Grain Yield Prediction of Henan Province Based on Spatio-temporal Regression Model

By using correlation analysis method,regression analysis method and time sequence method,we combine time and space,to establish grain yield spatio-temporal regression prediction model of Henan Province and all prefecture-level cities.At first,we use the grain yield in prefecture-level cities of Henan in the year 2000 and 2005,to establish regression model,and then taking the grain yield in one year as independent variable,we predict the grain yield in the fifth year afterwards.Taking the dependent variable value as independent variable again,we predict the grain yield at an interval of the same years,and based on this,predict year by year forward until the year we need.The research shows that the grain yield of Henan Province in the year 2015 and 2020 is 59.849 6 and 67.929 3 million t respectively,consistent with the research results of other scholars to some extent.

Planting density affected biomass and grain yield of maize for seed production in an arid region of Northwest China

Field experiments were conducted from 2012 to 2015 in an arid region of Northwest China to investigate the effects of planting density on plant growth, yield, and water use efficiency（WUE） of maize for seed production. Five planting densities of 6.75, 8.25, 9.75, 11.25 and 12.75 plants/m^2 were conducted in 2012, and a planting density of 14.25 plants/m^2 was added from 2013 to 2015. Through comparison with the Aqua Crop yield model, a modified model was developed to estimate the biomass accumulation and yield under different planting densities using adjustment coefficient for normalized biomass water productivity and harvest index. It was found that the modified yield model had a better performance and could generate results with higher determination coefficient and lower error. The results indicated that higher planting density increased the leaf area index and biomass accumulation, but decreased the biomass accumulation per plant. The total yield increased rapidly as planting density increased to 11.25 plants/m^2, but only a slight increase was observed when the density was greater than 11.25 plants/m^2. The WUE also reached the maximum when planting density was 11.25 plants/m^2, which was the recommended planting density of maize for seed production in Northwest China.

Modeling the Impacts of Soil Organic Carbon Content of Croplands on Crop Yields in China

This study quantified the impacts of soil organic carbon （SOC） content on the grain yield of crops using a biogeochemical model （DNDC, denitrification-decomposition）. Data on climate, soil properties, and farming management regimes of cropping systems were collected from six typical agricultural zones （northeast, north, northwest, mid-south, east and southwest regions of China, respectively） and integrated into a GIS database to support the model runs. According to the model, if the initial SOC content in the cropland was increased by 1 g C kg^-1, the crop yield may be increased by 176 kg ha^-1 for maize in the northeast region, 454 kg ha^-1 for a maize-wheat rotation in the north region, 328 kg ha^-1 for maize in the northwest region, 185 kg ha^-1 for single-rice in the mid-south region, 266 kg ha^-1 for double-rice in east region, and 229 kg ha^-1 for rice and wheat rotation in southwest region. There is a great potential for enhancing the crop yield by improving the SOC content in each region of China.

Gray Connection Analysis on Grain Yield and Agricultural Fundamental Infrastructure

Although the agriculture in Heilongjiang Province has develope poor historical basis and differences between rural and urban institutional fa d ct effectively in recent years, due to issues such as ors, the backward of the agricultural fundamental infrastructure is always the major obstacle in rural economic development of Heilongjiang Province, which prevents the advantage of agricultural production from being fully developed, leading to the increase rate of the grain yield to grow slowly. The backward reflects in the following aspects, the serious aging of water facilities, insufficient agricultural machinery and equipment, low leve of rural roads, lacking of research equipment, shortage of ecological protection facilities, and so on. Based on the latcr data of Heilongjiang Province, this paper analyzed the connection between agricultural fundamental infrastructure and grain yield by using the gray connected model, differentiated primary rural fundamental infrastructure from the secondary one, and provided some suggestions to develop rural areas

The General and Structural Effect of " Four Agricultural Subsidies " on Grain Yield: Empirical Analysis of Chongqing City

On the basis of empirical data concerning " four agricultural subsidies" in Chongqing City,we establish panel data model to analyze the general effect of " four agricultural subsidies" on grain yield,and the structural effect of " four agricultural subsidies" on grain yield. Based on the F-test and Hausman test,we estimate the model using GLS or FGLS method. The results show that " four agricultural subsidies" have significant positive effect on grain yield; the structural effect of " four agricultural subsidies" on grain yield is different (comprehensive subsidies for means of agricultural production has the strongest effect on grain yield,followed by subsidies for promotion of improved variety of seed; the effect of subsidies for purchase of agricultural machinery on grain yield is not significant) . Therefore,governments at all levels should continue to strengthen the support efforts in " four agricultural subsidies" ,and continually optimize the structure to increase grain yield.

