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以2007年1月至2019年12月新疆和全国棉花平均价格月度数据为研究对象,运用X12季节调整法、Hodrick和Prescott滤波法,对新疆棉花价格总体波动特征和规律进行了分析。结果显示:新疆棉花价格和全国棉花平均价格的季节性和周期性波动特征一致,在每年3月份左右升至最高点后开始回落,至9月份左右触底,之后逐渐上升,到次年2-3月份价格升至最高点,每年循环往复;2007-2019年新疆棉花价格经历了3个完整的周期,周期平均为42个月,目前进入新一轮周期。从长期趋势来看,新疆棉花价格波动整体呈现非线性上升趋势。新疆棉价变动与全国棉价(包括新疆)变动影响因素基本一致,短期内会受到政策、成本、国际棉价、金融等其他外部因素的影响。在新冠肺炎疫情和常态化疫情防控导致国内外需求疲软背景下,经济发展的不确定性增强,棉花价格的波动率将会显著上升,新疆棉花价格也将会受到影响。因此,提出持续加强新疆优质棉基地建设、持续推进新疆棉花生产供给侧结构性改革、强化棉花市场监管与价格预警、探索新型补贴方式等建议。 相似文献
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对2002年7月―2014年5月中国棉花价格波动特征进行研究,表明棉花价格长期波动周期为7年。利用ARCH族模型分析表明中国棉花价格异方差效应不显著、波动具有显著的集簇性、非对称性,棉花市场没有高风险高回报的特征。引起棉花波动的原因为生产成本、天气、政策、进口、库存等,其中2014年实施的目标价格补贴政策是引起当下及后期棉花价格波动的主要原因且有拉低我国棉价回归市场的趋势。 相似文献
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基于马尔科夫链的棉花价格预测 总被引:1,自引:0,他引:1
针对国内与国际棉花价格预测问题进行研究,将棉花价格波动过程视为马尔科夫过程,应用马尔科夫模型预测国内和国际棉花价格。对棉花价格的历史数据进行了马氏性检验,利用数理统计方法得到其马尔科夫链状态转移概率,然后以2011―2013年国内和国际棉花价格在未来一段时间内波动区间及波动周期为应用面,分别对国内2014年棉花月度价格和2015年棉花逐日价格、国际棉花月度价格进行预测并分析,最后分析了2015年棉花价格走势。结果表明马尔科夫链能够较好地预测国际和国内棉花价格,对逐日价格的预测误差比月度价格更小,对国内价格的预测误差比国际价格更小。 相似文献
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中国棉花价格波动特征及趋势分析 总被引:1,自引:1,他引:0
通过计算1999-2011棉花年度中国棉花价格指数CCIndex 328的波动指数、波动系数等价格波动指标,分析了中国棉花价格的波动特征,利用H-P滤波将中国棉花价格指数的时间序列分解成长期趋势分量与短期周期分量,并对周期分量进行频谱过滤。结果显示,流通体制改革以来,中国棉花价格具有波动性、季节性特征,从中长期趋势分析认为未来几年内国内棉花价格可能重新进入小幅变动阶段,短期内棉花价格可能出现反弹。 相似文献
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棉花生产比较效益是棉农收益、棉花生产布局和产业发展的主要影响因素。基于1989―2016年面板数据,分析了我国棉花主产区生产比较效益及其影响因素和作用方向。结果表明:(1)西北内陆棉区生产比较效益最优,黄河流域棉区次之,长江流域棉区较低。(2)棉花生产比较效益变化受棉花播种面积、产量、国家政策、价格和竞争作物等多重因素影响,且各因素影响程度和作用方向存在差异。(3)棉花价格和政策对主产区棉花生产比较效益的影响最显著,自然灾害、机械化水平、植棉收入占比、棉经产值比等较显著。鉴于此,提出完善棉花生产支持政策,健全棉花价格波动预警和发布机制,及时把握各因素的影响程度和差异等建议。 相似文献
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我国棉价运行的特点及影响因素浅析 总被引:1,自引:0,他引:1
棉花是涉及农业和纺织工业两大产业的商品,是全国1亿多棉农收入的主要来源,因此对我国棉花价格运行特点和影响因素分析有重要的意义。1我国棉价运行的特点1.1棉价波动幅度比较大。我国棉花价格在70年代末、80年代末上涨幅度比较快,90年代初达到每吨2000元;90年代后,棉价出现了大幅上涨、调整和下跌的过程。1999年,我国棉价只有7400元·吨-1,2000年上升到13500元·吨-1;2002年下降到7200元·吨-1,2003年上升到17800元·吨-1,波动幅度最大可达10000元·吨-1。1.2棉价波动呈现出明显的周期性。自1999年中央放开棉花价格以来,我国棉价运行有明显… 相似文献
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《Plant Production Science》2013,16(2):189-198
AbstractGrain number per spike of wheat is lower in early sowing than in the conventional standard cultivation in Yamaguchi, Prefecture, Japan. Components of the grain number per spike in five cultivars were analyzed with respect to temperature during the spike development period throughout three growing seasons 2001/2002, 2002/2003 and 2003/2004 to find the cause of the problem of early sowing cultivation. The plants sown in early-October and late-November were called the early sown group and the standard group, respectively, in the following. Three of the five cultivars, Hokushin, Akitakko and Nanbukomugi, showed a strong winter habit, which requires very cold temperatures for spike differentiation. The other two cultivars, Iwainodaichi and Airakomugi, had a moderate winter habit. Grain number per spike and grain yield were decreased by early-sowing (compare with the standard group) in almost all cultivars throughout the three growing seasons. The three cultivars which had a strong winter habit had fewer spikelets per spike in the early-sown group than in the standard group. The other two cultivars which had a moderate winter habit had fewer grains per spikelet in the early-sown group. The higher the temperature during the spikelet formation phase, which is from flag leaf initiation to terminal spikelet initiation, the higher the number of spikelets per spike in the standard group. The spikelet number per spike in the early-sown group increased with the increase in productive tillers under fertile conditions. Such conditions also increased the grain number per spike. 相似文献
