共查询到19条相似文献，搜索用时 78 毫秒
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１９９５－１９９６年度我省冬小麦生育期间农业气象条件总的来看是利大于弊；播前伏雨多，底墒足；冬前降温缓慢，光照充足，越冬正常；返青至抽穗期间，前期受抵温干旱的影响，使小麦各发育期普遍推迟，小麦进入生殖生长降价阶段降水量有所增加，降水适时集中，对中部，东南部麦区穗粒数的增加及大穗的形成有利，但南部主产麦区因前期干旱严重对穗粒数有定的影响。 相似文献
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通过对冬小麦穗粒结构与产量形成之间的内在关系进行分析,利用线性规划方法,构造产量最大目标函数,得出最优的产量穗粒结构. 相似文献
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云南昆明农业气象试验站 《气象》1978,4(6):28-28
早地小麦(简称地麦)在我省比例较大,约占全省小麦播种面积三分之二。长期以来,地麦一直是在秋季播种,由于受冬春干旱和霜冻灾害的影响,往往造成产量不高不稳。近年来,广大群众和农业科技人员在生产实践中把地麦秋播改为夏播,收到了良好的效果,是我省小麦生产上的一项突破。从多点试验情况来看,平均亩产200斤,最高达到了400斤。我站试验结果是有效穗25万,千粒重35—41克,穗粒数16— 相似文献
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通过对冬小麦穗粒结构与产量形成之间的内在关系进行分析，利用线性规划方法，构造产量最大目标函数，得出最优的产量穗粒结构。 相似文献
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利用自动站资料、雷达观测资料、NECP1°×1°再分析资料,采用相对于台风中心的移动坐标合成分析方法以及WRF模式的诊断分析,对2005年8月登陆浙江造成历史罕见特大暴雨的台风麦莎(Matsa)降水量分布特征进行分析,讨论与特大暴雨有关的台风结构变异。结果表明:①台风麦莎影响期间降水量的分布与通常热带气旋以螺旋雨带结构为主要特征的风雨分布特征显著不同,台风麦莎(Matsa)系统的右前、右后(第1、第2)象限出现了结构显著变异,对台风特大暴雨的特征落区分布有明显影响。②雷达与自动气象站资料分析揭示,在台风第1和第2象限发现有多个雨团重复生成和移动,它们与雷达回波观测到的强弱相间的中尺度上升和下沉气流相间区域相对应,是中尺度"降水细胞"频繁再生与移动的强烈发展区,对构成台风特大暴雨和灾害起重要作用。③具有再生能力的"暴雨细胞"特征结构的强烈发展区域出现动能的显著聚集,有利于台风中水汽在该区域的抽吸。台风系统的局部出现这样结构变异特征,对台风强降水落区的监测预报有重要指示意义。 相似文献
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《气象与环境学报》2017,(3)
利用2014年7月18—25日常规气象观测资料、美国国家环境预报中心再分析资料(National Centers for Environmental Prediction Reanalysis Project)和FY-2云图资料等,分别从环流形势、台风垂直结构、水汽输送及冷空气作用等方面,采用诊断分析方法分析台风"麦德姆"空心结构的形成和特征。结果表明:台湾岛、福建沿海山脉及武夷山脉等地形是影响台风"麦德姆"强度减弱和结构变化的重要因素,高低空涡度与散度场、水汽输送与水汽通量、地面冷空气入侵与干舌卷入等,均为台风"麦德姆"结构发生变化并出现"空心"现象的重要原因。对比相似的登陆台风可知,即使台风的路径和影响区域极其相似,不同台风的结构也存在较大差异,说明登陆台风的结构变化是极其复杂的。 相似文献
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本文利用甘肃省西峰市农业气象试验站非灌溉地冬小麦田间土壤水分资料、气候资料,分析了不同年型农田土壤水分的时空变化特征,从土壤水分平衡方程出发,讨论了冬小麦返青至成熟期间降水量、作物耗水量、渗漏量和土壤储水量变化各平衡分量的动态变化及其相互关系。对冬小麦产量与不同作物发育期的作物耗水量之间进行相关普查,结果表明影响小麦产量最显著的时段是拔节～孕穗期。分别运用物理统计和经验统计方法建立了冬小麦产量与作物耗水量的关系模型,认为后者模拟效果较好。 相似文献
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Studies of sensitivity of a dynamic model of grain crop productivity to soil-hydrophysical information 总被引：2，自引：0，他引：2
The relationship between a target function of a mathematical model of grain crop growth and development—yield—and variations in the soil and hydrophysical information expressed by variations in the soil water-retention function is considered. The function is approximated with a formula based on soil-hydrological constants. The soil profile in the model is represented by a three-layer structure. Each layer has its own agrohydrological characteristics: maximal hygroscopic moisture, wilting moisture, the least moisture capacity, and saturation moisture. The model AGROTOOL, identified from long-term data on field experiment at the Men’kovo experiment station of the Agrophysical Research Institute (the Leningrad region), is used to estimate the influence of variations in these sets on the barley and winter rye yield. It is demonstrated that the yield is most sensitive to variations in the least moisture capacity of the soil and has the least sensitivity to the change in the maximal hygroscopic moisture. 相似文献
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Petr Kolář Miroslav Trnka Rudolf Brázdil Petr Hlavinka 《Theoretical and Applied Climatology》2014,117(3-4):707-721
