农牧交错带多时间尺度气候变化与气候智慧型农牧业应对机制

Agro-pastoral ecotone is quite sensitive to climate change, and also is one of the most fragile ecosystems. In this research, multiple time scales analysis on climate change and the corresponding response of ecosystems would be addressed, which is crucial important to adopt policies and strategies to adapt the climate change effectively. Effective time series analysis, e.g. wavelet analysis, cyclic analysis and spectral analysis etc. would be introduced to exploit the multivariate time series data of climate and ecological areas, and consequently work out the characteristic of climate change on the large scale and moderate scale, respectively, and the response of cropland and grassland ecosystem to the climate change. Additionally, the data derived from field surveys, sample investigations and field experiments analysis would be used to analyze the characteristic of climate change and the effect on the ecosystems on the small scale. The Agricultural Production System Simulation Model (APSIM) and CENTURY ecosystem model are two effective tools to conduct the response of crops and pasture to climate change on multiple time scale, respectively, and could be used to simulate the effects of different crop types, varieties, sowing date, intercropping, crop rotation, rainwater harvesting, and fertilization on crop yields and cropland ecosystem factors, and the compensatory effects of grazing intensity on grassland ecosystem. Based on the analysis of the response of cropland and grassland ecosystems to climate change on multiple time scales, and the effects of a series of management strategies on the crop yields and cropland ecosystem factors, the well-organized sustainable adaptation strategies, including carbon sequestration, carbon emission reduction, yields increment, efficient and sustainability, would be proposed to cropland and grassland ecosystems. And subsequently, we would make the ecological and economic benefits of agro-pasture production systems tend to be Pareto Optimum.

农牧交错带是气候变化敏感地带，也是生态系统脆弱带，研究该区域的多时间尺度气候变化及相应的生态系统响应，对采取政策和技术措施有效地应对气候变化有重要意义。该项目拟将小波分析、周期分析等时间序列谱分析方法，用于气候和生态领域的多维时间序列数据挖掘，给出北方农牧交错带大时间尺度和中时间尺度气候变化特征及相应的农田和草地生态系统结构的响应；通过野外考察与样方调查、田间试验和野外试验分析小时间尺度气候变化特征对生态系统功能的影响。引入APSIM作物模型和CENTURY草地模型分析多时间尺度气候变化下作物和牧草的长时间序列响应，以及模拟改变作物种类、品种、播种期、间套作、轮作、集雨、施肥对作物产量和农田生态系统要素的影响，模拟放牧强度对草地生态系统的补偿效应，探索气候智慧型农牧业的应对机制，提出农田和草地系统固碳、减排、增产、高效、可持续的有序适应策略，使农牧业生产系统的生态经济效益趋向于帕累托最优。

北方农牧交错带生态系统受到来自自然和人为的两重驱动，系统脆弱，受到外来压力胁迫超过其缓冲能力，就有可能导致不可恢复的退化。本研究通过对北方农牧交错带的气候数据和遥感数据的不同时间尺度分析，结合野外考察与样方调查，得到了北方农牧交错带多时间尺度气候变化特征及相应的农田和草地生态系统结构的响应；基于田间试验和野外试验，探索气候智慧型农牧业的应对机制，提出农田和草地系统固碳、减排、增产、高效、可持续的有序适应策略。主要结果如下：.1、北方农牧交错带多时间尺度气候变化特征。年尺度上，内蒙古地区呈显著增温趋势，增温速率超过全球平均增温速度的两倍。风速和日照时数均呈现显著下降的趋势，年降水量有轻微下降的趋势，湿润指数减少的趋势明显，在不断的变暖变干。月尺度上，2月份研究区的平均温度、最高和最低温度增幅最大。温度和风速是影响研究区参考作物蒸散量变化的重要的因素。.2、气候变化对农牧生态系统的影响。气候增暖对草地物候期产生了一定的影响，整体的生育期均有前移的趋势。草地叶面积指数与温度、降水量、日照时数之间具有极显著的线性关系，当月的降水量对草地生长有较大的影响。气候变化使得农作物潜在产量呈波动下降的趋势，适宜播种期发生了变化。 .3、通过田间试验，提出了基于调整播种期、间套作、轮作、微地形集雨、优化施肥等技术的气候智慧型农牧系统增产高效可持续的有序适应策略。确定了向日葵最优播期、最优灌溉、最优施肥的“三优化”生产模式，同时发现不同密度单盘粒重的影响比较显著，不同的宽窄行设置对向日葵产量以及籽粒品质均无显著性影响；间套作产量高于单作产量，且东西行向利于作物获得水分、辐射和养分，产量最优；调整播期能够提高作物产量，定量化了北方农牧交错带马铃薯、小麦、莜麦、油菜、向日葵等五大作物的弹性播期；优化了施肥方式，有效减少了温室气体排放量；提出了田间微集雨技术，提高了北方农牧交错带雨养农业的产量和水分利用效率。