海伦市近30年农田黑土碳储量及其时空变化

发布时间：2018-04-05 23:08

本文选题：黑土　切入点：土壤有机碳　出处：《东北农业大学》2015年硕士论文

【摘要】：中国东北黑土区是世界最为珍贵的黑土区之一,是我国重要的粮食生产基地。有机质含量高,土质肥沃是黑土的主要特征。随着人类活动对土壤的扰动逐年增加,黑土肥力严重退化,同时也造成土壤碳的大量释放,农田土壤碳极易由碳汇向碳源转变。为了明确黑土农田土壤有机碳现状,揭示近30年来土壤碳库变化速率及其关键控制因子以及土壤有机碳变化的驱动机制,本研究以黑龙江省海伦市黑土农田为研究对象,运用地统计学分析方法,结合全国第二次土壤普查资料(1981年)与2011年实地监测数据,对1981年及2011年海伦市农田表层(0~20cm)土壤有机碳储量及其变化速率进行了估算、对土壤有机碳空间分布特征与变化及其影响因素进行了系统研究,同时通过室内培养方法,研究影响土壤有机碳矿化的主要调控因子。结果表明:近30年海伦市农田土壤有机碳含量呈现先降低(1981~2000)后缓慢增加的趋势(2000~2011)。但是在过去30年土壤有机碳储量的总变化依然表现为降低,30年间农田土壤有机碳变化的分布表现出较大的空间变异;1981年、2011年黑龙江省海伦市表层黑土农田土壤有机碳储量分别为22.5×106 Mg和18.2×106 Mg,土壤有机碳密度平均变化速率为-0.49 Mg C/ha/yr。30年内土壤呈现丢碳状态,相对丢碳面积高达约84%,仅有3%表现为固碳,全市农田土壤丢碳量占1981年碳储量的19.1%。不同土壤类型中,初始有机碳密度越高的土壤类型其有机碳降低速率越大,有机碳年变化率与初始有机碳密度呈显著反比关系(P0.001);相比1981年,2011年的土壤碳氮比显著下降(P0.001)。土壤碳氮比的降低可能促进了土壤有机碳的矿化,不利于有机碳的固存;从海伦市东北到西南部,农田土壤平均有机碳呈现从固定到损失的趋势(P0.05)。土壤有机碳的矿化与温度、初始有机碳含量和外源性有机物质的添加密切相关。一般而言,较高温度、初始有机碳含量较高的土壤具有较高的有机碳矿化速率;有效性更高的外源有机物质更有利于土壤有机碳的矿化;但温度和外源碳添加对土壤有机碳矿化的影响受土壤初始有机碳含量的影响。因此,在不同的生产条件下,应根据研究区域因地制宜地,采取适当的固碳措施,实现土壤有机碳的固存。
[Abstract]:Northeast China Black soil region is one of the most precious black soil regions in the world and an important grain production base in China.The organic matter content is high, the soil quality is fertile is the black soil main characteristic.With the increasing disturbance of soil caused by human activities, the fertility of black soil is degraded seriously, which also results in a large amount of soil carbon release, and soil carbon in farmland is easily transformed from carbon sink to carbon source.In order to clarify the present situation of soil organic carbon in black soil farmland, reveal the rate of soil carbon pool change and its key controlling factors and the driving mechanism of soil organic carbon change in recent 30 years, this study took the black soil farmland of Helun City, Heilongjiang Province as the research object.Based on the data of the second national soil census (1981) and the field monitoring data of 2011, the soil organic carbon storage and its change rate were estimated by using geostatistics analysis method.The spatial distribution and variation of soil organic carbon and its influencing factors were systematically studied, and the main regulating factors affecting soil organic carbon mineralization were studied through indoor cultivation.The results showed that the content of soil organic carbon (SOC) decreased first and then increased slowly in recent 30 years.However, the total change of soil organic carbon reserves in the past 30 years still shows that the distribution of soil organic carbon changes in the past 30 years shows a large spatial variation. In 1981, 2011, the surface black soil of Helun City, Heilongjiang Province, showed a large spatial variation.The mechanical carbon storage was 22. 5 脳 10 ~ 6 mg and 18. 2 脳 10 ~ 6 mg, respectively. The average change rate of soil organic carbon density was -0. 49 mg C/ha/yr.30.The area of relative carbon loss is as high as 84%, only 3% is carbon sequestration, the amount of carbon lost from farmland soil in the whole city accounts for 19.1% of the carbon storage in 1981.The decrease of soil carbon / nitrogen ratio may promote the mineralization of soil organic carbon, which is not conducive to the sequestration of organic carbon, and from northeast to southwest of Helen City, the average soil organic carbon in farmland shows the trend from fixation to loss.The mineralization of soil organic carbon is closely related to temperature, initial organic carbon content and the addition of exogenous organic matter.Generally speaking, soil with higher temperature and higher initial organic carbon content has higher organic carbon mineralization rate, higher availability of exogenous organic matter is more favorable to soil organic carbon mineralization.However, the effect of temperature and exogenous carbon addition on soil organic carbon mineralization was affected by soil initial organic carbon content.Therefore, under different production conditions, appropriate carbon sequestration measures should be taken according to local conditions to achieve soil organic carbon sequestration.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S153.6

【参考文献】