华北平原不同管理措施下土壤有机碳动态模拟及时空变化特征

发布时间：2018-06-04 07:57

  本文选题：DNDC模型 + SOC　； 参考：《中国农业大学》2016年博士论文

【摘要】：土壤有机质是土壤肥力的重要指标之一,研究其时空演变规律对于保障粮食产量、提升土壤肥力具有重要的意义。本文基于华北平原衡水、昌平、辛集、郑州、曲周5个长期定位试验点的数据,对DNDC模型在该区域的适用性进行了评价,并分析了不同施肥、耕作和秸秆管理方式对作物产量和土壤有机碳(SOC)含量的影响。针对各试验点化肥配施有机肥(或秸秆)的特点,通过情景分析优化了各个试验点的有机无机配施比例。此外,结合RCP4.5情景下的未来气候数据,应用DNDC模型模拟了各试验点从当前到2099年的作物产量和SOC变化趋势。最后,利用京津冀平原区9个监测点的产量和SOC监测数据进行了区域校验,模拟了该区1980-2014年的作物产量和农田SOC的时空变化特征。全文主要结论如下：DNDC模型对5个长期定位试验点作物产量和SOC含量动态变化的模拟效果总体较好,除了衡水点A1B1处理冬小麦产量的模型效率系数EF值为-0.11,吕平点M处理的夏玉米产量EF值为-0.25以外,5个长期定位试验点冬小麦产量的模型模拟评价指数范围分别为：EF值为0.07-0.94,标准化均方根误差NRMSE值为8.8%-66.4%,一致性指数d值为0.66-0.98；夏玉米产量的模型模拟评价指数分别为：EF值为0.24-0.96,NRMSE值为2.6%-40.1%,d值为0.56-0.99；SOC含量的模型模拟评价指数分别为：EF值为0.09-0.98,NRMSE值为2.9%-24.2%,d值为0.45-0.98。各试验点冬小麦产量、夏玉米产量和表层SOC含量的模拟值与实测值的回归分析的决定系数R2分别为0.741-0.973、0.721-0.933和0.308-0.763,均达到了显著水平,说明该模型可用来模拟华北平原5个长期定位试验点不同耕作、施肥和秸秆还田情况下的作物产量和SOC含量的动态变化过程。总施氮量不变情况下,改变有机肥(或秸秆)替代氮肥比例的优化结果为：在衡水试验点,用玉米秸秆替代氮肥的最佳比例为40%,昌平用鸡粪替代氮肥的最佳比例为30%,辛集用堆肥替代氮肥的最佳比例为40%,郑州用饼肥替代氮肥的最佳比例为10%,曲周翻耕和免耕条件下用麦秸替代氮肥的最佳比例分别为40%和10%。氮肥施用量固定改变有机肥(或秸秆)配施量时,各试验点配比优化结果为：衡水氮肥与玉米秸秆供氮配施比例1：2(氮肥120 kg N hm-2和秸秆23762kg hm-2)为最佳配施比例；昌平化肥与鸡粪配供氮施比例为1：0.33的处理(氮肥150 kg N hm-2和鸡粪4000kg hm-2)为最佳；辛集化肥与堆肥供氮配施比例为1：1.33的处理(氮肥120 kg N hm-2和堆肥32000 kg hm-2)为最佳配施比例；在郑州化肥与饼肥供氮配施比例为1：1.67的处理(氮肥120kg N hm-2和饼肥2857 kg hm-2)为最佳配施比例；在曲周试验点,翻耕和免耕条件下,氮肥与麦秸供氮配施比例均为1：0.4(氮肥120 kg N hm-2和麦秸8727 kg hm-2)为适宜的配施比例。各试验点在RCP4.5和当前气候气候情景下从2000年左右到2099年作物产量的模拟结果表明,在衡水试验点,除不施肥的对照处理(CK)外,RCP4.5情景下各处理作物平均产量比当前气候情景下增加了1.2%-3.3%；昌平试验点RCP4.5情景下各处理作物平均产量比当前气候情景下增加了0.7%-15.6%；辛集试验点RCP4.5情景下各处理作物平均产量比当前气候情景下增加了0.4%-10.5；郑州试验点,除了处理CK,RCP4.5情景下各处理作物平均产量比当前气候情景下增加了4.2%-6.0%；曲周试验点,RCP4.5情景与当前气候情景相比,CK和单施化肥处理(F)平均产量减少了5.9%和5.6%,而单施有机肥处理(M)和化肥配施有机肥处理(FM)平均产量增加了3.7%和3.9%。由各试验点在RCP4.5和当前气候气候情景下到2099年的SOC含量变化模拟结果可知,不施肥(处理CK)条件下,到2099年期间,衡水、昌平的SOC含量在RCP4.5和当前气候情景下均呈现下降趋势；辛集的SOC含量在RCP4.5情景下呈现上升趋势,在Basline情景下呈现下降趋势；郑州、曲周的SOC含量在在RCP4.5和当前气候情景下均呈现上升趋势。在衡水、昌平、辛集和郑州,无论是RCP4.5还是当前气候情景下,化肥配施有机肥(FM处理)条件下SOC含量的年增长速率最高,且RCP4.5情景下的增长速率大于当前气候情景。1980-2014年的35年间,京津冀平原区SOC含量空间分布总体北部较高,南部较低,河北中部霸州地区SOC含量有逐渐降低的趋势,尤其是在2000年之后比较明显,且SOC含量较高的区域面积在逐渐缩减,而天津的武清地区SOC含量在逐渐上升,且SOC含量较高的区域面积在不断扩大。在没有秸秆还田的条件下,有10.7%的区域SOC含量35年来总体呈现下降趋势,位于河北中部地区；SOC增加量为0.4-0.8 gkg-1的区域所占比例最大,为60.3%,包括河北中部、中南部、东部地区以及北京东部和天津；SOC增加量最大(1.5-2 g kg-1)的区域位于河北省南端,仅占总面积的3.5%。而1999年10月开始秸秆还田条件下,35年来SOC含量增加量最大为5-8 gkg-1,最小为1.5-2 g kg-1,且没有SOC含量下降的区域可见秸秆还田对于提升京津冀平原区农田SOC含量效果显著。1980-2014年间,京津冀平原区作物产量总体呈现东北较高,西南较低的趋势,而作物产量较高的区域与SOC含量水平高的区域比较一致。
[Abstract]:Soil organic matter is one of the important indexes of soil fertility. It is of great significance to study the temporal and spatial evolution of the soil to ensure the grain yield and improve the soil fertility. Based on the data of 5 long-term location test points in Hengshui, Changping, Xinji, Zhengzhou and Quzhou, the applicability of the DNDC model in the region is evaluated and analyzed. The effects of different fertilization, tillage and straw management on crop yield and soil organic carbon (SOC) content. In view of the characteristics of the application of organic manure (or straw) in each test point, the organic and inorganic proportions of each test point were optimized through the scenario analysis. In addition, combined with the future climate data under the RCP4.5 scenario, the