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《Journal of Crop Improvement》2013,27(2):415-432
Summary This paper reviews the effects of allelopathic interactions in agroecosystems in Spain on plant physiological activity and their ecological advantages. The phenological stage of growth of donor plants and the effective allelochemicals in the soil solution while studying the role of phenolic compounds were highlighting. Finally possible future prospects and conclusions regarding weed control by allelochemi-cals under integrated crop management strategies are discussed. 相似文献
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Summary Diurnal changes in net photosynthetic rate were measured in a furrow-irrigated potato crop and in a riverbed crop where the
water table was always maintained at 20–28 cm from the soil surface. In the irrigated crop, the photosynthetic rate during
mid-afternoon was about half the peak rate observed at noon. This reduction was accompanied by a near tripling of stomatal
resistance, a 45% reduction in transpiration, and a 5-fold increase in the difference between leaf and air temperatures. No
such changes were observed in the riverbed crop where the photosynthetic rate remained nearly constant at about 0.9 mg m−2 s−1 between 9 a.m. and 4 p.m. Tuber yield in the riverbed crop was about 30% higher than in the irrigated crop. 相似文献
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以翔实的资料对2009年中国稻米生产、消费、进出口、供求平衡、库存、价格走势、购销政策和国际稻米供求等情况进行了全面地分析,对影响2010年稻米市场价格走势的各种因素进行了深入研究,并在此基础上对2010年我国稻米市场价格走势进行了预测,结论是我国稻米价格仍呈上行趋势。 相似文献
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Corné Kempenaar Thomas Been Johan Booij Frits van Evert Jean-Marie Michielsen Corné Kocks 《Potato Research》2017,60(3-4):295-305
Precision agriculture is a farming management concept based on observing, measuring and responding to inter- and intra-field variability in crops. In this paper, we focus on responding to intra-field variability in potato crops and analyse variable rate applications (VRAs). We made an overview of potential VRAs in potato crop management in The Netherlands. We identified 13 potential VRAs in potato, ranging from soil tillage to planting to crop care to selective harvest. We ranked them on availability of ‘proof of concept’ and on-farm test results. For five VRAs, we found test results allowing to make a cost-benefit assessment. These five VRAs were as follows: planting, soil herbicide weed control, N side dress, late blight control and haulm killing. They use one of two types of spatial data: soil maps or biomass index maps. Data on costs and savings of the VRAs showed that the investments in VRAs will pay off under practical conditions in The Netherlands. Savings on pesticide use and N-fertilizer use with the VRAs were on average about 25%, which benefits the environment too. We foresee a slow but gradual adoption of VRAs in potato production. More VRAs will become available given ongoing R&D. The perspectives of VRAs in potatoes are discussed. 相似文献
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体细胞无性系变异是一种重要的细胞工程育种技术,其应用于棉花育种的前提是建立高效的组织培养诱导再生植株体系.本文简要综述了棉花离体诱导植株再生研究的现状,重点讨论了棉花体细胞无性系变异的表现、利用方法及机理,提出了当前研究存在的问题并对今后的研究进行了展望. 相似文献