旱地小麦产量形成对气候变化的响应及其耕作措施调控

It will provide some theoretical basis for the sustainable development of regional grain production that the response and adaptation mechanism of regional crop production to climate changes were Objectively understand and then farming measures adapted to climate changes were put forward. Researches on tillage practices that can adjust farmland environment thereby regulate the formation of crop yields are more, However, researches on regulation of tillage measures to climate changes are relatively less.　For this reason, based on the APSIM model, this project will simulate spring wheat yield formation to climate changes under different tillage measures with systems engineering measures to discuss the response and regulation mechanism by long-term field experiment of different tillage measures and additional tests. The main purpose is to analyze and explore the following question: The suitability of the model which simulates spring wheat yield formation under coupling conditions of tillage measures and climate changes; Characteristics and trends of climate change, and the responding mechanism of wheat yield formation to climate change under different tillage measures; To determine the threshold value of climatic factors and tillage measures on wheat yield formation, and to evaluate the effect of tillage measures dealing with climate change, finally to provide theoretical and technical basis for high yield and efficient tillage measures on semiarid region under the changing climate background in the future.

客观理解区域作物生产对气候变化的响应和适应机理，提出适应气候变化的农作措施，可为区域粮食生产的可持续发展提供一定的理论依据。而耕作措施可以调节农田环境，进而调节作物产量形成的研究较多，但耕作措施对气候变化的调控研究相对较少。为此，本项目基于APSIM模型，通过长期不同耕作措施的大田定位试验和补充试验，运用系统工程的方法模拟研究不同耕作措施春小麦产量形成对气候变化的响应及其调控机制。旨在揭示和探索：在耕作措施和气候变化耦合条件下模型模拟旱地小麦产量形成过程的适宜性；气候变化特征和趋势，以及不同耕作措施小麦产量形成对气候变化的响应机制；确定气候因子和耕作措施对小麦产量形成的影响阈值，评估耕作措施应对气候变化的调控效应，为未来气候变化背景下半干旱地区春小麦高产高效栽培的耕作措施提供理论依据。

为客观理解区域作物生产对气候变化的响应和适应机理，提出适应气候变化的农作措施，本项目基于APSIM模型，通过长期积累的大田试验资料和补充试验数据，模拟研究不同耕作措施旱地春小麦产量形成对气候变化的响应及其调控机制。研究结果如下：.1.采用智能算法优化APSIM模型中与小麦产量形成过程相关的机理参数，参数优化后，APSIM模型针对黄土丘陵区不同耕作措施小麦产量形成对气候变化的适宜性较好。.2.研究区气候变化趋于暖干化，温度上升是重要的气候变化特征，全年和春小麦全生育期平均温度距平上升幅度最大值分别为2.05℃和1.77℃；降水呈下降趋势；太阳辐射微弱上升。研究区降水对产量呈极显著正相关，充足的光照已经使小麦生产对太阳辐射的需求饱和，太阳辐射微弱上升对产量的影响相对于降水与温度变化对产量的影响较小，因此通过耕作措施的调控抑止土壤蒸发耗水及水土流失，保持小麦可利用的水分供应，提高水分利用效率，这将是研究区小麦生产应对气候变化行之有效的方法。.3. 研究区旱地小麦产量应对气候变化的影响主要是应对降水变化的影响；研究区域内降水对产量一直是正效应，温度对产量负效应，且降水与温度的交互作用十分明显。降水、温度变化与秸秆覆盖量耦合条件下，降水对产量正效应；温度对产量负效应，研究区温度升高幅度达到2.8℃时，产量出现极小值；覆盖量对产量正效应，考虑到投入产出效益，研究区惯用的收获后秸秆全部还田的做法是适宜的。秸秆覆盖可进一步促进降水的增产作用，相较于只增加降水的情形，降水每增加5%，同时覆盖量每增加1000kg/hm2，产量平均增幅由21.57%提高到22.25%，提高了0.68%；秸秆覆盖可补偿温度的减产作用，相较于只升高温度的情形，温度每升高0.5℃，同时覆盖量每增加1000kg/hm2，产量平均减幅下降由6.44%下降到5.93%，下降了0.51%。适合研究区气候变化下小麦产量形成的最优耕作措施调控方案为正常播期、免耕＋秸秆覆盖，收获后秸秆全部还田。.项目针对旱地小麦提出的应对气候变化的最优耕作方案可广泛的适用于中国的干旱地区。