不同秸秆还田技术模式对冬小麦强弱势粒灌浆特性的影响

为揭示砂姜黑土区不同秸秆还田技术模式对冬小麦籽粒灌浆进程的影响,该研究基于农业农村部华东地区作物栽培科学观测站15a的长期定位试验,设置单季小麦秸秆全量粉碎覆盖还田(T1)、小麦秸秆全量粉碎覆盖还田+玉米秸秆全量粉碎翻埋还田(T2)、单季玉米秸秆全量粉碎翻埋还田(T3)和小麦玉米秸秆全年不还田(CK)4种不同秸秆还田技术模式,采用Richards方程模拟冬小麦籽粒灌浆过程,研究不同秸秆还田技术模式对冬小麦强弱势粒灌浆特征参数的调控效应。结果表明:1)相较于秸秆不还田,秸秆还田处理能提升冬小麦强、弱势粒的籽粒体积、千粒质量和产量,T1、T2、T3处理下强势粒千粒质量和籽粒产量较CK分别显著提升11.02%、10.63%、13.75%和16.28%、14.29%、13.94%,弱势粒千粒质量和籽粒产量较CK分别显著提升9.73%、6.64%、7.57%和19.24%、23.25%、11.50%。Richards方程能极显著模拟不同秸秆还田技术模式下冬小麦籽粒灌浆过程,拟合方程决定系数(R^(2))均在0.997以上。2)对冬小麦强势粒,秸秆还田可延长小麦强势粒灌浆时间,主要通过缩短灌浆渐增期持续时间和提高其灌浆速率,延长灌浆缓增期的持续时间来提升强势粒千粒质量。其中T1、T3处理下冬小麦强势粒灌浆持续时间较CK分别延长2.137 d和4.443 d,T1、T2处理下强势粒单粒最大灌浆速率较CK分别显著提高了7.81%和12.26%。3)对冬小麦弱势粒,T1处理下弱势粒灌浆持续时间较CK延长1.477 d,T1、T2、T3弱势粒单粒最大灌浆速率较CK分别显著提升16.46%、22.69%和17.13%。该研究表明秸秆全量还田可提升砂姜黑土区冬小麦籽粒库容和籽粒灌浆速率,最终增加粒质量。研究可为砂姜黑土区秸秆资源的高效利用提供理论指导和技术支撑。

中国耕地面积-粮食产量重心迁移轨迹特征及空间错位关系

为了探究粮食资源和耕地利用效率的协调统一,利用2000—2019年中国耕地面积和粮食产量数据,以省域为研究对象,基于重心模型和空间错位指数,系统分析全国耕地面积、粮食产量重心迁移轨迹特征及空间错位关系。结果表明:研究期内耕地面积重心与粮食产量重心变化方向不尽相同,耕地面积重心从河南省博爱县向东北移动,而粮食产量重心则先从河南省舞阳县向东北后再向东向平移;全国的粮食产量和耕地面积主要集中在中水平区和中低水平区,且由东到西呈现正向错位到负向错位的分布特征;耕地面积和粮食产量受资源禀赋影响较大,但经济发展水平、人口、降水量和积温水平等因素也具有一定的推动作用。

Application of an Economy-Climate Model to Assess the Impact of Climate Change

An interdisciplinary investigation was conducted to assess the impact of climate change on grain yields using an economy-climate model （C-D-C）. The model was formulated by incorporating climate factors into the classic Cobb-Douglas （C-D） economic production function model. The economic meanings of the model output elasticities are described and elucidated. The C-D-C model was applied to the assessment of the impact of climate change on grain yields in China during the past 20 years, from 1983 through 2002. In the study, the land of China was divided into eight regions, and both the C-D-C and C-D models were applied to each individual region. The results suggest that the C-D-C model is superior to the classic C-D model, indicating the importance of climate factors. Prospective applications of the C-D-C model are discussed.

Modeling of Different Irrigation Methods for Maize Using AquaCrop Model: Case Study

Modeling of irrigation methods is one of the most important techniques that contribute to the future of modern agriculture. This will conserve water as water scarcity is a major threat for agriculture. In this study, AquaCrop model was used to model different irrigation methods of maize in field trails in Al-Yousifya, 15 km Southwest of Baghdad. Field experiments were conducted for two seasons during 2016 and 2017 using five irrigation methods including furrow, surface drip and subsurface drip with three patterns of emitter depth (10, 20 and 30 cm) irrigation. AquaCrop simulations of biomass, grain yield, harvest index and water productivity were validated using different statistical parameters under the natural conditions obtained in the study area. For 2016 and 2017 seasons, results of R2 were 0.98 and 0.99, 0.99 and 0.99, 0.99 and 0.97, and 0.8 and 0.73 for biomass, grain yield, harvest index and water productivity, respectively. The study has conducted that simulation using AquaCrop is considered very efficient tool for modeling of different irrigation applications for maize production under the existing conditions in the central region of Iraq.

