生物炭添加对黄河三角洲盐渍土有机质矿化及改良研究

	生物炭添加对黄河三角洲盐渍土有机质矿化及改良研究
	孙军娜
学位类型	博士
导师	邵宏波
	2014-05-13
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位专业	环境科学
关键词	生物炭盐渍土有机质矿化土壤改良作物生长
摘要	黄河三角洲的盐渍化环境造成土壤有机质含量低、土壤保水保肥能力弱，微生物多样性和活性低，极大地限制了作物的生长。生物炭作为一种新型环境功能材料，在温室气体减排和土壤改良方面的应用引起了广泛的关注。研究表明生物炭可以提高土壤有机质含量，增强土壤肥力并提高作物产量。生物炭对盐渍土有机质矿化作用和改良效果尚缺乏系统的报道。为此，本研究首先选取八种原材料，研究了炭化温度和炭化时间对制得生物炭产率、固定碳/挥发分/灰分、pH值、酸性/碱性官能团、电导率及碘吸附值的影响。其次，重点研究了不同环境因子（温度和水分）对土壤有机质矿化的影响，并深入探讨了干湿交替现象对盐渍土有机质矿化的影响。最后，为了有效指导生物炭在农业生产的应用，论文通过野外大田试验和室内盆栽试验，研究了生物炭添加对作物产量及土壤pH值、有机质、营养元素等理化性质的影响。主要结论如下：（1）在300-600℃的炭化温度内，随着炭化温度的升高，生物炭中的固定碳含量、pH值和碱性官能团增大，而产率、吸附性能、酸性官能团减少。杏树绿叶、地瓜藤生物炭的pH值较高，添加后会增加盐渍土的pH值，不利于盐渍土的改良。梧桐树干、芦苇、杨树枯叶不如小麦秸秆、花生壳、玉米秸秆三种农业废弃物来源广。因此，本研究主要以小麦秸秆、花生壳、玉米秸秆为原料，在炭化温度较低时制得的生物炭来进行改良盐渍土的研究。（2）土壤-生物炭混合后的累积矿化量随着温度升高而增大。加入300℃生物炭处理，15℃时的累积矿化量为367µgCO₂/gsoil，温度增加到25℃、35℃时，累积矿化量分别增加了77.9%、201%。各处理累积矿化量的大小为：土+秸秆+生物炭（S+W+C1）>土+秸秆（S+W）>土+4%（W/W）300℃生物炭（S+2C1）>土+2%300℃生物炭（S+C1）>土+2%600℃生物炭（S+C2），纯土（S）。培养温度为25℃时，S+W处理的平均矿化速率为48.53µgCO₂/gsoil/d，S+C1处理的平均矿化速率为2.97µgCO₂/gsoil/d。因此，有机物料炭化能大幅减少有机质的矿化速率，这对减少温室气体排放，增加土壤碳库储量有重要意义。S+W+C1处理的平均矿化速率为79.6µgCO₂/gsoil/d，低于S+W处理的平均矿化速率（114.5µgCO₂/gsoil/d）。秸秆与生物炭混施的方式，能降低秸秆在土壤中的分解速率，延长秸秆还田的增碳作用。除S、S+C2处理，Two-pool模型很好地拟合了其他处理有机质的矿化过程（R²>0.9）。由拟合参数可知，分解初期主要消耗活性碳库中的有机碳，后期主要消耗惰性碳库中的有机碳。各处理温度敏感系数Q₁₀的变化范围分别为1.28-1.34(S)、1.36-2.18(S+W)、1.7-1.78(S+C1)、1.21-2.28(S+C2)、1.57-1.59(S+2C1)、1.6-2.04(S+W+C1)。随着培养温度的升高，Q₁₀降低。在15℃-25℃时，S+C1处理的Q₁₀值为1.78，在25℃-35℃时，Q₁₀值为1.7。（3）水分对土壤-生物炭有机质矿化速率的影响较为复杂。对纯土处理，有机碳矿化速率在淹水条件下最高。加入生物炭处理，在15℃、25℃时，70%FC条件下累积矿化量最高。35℃时，一定量的生物炭加入量在淹水条件下有机质的累积矿化量最高，如果加入量过多，也会抑制有机质的矿化。各处理干湿交替的累积矿化量均比恒湿条件的累积矿化量低。与恒湿条件相比，在第一、第三周期末，S+W处理干湿交替的降幅分别为13.8%、26.3%。而对S+2C1处理干湿交替的降幅为14.2%、3.6%。这说明低温生物炭的添加能减少干旱对盐渍土的影响。（4）野外大田试验结果表明，与对照226kg/hm²的棉花产量相比，生物炭加入量为15t/hm²-35t/hm²时，棉花的产量增加了141%-224%。生物炭的加入增加了盐渍土的孔隙度，使土壤容重降低。当生物炭加入量为15t/hm²-25t/hm²时，土壤容重达到适宜作物生长的容重范围（1.2-1.3g/cm³）。与对照相比，生物炭添加增加了土壤总有机碳和有效磷含量，且随着生物炭加入量增多而增大。但实验末期，生物炭添加对盐渍土含水量和电导率的影响不大。（5）室内盆栽试验为野外大田试验提供了有效的补充。结果表明，生物炭对盐地碱蓬的促进作用在施用量上存在一个限值。当小麦生物炭施用量为5g/kg-10g/kg时，随着生物炭加入量的增加，盐地碱蓬干重逐渐增大，增幅为11.7%-115%。当生物炭施用量增加为20g/kg时，盐地碱蓬干重反而有所下降。盐地碱蓬的地下生物量只有在加入量达到20g/kg时，才明显增大，比对照增加了26.4%。等量不同原料生物炭的添加中，花生生物炭对盐地碱蓬干重及地下生物量的促进作用比小麦生物炭大。不同原料添加中，小麦生物炭对盐渍土pH值的改善作用最大，盐渍土pH值降低了约0.2个单位。在小麦生物炭加入量为10g/kg、20g/kg时，土壤总有机碳含量显著增加，小麦/玉米/花生生物炭添加对土壤总有机碳的增幅效果相差不大。仅在小麦加入量为20mg/g时，土壤有效磷的含量显著增加，碱化度显著降低。不同原料添加中，玉米生物炭对土壤有效磷含量的增幅最大，为34.1%。花生生物炭对土壤碱化度的改善作用最明显，降幅为32.7%。各处理生物炭添加对土壤微生物碳含量及阳离子交换量的改善作用并未达到显著水平。需建立长期的监测实验，以研究生物炭施用的作物学效应及对盐渍土理化性质的改良效果。
其他摘要	In Yellow River Delta, the growth of plant and agricultural production have been limited in some extent by the lower organic carbon content, poor water and fertility preservation capacity and lower microbial activity and diversity. Biochar, as a new-type environment functional material, has caused the extensive concern on greenhouse gas emission reduction and soil amelioration. It is found that the biochar application can increase the organic matter content and fertility, especially improve the plant yield. There has not been a systematical and profound study on the effects of biochar application on saline soil organic carbon mineralization and amelioration. First, different charred temperature and pyrolysis time were conducted on the preparation of biochar to