秸秆还田对紫色土农田土壤碳排放的影响
文献类型：学位论文
| 作者 | 杜高赞 |
| 学位类别 | 硕士 |
| 答辩日期 | 2011-05-27 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 高美荣 |
| 关键词 | 秸秆还田 紫色土 土壤有机碳 CO2排放 |
| 其他题名 | The Effects of Straw Residue Returned to Emission of Soil Carbon of Purple Soil |
| 学位专业 | 土壤学 |
| 中文摘要 | 全球变暖是当今世界面临的环境问题之一，与该问题密切相关的CO2排放备受关注。土壤碳库是地球五大圈层中最大的碳库，其变化对CO2排放影响巨大。土壤有机碳是土壤碳库的主要赋存形式，可以通过一系列地球物理化学生物过程，以CO2的形式排放的大气中。土壤圈中农田土壤受人类干扰较大，研究表明，通过合理的耕作措施可以提高土壤有机碳含量，但对土壤CO2排放的影响需要进一步研究。 秸秆还田可以改善土壤理化性质，提高土壤有机碳含量。紫色土是一种始成土，土壤有机质含量低，分布范围广，其集中分布地区川中丘陵是我国重要的商品粮生产基地之一，其中旱作农业是该区的主要利用类型之一。因此开展秸秆还田对紫色土农田土壤碳排放影响的研究，对于探明秸秆还田条件下土壤碳动态变化和碳平衡具有重要意义。 本研究依托中国科学院盐亭紫色土农业生态试验站，通过田间控制实验、室内培养实验和理化分析，分析了不同秸秆还田处理条件下紫色土农田土壤有机碳氮含量、土壤微生物生物量碳氮含量、土壤CO2排放速率和累积排放量、土壤有机碳矿化速率和累积矿化量等。主要结论如下：（1） 100%秸秆还田处理显著提高土壤有机碳含量，秸秆还田对土壤有机氮含量影响不显著。土壤微生物生物量碳氮含量受秸秆还田影响显著，秸秆还田量越大，土壤微生物生物量碳氮含量越高，且50%秸秆还田量条件下玉-麦连作处理土壤微生物生物量碳氮含量显著大于休闲处理。对土壤微生物生物量碳与土壤有机碳的比值分析表明，50%秸秆还田玉-麦连作处理具有最大的土壤碳累积趋势。（2） 秸秆还田对土壤CO2排放速率的影响体现在100%秸秆还田处理具有最高的土壤CO2排放速率且与其他三种处理差异显著，对照处理土壤CO2排放速率最低。四种处理土壤CO2累积排放量之间差异显著，秸秆还田量越大，土壤CO2累积排放量越大。秸秆还田在一定程度上提高了土壤水分含量和土壤温度；温度是制约土壤CO2排放的关键因子，秸秆还田可以提高土壤CO2排放的温度敏感性，秸秆还田量越大，提高幅度越高。（3） 100%秸秆还田处理和50%秸秆还田玉-麦连作与休闲处理、对照处理土壤有机矿化速率之间差异显著，秸秆还田可以提高土壤有机碳矿化速率。四种处理土壤有机碳累积矿化量之间差异显著，秸秆还田可以显著提高土壤有机碳累积矿化量，秸秆还田量越大，差异越显著。25 ℃、35 ℃、45 ℃三个温度以及30%WHC、70%WHC、100%WHC三个水分条件下土壤有机碳矿化速率之间差异显著，表明在该温度和水分范围内，温度越高、水分含量越大，土壤有机碳矿化速率越大。 |
| 英文摘要 | Global warming is one of the critical environmental issues of the world today, and CO2 emission which closely related to the issue drawn the most attention. Soil carbon pool is the biggest carbon pool among earth’s spheres, whose change is significance to CO2 emission. Soil organic carbon is the main part of soil carbon, and could translate into CO2 though a series of reactions. Agricultural soil is the most disturbance part of Pedosphere. Studies show that content of soil organic carbon could be increased through reasonable tillage, but further study on soil CO2 emission is needed. Straw returned to the field could improve soil physical and chemical properties and increased content of soil organic carbon. Purple soil is cambisol, content of soil organic carbon was low. Purple soil is wide distribution and it’s mostly distribution area is the hilly area of the central Scichuan Basin where is also a representative traditional agricultural region. And rain-fed agriculture is the main planting in the region. Therefore study the effect of straw returned to field to soil organic carbon emission is critical to analysis soil organic dynamic changes and carbon balance. The study site is located at Yanting Agro-ecological Station of Purple Soil, which of Chinese Academy of Science, situated at 105°27′E, 31°16′N. Through field control experiments, indoor culture experiments, physical and chemical analysis, we study that under the conditions of straw returned to fields, the content of soil organic carbon/ soil organic nitrogen/ soil microbial biomass carbon/ soil microbial biomass nitrogen, fluxes and cumulative emission of soil CO2, fluxes and cumulative emission of soil carbon mineralization. The main conclusions were as follows: (1) 100% straw returned remarkable increased content of soil organic carbon, straw returned to fields on soil organic nitrogen was not significant. Soil microbial biomass carbon and nitrogen content significantly affected by straw returned to fields, and more straw returned, content of soil microbial biomass carbon and nitrogen was higher. Furthermore, under 50% straw returned to field, content of soil microbial biomass carbon and nitrogen of maize-wheat rotation was higher than that of fallow. Study on the rate of soil microbial biomass carbon to soil organic carbon showed that treatments of 50% straw returned maize-wheat rotation had the largest trend in soil carbon accumulation. (2) Straw returned to field on soil CO2 emission rate reflected at that 100% straw returned had the highest soil CO2 fluxes and had significant difference with other treatments. Soil CO2 fluxes of control treatment is lowest. Cumulative emissions among different treatments were significant, more straw returned, more cumulative emission of soil CO2. Straw returned to field could raise soil moisture and soil temperature at some extent, soil temperature is a key constraint factor of soil CO2 emission. Straw returned to fields increased temperature sensitivity of soil CO2 emission, as more straw returned the Q10 higher. (3) Compare with treatments of 50% straw returned fallow and control, mineralization rate of soil organic carbon of treatments of 100% straw returned and 50% straw returned maize-wheat rotation were significantly higher. Straw returned increased mineralization rate of soil organic. Cumulative mineralization of soil organic carbon was significantly different among four treatments. Straw returned increased cumulative mineralization of soil organic carbon, more straw returned, cumulative mineralization of soil organic carbon was higher. Under temperature of 25 ℃、35 ℃、45 ℃ and moisture of 30%WHC、70%WHC、100%WHC, mineralization rate of soil organic at different condition was significant different. That means in the range of temperature and moisture, the higher the temperature, moisture is, the greater the soil organic carbon mineralization rate. |
| 语种 | 中文 |
| 公开日期 | 2013-01-24 |
| 源URL | [http://192.168.143.20:8080/handle/131551/4840]  |
| 专题 | 成都山地灾害与环境研究所_山地表生过程与生态调控重点实验室 |
| 推荐引用方式 GB/T 7714 | 杜高赞. 秸秆还田对紫色土农田土壤碳排放的影响[D]. 北京. 中国科学院研究生院. 2011. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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