Scale effect and geometric shapes of grains

The role-of-mixture approach has become one of the widely spread ways to investigate the mechanical properties of nano-materials and nano-structures, and it is very important for the simulation results to exactly compute phase volume fractions. The nanocrystalline （NC） materials are treated as three-phase composites consisting of grain core phase, grain boundary （GB） phase and triple junction phase, and a two-dimensional three-phase mixture regular polygon model is established to investigate the scale effect of mechanical properties of NC materials due to the geometrical polyhedron characteristics of crystal grain. For different multi-sided geometrical shapes of grains, the corresponding regular polygon model is adopted to obtain more precise phase volume fractions and exactly predict the mechanical properties of NC materials.

胡麻籽粒产量形成对干旱胁迫的响应及其模拟模型研究

为了进一步研究胡麻籽粒产量形成对干旱胁迫的响应,采用大田遮雨棚控水法模拟胡麻干旱胁迫,依据2019—2020年甘肃省定西市西巩驿镇的实际产量,以3个品种陇亚12号、陇亚8号、晋亚11号为材料,在苗期、枞行期、现蕾期、青果期,设置正常供水、中度干旱、重度干旱3个不同程度处理,利用气象数据、土壤数据、品种性状等构建胡麻产量响应干旱胁迫模型,并对该模型进行检验。结果表明:(1)APSIM模型模拟胡麻产量及单株蒴果数、每果粒数、单株粒质量、千粒质量的均方根误差RMAE分别为43.07 kg/hm^(2)、0.80个、0.52粒、0.03 g、0.54 g,决定系数R^(2)分别为0.82、0.78、0.83、0.81、0.83,说明模型具有较好的拟合性。(2)随着干旱胁迫的增加,不同生育时期的胡麻株高、茎粗、干物质积累量等逐渐下降,其中现蕾期的降幅最明显,对水分需求较大;在重度干旱胁迫下,胡麻各产量因子及籽粒产量与对照组差异性显著,陇亚12号产量较CK降低31.9%,陇亚8号产量较CK降低30.2%,晋亚11号产量较CK降低37.1%。关联度分析可知,影响胡麻籽粒产量的主导因子是千粒质量。相关性分析结果显示,不同生育时期的干物质积累量在干旱胁迫下与产量及构成因素有显著正相关关系。现蕾期对土壤缺水比较敏感,在此时期精准灌溉,有利于胡麻生长发育和干物质积累,促进千粒质量,提高籽粒产量,为实现胡麻合理灌溉和高效增产奠定了基础。

深蓄储水灌溉对冬小麦籽粒灌浆及生长产量的影响

深蓄储水灌溉一方面可以充分发挥土壤水库作用,同时也可以将农田作为地下水回灌补给区,增加雨洪资源利用率。以“小偃22”为供试品种、雨养(CK)为对照,设置80 cm(D80)、120 cm(D120)、140 cm(D140)、160 cm(D160)和180 cm(D180)5个深蓄储水深度处理,分析不同处理对冬小麦干物质累积分配、产量和籽粒灌浆进程的影响。结果表明:各处理较CK分别增产8.9%(D80)、24.7%(D120)、31.0%(D140)、17.9%(D160)和9.9%(D180);深蓄储水灌溉提高了籽粒在干物质中的分配量和占比,其中D140处理籽粒分配比例较CK提高了2.46%;Logistic方程能较好地拟合不同深蓄储水深度冬小麦籽粒灌浆进程,拟合方程决定系数均大于0.99,深蓄储水处理较对照提高了平均灌浆速率,最大灌浆速率出现时间延长了1.65~3.32 d。深蓄储水灌溉有利于冬小麦籽粒灌浆及产量形成,本研究可为充分利用雨洪资源改善农田地下水环境、实现作物高产提供参考。