find out the tendency of biochar yield, fixed carbon content/ ash/ volatile components, pH, functional groups, iodine value. Then, the effects of biochar on soil organic matter mineralization were discussed on different temperature and water content condition, especially the drying-rewetting condition. Finally, in order to address the reasonable application of biochar in agriculture after the growth of plant, pot experiment and field experiment were conducted to explore the potential function of biochar on the growth of plant and yield. In application, after the growth of plant, the change of soil pH, organic carbon content, nutrients contents and so on were characterized to examine the effect of biochar application on the amendment of saline soil. The main research findings were shown as follows: (1) The content of fixed carbon, pH value and basic functional groups increased with the pyrolysis temperature in the studied range of 300-600℃. However, the yield, acidic functional groups and iodine value of biochar followed the opposite trend, decreasing considerably with pyrolysis temperature. The application of apricot leaves and sweet potato vine was unfavorable for the improvement of saline soil due to the higher pH value. The source of wood, reed and dead leaves was deficiency. Thus, wheat straw, corn stalk and peanut hull which prepared at lower pyrolysis temperature were chosen to get suitable properties of biochar to ameliorate the saline soil. (2) Increased temperature had a significant positive effect on soil respiration rate。The accumulated mineralization of 300℃ biochar application was 367µgCO₂/gsoil at 15℃ and increased by 77.9% and 201% at 25℃ and 35℃, respectively. The order of different treatments was soil application with biochar and wheat straw(S+W+C1)>soil application with wheat straw(S+W)>soil application with 300℃ biochar in the percentage of 4%(S+2C1)>soil application with 300℃ biochar in the percentage of 2%(S+C1)>soil application with 600℃ biochar in the percentage of 2%(S+C2) and control(S). At 25℃, the mineralized rate of S+W was 48.53µgCO₂/gsoil/d while S+C1 was 2.97µgCO₂/gsoil/d. Thus, adding the charred biomass was favorable to the reduction of greenhouse gas emissions and the increase of soil carbon storage. The mineralized rate of S+W+C1 which was 35.34µgCO₂/gsoil/d was lower than the treatment of S+W. So the way added with both wheat straw and biochar can reduce the mineralized rate of wheat straw and increase the carbon content in a long period. The mineralization of soil organic matter was successfully estimated by Two-pool model except for the treatment of S and S+C2 and R²>0.9. At early stages of soil organic carbon decomposition process, the mineralization of active pool took up the dominate position while lately, the mineralization of slow pool was dominative. The range of temperature sensibility coefficient (Q₁₀) of different treatment was 1.28-1.34(S), 1.36-2.18(S+W), 1.7-1.78(S+C1), 1.21-2.28(S+C2), 1.57-1.59(S+2C1) and 1.6-2.04(S+W+C1). Q₁₀ value of soil respiration was correlated negatively with temperature. The Q₁₀ of S+C1 was 1.78 and 1.7 at 15℃-25℃ and 25℃-35℃, respectively. (3) The effect of soil water content on soil respiration rate was