture was the most important influence factor of N2O. Compared with the grain fields, the seasonal change extents were smaller for CO2 and N2O emission in the protected vegetables fields because of the complicated farmland management and inner microclimate.2. The DNDC model results captured the seasonal change character of two greenhouse gases emission. The simulation results were in agreement with the field data. The carbon-nitrogen budget in the whole region were also simulated by DNDC, and the results showed the total SOC storage in farmland of Huantai County was 1.4 109kg in 2001 and for every hectare, the average SOC storage was 45115.21kg-hm-2. The inputs of carbon and nitrogen were higher than their outputs. From the point of substanable development, this region should increase the manure input and the proportion of crop straw return and decrease the N fertilizer application in the future.更多还原