基于BP神经网络对云南省粮食产量的预测模型

基于BP神经网络建立云南省粮食产量预测模型,分析有关文献,最终选择农业机械总动力、有效灌溉面积、农用化肥施用折纯量、农村用电量、农药使用量、粮食作物播种面积、农用柴油使用量和受灾面积等8个指标作为输入变量,粮食产量为输出变量。首先以云南省1993—2016年的粮食产量及8个粮食产量影响因素等数据,搭建BP神经网络预测模型,预测2017年、2018年和2019年的粮食产量。试验结果表明,基于BP神经网络预测模型在训练阶段,相对误差绝对值基本小于1%;在验证阶段,预测2017年、2018年和2019年的相对误差分别为1.84%、3.25%和2.86%,误差率均控制在5%以为,说明该模型具有很好的预测效果,能够有效地对粮食产量进行预测,并为粮食产量的预测提供了一种新的方法。

基于农业灾情数据的贵州省粮食单产灾损估算模型

【目的】探明贵州省粮食气候减产量与灾情程度的关系,为贵州省防范农业自然灾害风险和科学预测粮食单产提供决策依据。【方法】利用2010—2020年贵州省粮食灾情统计数据,计算干旱、洪涝、风雹、低温的受灾率、成灾率及绝收率,并用灰色关联法评价各灾种及灾害程度对全年粮食及水稻、玉米、马铃薯气候单产的影响,运用多元回归方法分析粮食气候减产量与灾情的关系,构建基于灾情的粮食单产灾损估算模型。【结果】从发生频率看,干旱为贵州省2010—2013年主要的农业气象灾害,2014年起逐步由旱转涝;发生程度中等、范围较广的干旱及程度较重、局地性强的低温灾害是造成贵州省粮食作物减产的主要灾害。构建了粮食气候减产量(ΔY_(w))与总受灾率(Kts)、总成灾率(Ktc)、总绝收率(Ktj)的灾损评估模型:ΔY_(w)=189.2Kts+4490.6Ktc+50.0Ktj+85.2(R^(2)=0.760,P<0.01),通过模型估算得到的模拟单产与实际单产的相关性极显著(P<0.01),且误差在合理范围内。【结论】贵州省粮食总受灾率、总成灾率和总绝收率与气候减产量呈极显著正相关关系,即灾害程度越高,气候减产量越大,粮食因灾损失也越大;基于灾损的粮食单产估算模型可估算当年粮食单产。

基于LMDI的吉林西部地区粮食产量变化的影响因素解析

吉林西部地区是吉林省粮食生产的增长极,是促进吉林省粮食产能持续稳定增长的重要保障区域。本研究应用LMDI模型系统分析了2000—2019年吉林西部地区粮食产量变化及其影响因素,量化了粮食播种面积、种植结构、粮食单产对粮食产量变化的效应大小,并分析其时空变化特征。结果表明,2000—2019年吉林西部地区粮食产量增加825.02万t,播种面积效应起到明显的正向作用,增产452.33万t,结构效应增产141.38万t,单产效应增产231.32万t,贡献占比分别为54.83%、17.14%和28.04%。从时间变化上看,面积效应2009年出现最高值194.94万t,2017年出现最低值-74.86万t;结构效应2004年出现最高值74.54万t,2002年出现最低值-21.66万t;单产效应在时间上波动强烈,最高值出现在2005年(407.47万t),最低值出现在2009年(-429.69万t)。在空间分布上,面积效应最高值为长岭县,最低值在宁江区;结构效应最高值在扶余市,最低值在通榆县;单产效应最高值在前郭县,最低值在洮北区。受脆弱生态环境约束,未来吉林西部作为资源脆弱地区应谨慎扩大耕地面积,以优化种植结构、提升粮食单产为主,实现粮食长期可持续增产。

北方地区不同等级干旱对春玉米产量影响

北方地区是中国主要的玉米种植区，在中国玉米总产和播种面积中占有较大比例，同时也是中国易发生干旱的地区，北方地区干旱常态化严重制约着该地区玉米的稳定发展。该文基于北方地区14个省（市、自治区）217个气象台站1961－2010年的逐日气象数据以及作物、土壤和田间管理资料，依据春玉米生长季内降水量并以100 mm为间隔将全区划分为6个区域（Ⅰ～Ⅵ），选取作物水分亏缺指数为农业干旱指标，基于验证后的农业生产系统模型（agricultural production systems simulator，APSIM），明确了各生育阶段不同等级干旱对春玉米产量的影响。研究结果表明，北方地区干旱造成春玉米减产率在空间上呈由西向东下降趋势，降水的空间分布直接导致了灾损程度在各区的差异，其中西部灌溉绿洲农业区雨养种植春玉米干旱风险非常大，需大力发展节水灌溉，而东部雨养农业区自然降水已基本满足春玉米生长发育需要，干旱对春玉米产量影响较小，在模拟过程中很难准确的反映出旱级对产量造成的差异影响。春玉米在拔节—抽雄阶段发生干旱会对产量造成比较严重的影响，该阶段4个等级干旱造成春玉米减产率的四分位区间分别为特旱（20.1%～33.6%）、重旱（12.0%～20.3%）、中旱（6.3%～15.2%）、轻旱（4.7%～11.6%）。

