摘要本实验用静态箱对桑园气体样品进行了采集，气体样品的N2O浓度用气相色谱仪进行检测，并计算出N2O气体排放通量。同时用PVC对桑园土壤样品进行采集，再分析0~30cm深度土样的基本理化性质及其酶活性特征。结果表明，桑园近地面大气N2O平均浓度为345。53ppb，高于全球大气N2O背景值320ppb。计算得到桑园土壤N2O平均排放通量为33。87µg∙m-2∙h-1，表明桑园土壤是N2O的排放源。温度与土壤含水量是影响桑园土壤N2O排放通量的重要因素。桑园土壤pH值在7。3到7。6之间，呈碱性；含水量在18%~20%之间；有机质含量在0。86%左右。不同深度的土壤脲酶活性相差不大，表明土壤中氮肥含量分布较为均匀，但是磷酸酶和蔗糖酶的活性随着土壤深度的增加而减小，过氧化氢酶活性呈现出表层和深层土壤活性高、中间层土壤活性低的特点。86262

毕业论文关键词：桑园土壤；N2O；排放通量；酶活性

Abstract The acquisition of mulberry gas samples were used in this experiment of static box ,gas chromatograph was used to detect the N2O concentration in the gas sample, and calculate the N2O gas emission flux。 At the same time in the mulberry field soil samples were collected using PVC, the basic physical and chemical properties and enzyme activities of 0~30cm deep soil samples were analyzed。 Results show that, Mulberry near surface atmospheric average N2O concentration of 345。53ppb, higher than the global atmospheric 320ppb background value N2O。 The calculated mulberry soil N2O fluxes was 33。87µg∙m-2∙h-1, it showed that is the source of N2O emissions of mulberry soil。 Temperature and soil moisture is an important factor affecting the mulberry soil N2O emission flux。 Mulberry soil pH value between 7。3 and 7。6, alkaline; Water content in 18%~20%; The content of organic matter is about 0。86%。 The soil urease activity in different depth had little difference, it showed that the distribution of nitrogen fertilizer in soil was more uniform, catalase activity showed a high activity in the surface and deep soil, and the activity of the middle layer was low。

Keywords: Mulberry soil; N2O; Emission flux; Enzymatic activity

目  录

第一章 绪论 1

1。1 研究背景 1

1。2 土壤N2O产生机理 1

1。2。1 硝化作用 2

1。2。2 反硝化作用 3

1。3 国内外研究进展 3

1。3。1农业生态系统土壤N2O排放研究进展 4

1。3。2自然生态系统土壤N2O排放研究进展 6

1。4 土壤酶活性特征 7

1。5 本课题研究意义 8

第二章 采样区域和实验方法 9

2。1 研究区域概况 9

2。2 样品的采集 9

2。2。1 气体样品的采集 9

2。2。1 土壤样品的采集及预处理 9

2。3 实验试剂与仪器 10

2。3。1 实验试剂 10

2。3。2 实验设备 11

2。4 测定指标及其分析方法 11

2。4。1 气体样品N2O浓度的测定及排放通量的计算 11

2。4。2 土壤主要理化性质的测定