The paper aims to study the variability of spring barley and winter wheat yields, the most important crops in the Czech Republic, with respect to the variability of weather and climatic factors. Yields of both crops have been studied for 13 districts in Southern Moravia for the 1961–2007 period. From detrended series of spring barley and winter wheat yields, years with very low (lower than the mean minus a 2.5-multiple of the standard deviation) and extremely low (interval given by the mean minus a 1.5- and 2.5-multiple of the standard deviation) yields were selected. Years in which at least one of the districts had extremely low/very low yields were further analyzed. From 10 such years selected separately for spring barley and winter wheat, six of them agreed for both crops. Extreme years were studied using NUTS4-level yield data with respect to temperature, precipitation, the self-calibrated Palmer Drought Severity Index (scPDSI), snow cover, frost patterns, and the onset and duration of select phenophases. Extremely/very low barley yields in 1993, 2000, and 2007 were related to high April–June (AMJ) temperatures, low AMJ precipitation totals, and negative AMJ scPDSI (indicating drought) with an earlier onset of flowering and full ripeness and shorter intervals from tillering to flowering and from flowering to full ripeness compared to the entire 1961–2007 mean. As for extremely/very low winter wheat yields, in addition to the previously mentioned factors, winter patterns also played an important role, particularly the occurrence of severe frosts with a coinciding lack of snow cover and a long-lasting snow cover (in highlands), indicating that low yields are the result of not only one unfavorable factor but a combination of several of them. 相似文献
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Temperature thresholds and crop production: a review 总被引：2，自引：0，他引：2
Qunying Luo 《Climatic change》2011,109(3-4):583-598
Temperature thresholds for a range of crops from cereal crops to horticultural crops and to legum crops were identified through an extensive literature review. Identification of temperature thresholds provides a basis for quantifying the probability of exceeding temperature thresholds which is a very important aspect of climate change risk assessment. The effects of extreme temperatures on yield and yield components were then reviewed and summarised. Through these processes, critical phenophases were defined based on the sensitivity of crop yield and/or yield components to extreme high temperatures which were imposed on various phenophases. Information on the direction and degree of the impact of extreme temperature on yield/yield components can contribute to the improvement of crop models in which the effects of extreme temperature on crop production have not been adequately represented at this stage. Identification of critical phenophases at which crops yield and/or other economic characteristics are sensitive to extreme temperatures will help scoping appropriate adaptation options. 相似文献
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本文分析了黄淮海地区小麦生育期内不同时段的温度、降水与产量的关系,分别得到了不同类型的偏回归系数曲线。在此基础上,进行了不同季节温度升高对小麦产量的影响及温度、降水同时变化综合影响的模拟试验。结果表明,各地不同季节气候变暖对小麦产量的影响不同:北部、中部地区秋季、冬季变暖将导致增产,春季减产;而南部地区则秋季、春季将减产,冬季增产(河南南部略有不同)。降水量变化对各地各季气候变暖产量效应的迭加作用不同:北部、中部地区秋、冬季降水有利于增产,春季降水对减产略起缓解作用;南方各季降水过多均对小麦不利。总的说来,大部分地区若小麦生育期内气候变暖变湿,将有利于增产,但南部地区降水过多有不容忽视的负作用。 相似文献
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我国粮食产量气象分量的周期波动初探 总被引：1，自引：0，他引：1
本文应用功率谱、周期图和方差分析等方法探讨了全国及部分代表省(区)粮食单产中气象分量的中短周期波动。发现各地气象分量的谱分布基本相似,普遍存在4—6年及其倍数的周期波动。同时,各地表现又略有不同,由南往北周期逐渐变长。通过与农业气象热量因子以及粮食产量增减产年历史演变的周期波动的比较,似可初步推理为,热量因子的周期波动影响了气象产量的周期波动,从而导致作物产量的周期演变。这一初步推理为我国粮食产量的气象预测预报的基础研究和实践应用提供了参考依据。 相似文献
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根据盐城市的大、小麦产量，农技措施和气象资料，采用极限产量权重法组建大，小麦产量（ｙ）的预报模式：ｙ＝ｙｍ－ｙ农－ｙ灾－ｙ气或改写为：ｙ＝ｙｍ（１－（∑ａｉ＋∑Ｂｊ＋∑Ｃｎ））对盐城市大、小麦产量进行分段预报，经多年试报，结果与实产的相以误差均在５％以内。 相似文献
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海南岛农业气候生产力的估算 总被引：1，自引：0，他引：1
发挥气候资源的生产潜力,是农作物增产的有效途径。本文用Lieth法估算海南岛的农业气候生产力。光、热、水资源丰富的海南岛,植物的气候产量高,农作物的增产潜力至少为现在生产水平的一倍以上。水分是海南岛(尤其是西南部)农业产量的主要限制性因子。通过灌溉来补充所欠缺的水分(全岛平均每公顷需灌溉1778吨水),可期望达到最大气候产量。 相似文献