【作者】 李立；

【导师】 魏晓妹；

【作者基本信息】 西北农林科技大学 ， 水文学及水资源， 2010， 硕士

【摘要】 近年来,随着气温变暖,不仅加剧了降水的时空分布不均匀,对作物需水量的时空变化也有很大的影响,从而影响到农业用水的分配。另外,灌区农田水利工程的规划、设计和水量分配,引水、调水等决策,都需要精确的估算出灌区的作物需水量。因此,研究灌区气候变化对作物需水量的影响和作物需水量的时程变化,建立作物需水量的空间分布模型,对应对气候变化、调整农业结构,指导灌排工程规划,合理利用灌区水资源有重要意义。本文选择陕西省最大的宝鸡峡灌区作为研究对象,在分析气候对作物需水量影响的基础上,研究了灌区作物需水量的时空变异性,得到如下主要结论:(1)计算了灌区各站四种主要作物需水量,分析计算结果表明,近三十年来,作物需水量均呈波动增加趋势;四种作物需水量年内变化差异较大,冬小麦需水量四月份最大,玉米需水量七、八月较大,棉花需水量七月份达到最大,油菜3~6月需水较多。(2)利用Kendall秩次相关检验法和灰色关联分析法相结合,研究了气候变化对灌区作物需水量的影响。结果表明,气温的上升、蒸发能力和日照时数的增大是导致作物需水量增加的主要原因。其中,气温的上升对作物需水量的影响十分显著。(3)运用Morlet小波对灌区1981~2008年四种作物需水量进行了多时间尺度分析,结果表明,冬小麦需水量在3~5年尺度下出现过15次偏大期与偏小期的交替变换;玉米需水量在3年尺度下,出现偏大期和偏小期的交替15次,在六年尺度下出现过6次偏大期和偏小期的交替;棉花需水量在四年尺度下出现偏大期和偏小期的交替10次;油菜需水量在三年尺度下出现偏大期与偏小期交替16次,在五年尺度下出现偏大期与偏小期的交替变换8次。运用Spearman趋势检验分析了灌区四种作物需水量的变化趋势,结果表明,近三十年来各种作物的需水量均呈现出显著上升趋势,在此基础上建立了各种作物逐月需水量的灰色GM(1,1)模型进行拟合,拟合精度较高。(4)基于地统计学方法分析了灌区作物需水量的空间变异性。结果表明,四种作物的需水量中,棉花多年平均需水量最大,为636.8~683.4mm,玉米多年平均需水量最小,为469.6~511.7mm,冬小麦和油菜的多年平均需水量分别是490.1~538.1mm和549.7~607.9mm;四种作物需水量的空间变化规律各有差异,但存在一致性规律,均在在西南-东北方向上增大趋势显著;从东西方向上看,灌区西部宝鸡站附近作物需水量比较大,在眉县站附近作物需水量最小,往东部作物需水量逐渐增大,在咸阳站附近达到最大,从南北方向来看,均表现出由南到北的增大趋势。更多还原

【Abstract】 Recently, climate warming has aggravated not only spatial and temporal distribution of the precipitation unevenly, the crop water requirement has also stood a tremendous influence, affects allocation of agricultural water consumption thereby. Moreover, Planning and design of irrigation projects and water diversion project need estimating the crop water requirement in the irrigation district accurately. Therefore, study on the impact of climate change over crop water requirement, temporal distribution and building spatial distribution model of crop water requirement are very important for replying climate change, adjusting agriculture structure, guiding irrigation project plan and making use of water resource rationally.This paper took Baojixia irrigation district as the research region. On the basis of the influence of climate on crop water requirement, temporal and spatial distrbution of water requirement was researched in Baojixia irrigation district. The main conclusions were as follows:(1) Crop water requirement of four kinds of plants on each station in the irrigation district has been calculated. The results show that water requirement of plants all showed a trend of undulatory increase in the recent thirty years. The intraannual variation of crop water requirement for each plant has great differences, as winter wheat water requirement of April is maxima, maize water requirement of July and August is more, cotton water requirement of July is maxima, and rape water requirement from March to June is more than other month.(2) The impact of climate change over crop water requirement in the irrigation district was reseached using Kendall method and grey relational analysis mothod. It was shown that temperature rises, the increase of potential evaporation and the increase of sunshine duration are the main influence factors, leading to the increase trend of crop water requirement, in which the temperature is the most significant factor.(3) The multi-timescale analysis of water requirement of each plant in the irrigation district was studied from 1981~2008, according to Morlet wavelet theory. The result indicate winter wheat water requirement sequence shows fifteen times alternation of bigness priod and smallness on 3~5 years scale. Maize water requirement sequence shows fifteen times alternation of bigness priod and smallness on 3 years scale and six times alternation on 6 years scale. Cotton water requirement sequence shows ten times alternation of bigness priod and smallness on 4 years scale. Rape water requirement sequence shows sixteen times alternation of bigness priod and smallness on 3 years scale and eight times alternation on 5 years scale.The trend of the water requirement of each plant was reseached using spearman trend analysis. It was shown that the water requirement of every plant has increase trend. Basis on this trend, GM (1,1) model of crop water requirement was obtained, and the precision of this fitting is high.(4) Spatial variation of crop water requirement was studied basis on the geo-statistics. The result shows that cotton water requirement was the most in the four kinds of plants, as 636.8~683.4mm, maize water requirement was the minimum, as 636.8~683.4mm, the water requirement of winter wheat and rape were 490.1~538.1mm. Although the spatial variation rule of water requirement of four kinds of plants was different, all of crop water requirement show the obvious trend from southwest to northeast. From west to east, the crop water requirement nearby Baoji station in the western region was larger, the water requirement on Meixian station was smallest, to east, the crop water requirement enhanced gradually, reaching maximum nearby Xianyang station. From south to north, It is showed incease tendency.更多还原