DNDC model was used to simulate the application. The crop yield and SOC change trend of each test point from current to 2099. Finally, the output of 9 monitoring points in the Beijing Tianjin Hebei plain area and the SOC monitoring data were checked, and the crop yield and the temporal and spatial variation characteristics of the farmland SOC were simulated for 1980-2014 years. The main conclusions are as follows: the DNDC model has 5 long-term positioning tests. The simulation results of the dynamic changes of crop yield and SOC content were better. The EF value of the model efficiency coefficient EF of the winter wheat yield in Hengshui point A1B1 was -0.11, and the summer maize yield EF value of Lv Ping point M was -0.25, and the model evaluation index range of the winter wheat yield of 5 long-term location test points was EF value of 0.07-0.94, The normalized mean square root error NRMSE value is 8.8%-66.4%, the consistency index D value is 0.66-0.98, the model simulation evaluation index of summer maize yield is EF value 0.24-0.96, NRMSE value 2.6%-40.1%, D value is 0.56-0.99, SOC content model simulation evaluation index is respectively. The regression analysis of the simulated and measured values of winter wheat yield, summer maize yield and surface SOC content of each test point were 0.741-0.973,0.721-0.933 and 0.308-0.763, respectively, which reached a significant level, indicating that the model could be used to simulate different tillage, fertilization and straw returning in 5 long-term location test points in North China Plain. The optimal ratio of replacing nitrogen fertilizer with organic manure (or straw) was 40%, the best proportion of replacing nitrogen fertilizer with corn straw was 40% in Hengshui test point, 30% in Changping with chicken manure instead of nitrogen fertilizer, and the best ratio of composting to nitrogen fertilizer in Xinji. For 40%, the optimum proportion of cake fertilizer to replace nitrogen fertilizer in Zhengzhou was 10%. The optimum proportion of wheat straw replacing nitrogen fertilizer under the condition of Quzhou and no tillage was 40% and 10%., respectively, when the amount of nitrogen fertilizer was fixed to change organic manure (or straw), the optimum results were as follows: the ratio of nitrogen fertilizer to nitrogen fertilizer in Hengshui and corn straw was 1:2 (nitrogen fertilizer 12). 0 kg N hm-2 and straw 23762kg hm-2) were the best proportions; the optimum proportion of nitrogen fertilizer in Changping and chicken manure was 1:0.33 (nitrogen fertilizer 150 kg N hm-2 and chicken manure 4000kg hm-2), and the ratio of nitrogen fertilizer to composting was the best proportion of 1:1.33. The optimum proportion of fertilizer and cake fertilizer in Zhengzhou (nitrogen fertilizer 120kg N hm-2 and cake fertilizer 2857 kg hm-2) was the best proportion. Under the quad test point, the ratio of nitrogen fertilizer to wheat straw was 1:0.4 (nitrogen fertilizer 120 kg N hm-2 and wheat straw 8727 kg hm-2). 4.5 and the current climate and climate scenarios from around 2000 to 2099 crop yield simulation results show that in Hengshui test point, in addition to no fertilizer control treatment (CK), under the RCP4.5 scenario, the average yield of each crop increased by 1.2%-3.3% under the current climate scenario, and the average yield of each crop under the Changping test point RCP4.5 scenario was compared to the average yield. 