【作者】 聂志刚；

【导师】 李广；

【作者基本信息】 甘肃农业大学 ， 生态学（农业生态学）， 2022， 博士

【摘要】 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。本研究选择黄土丘陵典型雨养农业区——定西市,以旱地春小麦(Triticum aestivum L.)为研究对象,立足2002—2005年长期积累与2015—2017年补充的大田试验数据,结合1971—2017年研究区历年统计年鉴数据,运用本土化APSIM模型(Agricultural Production System Simulator)对气候变化下不同耕作措施春小麦产量形成的响应进行分析,评估气候变化与耕作措施耦合互作效应对春小麦产量形成的影响,旨在为合理调整耕作制度,实现耕作措施对旱地春小麦生产的调控以更好应对未来气候变化这一科学问题提供基础理论依据。结果表明:(1)采用混合蛙跳算法优化APSIM中与春小麦产量形成过程相关的产量、干物质积累与分配、叶片生长等子模型机理参数。参数优化后,传统耕作(T)、免耕(NT)、传统耕作+秸秆覆盖(TS)和免耕+秸秆覆盖(NTS)4种耕作措施,早播(ESW)、正常播期(NSW)和晚播(LSW)3个播期处理下,春小麦全生育期及各生育阶段持续天数、籽粒干物质、产量和籽粒蛋白质含量的模拟值与实测值均控制在-15%～+15%误差线内;均方根误差(RMSE)分别为0.7～3.0 d、15.4～143.1 kg/hm~2、66.4～121.9 kg/hm~2和0.2%～1.1%,归一化均方根误差(NRMSE)分别为2.34%～6.93%、1.38%～9.89%、1.23%～9.66%和1.31%～9.94%,模型模拟精度较高。APSIM对气候变化下不同耕作措施旱地春小麦产量形成的适宜性较好。(2)研究区多年气候变化特征分析可知,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,年际波动大,波动范围平均值正距平55.11 mm,负距平-52.82 mm;太阳辐射微弱上升。相关性分析可知,降水对产量呈极显著正相关,充足的光照已经使春小麦生产对太阳辐射的需求饱和,其微弱上升对产量的影响相对于降水与温度变化对产量影响较小。基于APSIM的旱地春小麦生长气候适宜性诊断分析评价也反映,春小麦全生育期内,光照和温度基本处于较适宜水平以上,降水是主要限制因素。气候变化趋于暖干化下,通过耕作措施的调控抑止土壤蒸发耗水及水土流失,保持春小麦可利用的水分供应,提高水分利用效率,这将是旱地春小麦生产应对气候变化行之有效的方法。(3)气候变化下不同耕作措施春小麦产量形成动态变化模拟分析可知,不同耕作措施下,随着播期的推迟,春小麦从种子萌发阶段到器官建成阶段(播种—开花)生育持续天数明显减少,籽粒形成阶段(开花—成熟)播期对生育持续天数影响不大;籽粒干物质早播略好于正常播;正常播期(NSW)产量比早播(ESW)产量和晚播产量都要高,差距范围在70.59～114.61 kg/hm~2和209.49～313.98 kg/hm~2;且籽粒蛋白质含量正常播期也最高。不同播期下,耕作措施对生长发育持续天数影响均不显著;籽粒干物质和产量的有益程度排序均表现为免耕+秸秆覆盖(NTS)>传统耕作+秸秆覆盖(TS)>免耕(NT)>传统耕作(T);4种耕作措施均表现出籽粒蛋白质含量与产量呈先增加后减少的关系,免耕+覆盖(NTS)保证产量的同时籽粒蛋白质含量减少的态势最缓。气候变化下正常播期、免耕+秸秆覆盖(NTS)最利于旱地春小麦的高效、优质生产。(4)不同秸秆覆盖量梯度分组模拟试验表明,研究区春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;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。设置研究区未来气候变化试验场景,降水、温度与秸秆覆盖量耦合模拟试验进一步表明,降水对产量正效应;温度对产量负效应,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。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1000 kg/hm~2,产量平均增幅由21.57%提高到22.25%,提高了0.68%,秸秆覆盖可促进降水的增产作用;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1000 kg/hm~2,产量平均减幅由6.44%下降到5.93%,下降了0.51%,秸秆覆盖可补偿温度的减产作用。耕作中注重结合秸秆覆盖量的调控,产量有一定提高;考虑到投入产出效益,适合研究区气候变化下旱地春小麦生产的最优耕作措施调控方案为正常播期、免耕+秸秆覆盖(NTS),收获后秸秆全部还田。本文的研究将混合蛙跳算法应用于APSIM模型参数的优化,模型本土化适应能力进一步提升,突破了旱地春小麦智能化生产管理中知识决策的关键技术瓶颈。将APSIM模型运用于耕作制度的调整,证实研究区气候变化趋于暖干化下,正常播期、免耕+秸秆覆盖(NTS)对旱地春小麦生产是合理的耕作制度,同时注重结合秸秆覆盖量的调控可适当增产,并考虑到投入产出效益,最适宜的覆盖做法是收获后秸秆全部还田。更多还原