complex. The accumulated mineralization of control was highest under submergence. In the treatment of biochar application, the accumulated mineralization was highest under 70%FC in 15℃ and 25℃. However, in 35℃, the highest accumulated mineralization of biochar application was under submergence. But if biochar application was excessive, the mineralization of organic matter under submergence was also inhibited. In application, compared with constant moisture (CM), cumulative C mineralization of dry-rewetting (DW) was lower during the experimental period in all treatments. Compared with CM, the cumulative C mineralization of DW in S+W was 13.8% and 26.3% reduction at the end of cycle 1 and 3, while in S+2C₁, the extent of reduction was 14.2% and 3.6%, respectively. Thus, biochar application can effectively decrease the effect of DW cycles on soil C mineralization. (4) On the field experiment, compared with controls, the cotton yield increased by 141%-224% under the application of wheat straw biochar at 10t/hm²-35t/hm². Bulk density of saline soil arrived at the ideal standard of 1.2-1.3g/cm³ at the rate of 10t/hm²-25t/hm². The soil porosity, available phosphorus and organic matter content increased as the amount of biochar application. In the earlier incubation, biochar application had no effect on soil water content. While later in the experiment, the soil water content increased by 2.8% and 3.8% at the rate of 25t/hm² and 35t/hm², respectively. (5) On the pot experiment, both wheat straw biochar and peanut shell biochar increased the Suaeda salsa yield and root biomass. The S.salsa yield increased by 11.7%-115% under wheat straw biochar application at a range of 5g/kg to 10g/kg. When biochar application was 20g/kg, the S.salsa yield decrease instead. The underground biomass of S.salsa increase by 26.4% only at 20g/kg biochar application. Added with equal different raw material biochar, the effect of peanut hull biochar on the growth of S.salsa was higher than that of wheat straw biochar. The improvement of wheat straw biochar on saline soil pH was the highest among the equal different raw material biochar application and the reduction was 0.2 units. The content of total organic matter increased only at 10g/kg and 20g/kg biochar application. The effect of wheat straw biochar, corn stalk biochar and peanut hull biochar application on soil organic matter was similar. The increment of available phosphorus content and reduction of saline soil exchange sodium percentage in a large scale was only at 20g/kg wheat straw biochar application. The effect of corn stalk biochar on available phosphorus content was highest and the increment was 34.1%. The effect of peanut hull biochar on reduction of exchange sodium percentage was highest and the reduction was 32.7%. However, it played no significant role in the improvement of soil microbial biomass carbon and cation exchange capacity. Long period monitoring system need be set up to assess the amendment of biochar on saline soil properties.
语种	中文
文献类型	学位论文
条目标识符	http://ir.yic.ac.cn/handle/133337/6813
专题	中国科学院烟台海岸带研究所知识产出_学位论文
推荐引用方式 GB/T 7714	孙军娜. 生物炭添加对黄河三角洲盐渍土有机质矿化及改良研究[D]. 北京. 中国科学院研究生院,2014.

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