0.7%-15.6% was added under the pre climate scenario; the average yield of each crop under the scenario of Xinji test point RCP4.5 increased by 0.4%-10.5 under the current climate scenario; in Zhengzhou test point, the average yield of each crop was 4.2%-6.0% below the current climate scenario in addition to the treatment of CK and RCP4.5; the Quzhou test point, the RCP4.5 scene and the current situation Compared with the climate scenarios, the average yield of CK and single fertilizer treatment (F) decreased by 5.9% and 5.6%, while the average yield of single application organic fertilizer treatment (M) and chemical fertilizer treatment (FM) increased by 3.7% and 3.9%. by the simulation results of SOC content changes from each test point in RCP4.5 and the current climate climate scenario to 2099, and no fertilizer (CK) conditions were not used. In the period of 2099, the content of SOC in Hengshui and Changping decreased in both RCP4.5 and current climate scenarios; the SOC content in Xinji showed an upward trend under the RCP4.5 scenario, and in the Basline scenario, the content of SOC in the Quzhou period showed an upward trend under the RCP4.5 and the current climate scenarios. In Hengshui, Changping, In Xinji and Zhengzhou, under the condition of RCP4.5 or current climate, the annual growth rate of SOC content is the highest under the condition of chemical fertilizer combined with organic fertilizer (FM treatment), and the growth rate under the RCP4.5 scenario is greater than the 35 years of the current climate scenario.1980-2014 years. The spatial distribution of SOC content in the Beijing Tianjin Hebei plain area is higher in the north, lower in the south, in the middle of Hebei. The content of SOC in Bazhou area has been gradually decreasing, especially after 2000, and the area of high SOC content is decreasing gradually, while the SOC content of Wuqing area in Tianjin is increasing gradually, and the area of higher SOC content is expanding. In the condition of no straw returning, there are 10.7% region SOC content for 35 years. The overall decline was in the central region of Hebei; the largest proportion of SOC increased to 0.4-0.8 gkg-1, which was 60.3%, including central Hebei, South Central, Eastern and Eastern Beijing and Tianjin; the region of the largest SOC increment (1.5-2 g kg-1) was located at the southern end of Hebei Province, only the total area 3.5%. and October 1999 straw began. Under the condition of straw returning, the maximum increase of SOC content in 35 years was 5-8 gkg-1, and the minimum was 1.5-2 g kg-1, and there was no decrease in SOC content in the region that the effect of straw returning to the farmland SOC content in the plain area of Beijing, Tianjin and Hebei was significant.1980-2014, and the crop yield in Beijing, Tianjin and Hebei plain was higher in the northeast and lower in the southwest. The areas with higher yield were more consistent with those with higher SOC content.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S153.6
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本文编号：1976608