【Abstract】 An objective understanding of the response and adaptation mechanism of regional crop production to climate change and the proposed farming measures to adapt to climate change can provide a certain theoretical basis for the sustainable development of regional food production.In this study,we selected Dingxi City,a typical rain-fed agricultural area in the Loess Hills,and used dryland spring wheat(Triticum aestivum L.)as the study object,based on the long-term accumulation of field trial data from 2002 to 2005 and the supplemented field trial data from 2015 to 2017,combined with the statistical yearbook data of the study area from 1971 to 2017.We used the localized APSIM model(Agricultural Production System Simulator)to analyze the response of spring wheat yield formation under climate change with different tillage measures,and to assess the impact of coupled interaction effects between climate change and tillage measures on spring wheat yield formation,with the aim of providing a basic theoretical basis for rational adjustment of tillage measures and regulation of tillage measures on dryland spring wheat production to better respond to the scientific problem of future climate change.The results showed that:1.The shuffled frog leaping algorithm was used to optimize the mechanism parameters,which related to the yield formation of spring wheat in the APSIM model,and included sub-model parameters such as yield,dry matter accumulation and distribution,leaf growth,etc.After parameter optimization,under four kinds of tillage measures:conventional tillage(T),no tillage(NT),conventional tillage with straw cover(TS)and no tillage with straw cover(NTS),and three kinds of sowing dates:early sowing(ESW),normal sowing(NSW)and late sowing(LSW),the error between simulated and observed value of whole growth period with continuous days at each growth stage,grain dry matter,yield and grain protein content of spring wheat was controlled within the range from-15%to+15%;the root mean square error(RMSE)ranged from 0.7 d to 3.0 d,15.4 kg/ha~2 to 143.1 kg/ha~2,66.4 kg/ha~2 to121.9 kg/ha~2,and 0.2%to 1.1%,respectively,and the normalized root mean square error(NRMSE)ranged from 2.34%to 6.93%,1.38%to 9.89%,1.23%to 9.66%,and 1.31%to9.94%,and the model simulation accuracy was high.Under climate change,APSIM had good adaptability to the yield formation of dryland spring wheat under different tillage measures.2.By analyzing the characteristic of climate change in the study area for many years,it could be seen that temperature increase was an important climate change feature,and the maximums of rising range in average temperature anomalies were 2.05℃and 1.77℃respectively for the whole year and the whole growth period of spring wheat,precipitation was on a downward trend,with large interannual fluctuations,the positive anomaly of average value of the fluctuation range 55.11 mm,and the negative anomaly-52.82 mm,the solar radiation rose weakly.Correlation analysis showed that precipitation was highly significantly and positively correlated with yield,and sufficient light had saturated the demand for solar radiation for spring wheat production and its weak rise had less effect on yield relative to the effect of precipitation and temperature changes on yield.The diagnostic evaluation of the climatic suitability of dryland spring wheat growth based on APSIM model also reflected that light and temperature were basically above the more suitable level during the whole reproductive period of spring wheat,and precipitation was the main limiting factor.Climate change tends to warm and dry,through the regulation of tillage measures to curb water consumption of soil evaporation and soil and water loss,to maintain the available water supply of spring wheat,to improve water use efficiency,which would be an effective method for the dryland spring wheat production in response to climate change.3.Under climate change,simulation of dynamic changes in yield formation of spring wheat under different tillage measures showed that the number of continuous days of spring wheat from the germination stage of seed to organ formation stage(from sowing to flowering)decreased significantly,while sowing date had little influence on the number of growth continuous days during stage of grain formation(from flowering to maturity).Early sowing date of grain dry matter was slightly better than normal sowing date.The yield of normal sowing date(NSW)was higher than that of early sowing(ESW)and late sowing(LSW)with the difference ranging from 70.59 kg/ha~2 to 114.61 kg/ha~2 and 209.49 kg/ha~2 to 313.98 kg/ha~2.And grain protein content of normal sowing date was also highest.The effects of tillage treatments on the continuous days of growth and development were not significant under different sowing dates.The order of the beneficial degree of dry matter and yield of grains were shown as no tillage with straw cover(NTS)>conventional tillage with straw cover(TS)>no tillage(NT)>conventional tillage(T).The four tillage measures all showed the relationship between grain protein content and grain yield firstly increased and then decreased,and no tillage with straw cover(NTS)ensured yield and was more conducive to the improvement of grain protein content.Under climate change,normal sowing date and no tillage with straw cover(NTS)were the most beneficial to the efficient and top-quality production of dryland spring wheat.4.Simulation tests in groups with different straw cover gradients showed that spring wheat yield in the study area responded to climate change mainly in response to precipitation changes,precipitation always had a positive effect on yield and temperature had a negative effect on yield,and the interaction between precipitation and temperature was very obvious.Setting up a future climate change test scenario in the study area,the coupled simulation test of precipitation,temperature and straw cover further showed that precipitation had a positive effect on yield,temperature had a negative effect on yield,with the minimum yield when the increasing amplitude of temperature reached 2.8℃,and straw cover had a positive effect on yield.Compared with the case where only precipitation was increased,the improvement of average increase amplitude of yield for every increased 5%of precipitation and every increased 1000 kg/ha~2 of cover amount was from 21.57%to 22.25%,which had an increase of0.68%.Compared with the case where only temperature was increased,the improvement of average decrease amplitude of yield for every increased 0.5°C of temperature and every increased 1000 kg/ha~2 of cover amount was decreased from 6.44%to 5.93%,which had a decrease of 0.51%,and straw cover could contribute to the yield increase of precipitation.The tillage focused on the regulation of the amount of straw cover combined with a certain increase in yield.Considering the input-output efficiency,the optimal tillage control scheme for dryland spring wheat production under climate change in the study area was normal sowing date,no tillage with straw cover(NTS),with all straw returned to the field after harvest.In this study,the shuffled frog leaping algorithm was applied to the optimization of APSIM model parameters,and the model localization adaptation capability was further improved,and that broke through the key technical bottleneck of knowledge decision in intelligent production management of dryland spring wheat.Applying the APSIM model to the adjustment of tillage systems,it was confirmed that normal sowing date and no tillage with straw cover(NTS)was a reasonable tillage system for dryland spring wheat production under the warming and drying climate change in the study area,while focusing on combining the regulation of the amount of straw cover to increase the yield,and considering the input-output efficiency,the most suitable mulching practice was to return all straw to the field after harvest.更多还原