运用AMMI模型分析水稻多点双列杂交试验 Ⅰ.组合的丰产性、稳产性和适应性分析

用四川省水稻育种攻关组“八五”后期育成的一批不育系和恢复系（同时加对照珍汕９７Ａ和明恢６３）按不完全双列杂交配制２０个组合，于１９９６年分别在成都、绵阳、重庆和泸洲进行试验，运用ＡＭＭＩ模型对参试组合的产量进行了分析。结果表明：有９个组合的平均产量超过对照汕优６３，增产幅度为０．０３％～４．０６％，占参试组合的４２．１１％；组合稳定性评价很重要，基因型与环境的互作达极显著水平，互作效应为基因型效应的二倍；ＡＭＭＩ模型的前两个主成分解释了８３．３５％的交互作用信息；珍汕９７Ａ／７３４、Ｋ４２Ａ／７３４和辐７６Ａ明恢／６３表现丰产而稳产，辐７６Ａ／７３４和辐７６Ａ／生５丰产而不稳产，辐７６Ａ／成恢１４９、台九Ａ／生５和Ｋ４２Ａ／成恢１４９则稳产而不丰产，其余组合既低产又不稳产。建议推荐辐７６Ａ／７３４、Ｋ４２Ａ／７３４、珍汕９７Ａ／７３４、辐７６Ａ／生５等参加省级区试；辐７６Ａ／生５同时在绵阳、珍汕９７Ａ／１３４８在重庆、Ｋ４２Ａ／明恢６３在成都参加市级区试或示范。

陕西省干旱灾害的农业风险评估

分析了陕西干旱发生的时空规律，以缺水率划分干旱标准，评价陕西各季农业干旱状况，并对1949～1990年共42a粮食产量序列进行滑动平均模拟，以粮食减产百分率评估全省干旱灾害等级，得出干旱损失评估模式，使陕西干旱灾害的评估由定性到定量，为其它灾害的定量评估提供了经验。

基于DSSAT模型的氮肥管理下华北地区冬小麦产量差的模拟

为了评价氮肥管理对华北地区冬小麦产量差的影响,利用大田试验数据和田间调查的方法,应用DSSAT模型分析了吴桥不同氮肥水平下冬小麦多年平均可获得产量及产量差,并研究了不同地块产量差和氮肥农学效率差的分布。结果表明,不同地块冬小麦产量差异显著,但产量变异较小,地块间施肥水平存在明显差异,且变异较大。模型分析确定222 kg/hm2为最佳施氮肥量,对应的最大可获得产量为7 618 kg/hm2,地块产量与最大可获得产量有较大差距,当地冬小麦产量具有一定的提升空间。75%的农户地块的施氮量高于最佳施氮量,且氮肥农学效率普遍偏低。因此,生产中应优化氮肥管理方案,适当减氮并调整施肥时期和改进技术,提高氮肥农学效率,以实现冬小麦生产高产高效。在保障国家粮食安全和保护自然环境双重压力的背景下,通过合理的氮肥管理来缩减冬小麦产量差对提高中国粮食总产及保持农业可持续发展具有重要的意义。

农田土壤有机碳含量对作物产量影响的模拟研究

【目的】探求土壤有机碳含量对作物产量的影响,以期为保障国家粮食安全和耕地持续利用与管理提供决策依据。【方法】利用农田生态系统生物地球化学模型DNDC,针对中国东北、华北、西北、中南、华东和西南6个典型农业区域,每个区域选择各自典型的种植模式和现行的农田管理措施,在各自特定的土壤和气候条件下,输入并运行模型,模拟考察在其它投入条件不变的情况下,改变土壤有机碳本底值对作物产量的影响。【结果】当土壤有机碳含量(SOC)增加1g C.kg-1,东北地区玉米产量可增加176kg·hm-2;华北地区夏玉米与冬小麦轮作,产量可增加约454kg·hm-2;西北地区春玉米产量约可增加328kg·hm-2;中南地区单季水稻产量可增加约185kg·hm-2;华东地区双季稻产量可增加约266kg·hm-2;西南地区水稻与冬小麦轮作产量可增加约229kg·hm-2。【结论】在其它投入既定的条件下,全国各地区均存在通过提高耕地土壤有机碳含量来增加作物产量的潜力。保持较高水平的土壤有机碳含量对节本增效具有十分明显的作用。