产量变化的主要成份分析

利用历史产量序列重构二维时变矩阵进行自然正交分解，得到了3种影响产量变化的主要成份。通过分析发现，这些主要成份不仅包括能反映生产力变化的趋势分量和能表达气候影响效果的短期振荡分量，还发现了一种由气候决定的趋势作用分量，对产量有着不可忽视的影响。这些分量相互独立，无预先设定的函数模型，为产量分析和预报提供了较为客观和完备的历史变动序列，对提高产量预报精度有着重要意义。     

NOAA/AVHRR资料在低纬高原小春作物估产中的初步应用

利用气象卫星NOAMAVHRR1、2通道遥感光谱资料在GPS和GIS的支持下，进行遥感绿度数字图像的目视解译和统计解译，计算绿度值概率密度。结合地面农情监测资料和同期气候资料，预测低纬高原(曲靖市为例)小春作物增减产趋势，建立遥感估产模型，结果表明1～3月是小春作物信息提取、长势动态监测的最佳时期，3月是小春作物产量预报的最佳时欺。针对卫星遥感资料短的特点，采用时间和空间结合扩大样本法效果较好。     

基于历史产量丰歉影响指数的黑龙江省水稻产量动态预报

水稻是黑龙江省主栽作物之一,开展水稻产量动态预报对黑龙江省粮食生产具有重要意义。利用黑龙江省水稻主产区产量资料、发育期资料、日最高气温、日最低气温、日降水量和日照时数等资料,根据历史年水稻产量丰歉气象影响指数,建立黑龙江省水稻产量丰歉趋势动态预报模型。另外,采用相关分析的方法,确定影响产量的关键气象因子,建立相应的产量预报模型,对产量丰歉趋势动态预报模型进行修订。通过对1997-2006年水稻产量进行动态预报,结果表明,5月31日、6月30日、7月31日和8月31日预报的水稻产量增减趋势的预报正确率平均为90%、70%、90%和80%,产量预报准确率为84%、90%、94%和93%,预报准确率较高,能够满足业务服务的需要。     

作物产量灰色马尔柯夫链预测模型

以黑龙江垦区１９４９－１９９２年小麦单产资料为例，用灰色系统ＧＭ（１，１）动态预测模拟和预测趋势产量，用马尔柯夫链动态预测模型预报气象产量，从而组合一套完整的作特意一灰色马尔柯夫链预测模型。以此模型对黑龙江垦区小麦单进行预测，其结果均怀实况基本相符。     

趋势—状态预测方法及其在农业上的应用

提出一种趋势－状态预测方法，可较好地解决既有趋势又具有较大波动性数据序列的预测问题。与现有预测方法相比，它具有计算简单，精度高的特点，采用其对浙江省蚕茧产量进行预测分析表明，效果良好。     

基于产量阶段的河南省夏玉米灰色——马尔柯夫预测模型

针对较长产量序列纵向及横向可比性较差的问题 ,提出用划分产量阶段的方法进行分段处理。用 GM(1,1)灰色模型分段模拟预测河南省夏玉米单产 ,根据相对气象产量划分产量状态 ,再用马尔柯夫模型转移概率预测系统未来发展方向并修正前者的预报结果。通过模拟和预报 ,准确率都有所提高     

基于BP滤波的Fourier模型在粮食产量预测中的应用

本文尝试将经济学中的功率谱分析（BP滤波）与统计学中的Fourier模型相结合,先利用BP滤波选出对气候产量波动影响较大的周期,再对这些周期建立Fourier模型来拟合气候产量;同时运用多项式模型拟合趋势产量,并用滞后模型对残差进行修正,以提高粮食单产预测的精确度。利用1961-2000年粮食单产序列数据,分别采用Fourier方法和多项式滞后方法、BPNN法和灰色模型法建立模型,以2001-2012年粮食单产数据进行拟合检验。将这3种方法拟合结果进行比较。结果表明,本文引入的模型通过0.01水平的显著性检验且相对误差均在5%以下,利用模型对粮食单产进行中长期预测的结果表明,2013-2017年中国粮食单产将稳定在6018.6～6466.7kg·hm?2。BP神经网络法模拟的粮食单产虽然拟合相对误差较小,但模型不能得到直观解释,在预测时存在一定的随机性;灰色模型模拟的粮食单产相对误差高达35%,与实际产量存在较大差异。研究结果反映出Fourier模型和多项式滞后模型在粮食产量预测中,其精确度更高且更直观,能够用以预测未来粮食单产以及未来气候变化对粮食单产的影响。     

三江平原地区粮食产量预报模型研究

运用聚类分析方法依据农业气候条件对三江平原地区进行分类,在此基础上,选取玉米、大豆、小麦三种作物产量的预报点,建立了作物产量的定性和定量预报模型,即年景趋势预报模型、逐步回归周期分量预报模型和多层递阶预报模型。统计检验和实际预报结果表明所得到的预报模型是有实际意义的。     

冬小麦产量气象生物学模式研究

<正> 本文将冬小麦产量的时间序列分解为生产水平与气候生产力两个分量,通过对气候生产力的模拟,将影响产量的气象信息定量化、模式化。其结果,不仅可作为小麦大面积生产栽培和趋利避害的参考依据,而且可以在小麦生育的几个主要阶段对产量进行不同时效的气象预测预报。一、产量的趋势模拟本文采用安徽省淮北平原阜阳县1950-1982年冬小麦大面积单产资料。在产量序列中由于1960、1961两年出现不寻常的波折,     

时间序列分析在土壤墒情预测中的应用研究

土壤水分的动态模拟是土壤墒情监测及预报的重要内容,采用时间序列的线形模型进行土壤水分时间序列的拟合与趋势预测.在建立模型后,用实测数据与模型的预测数据相比较说明时间序列线形模型能较好地拟合与预测土壤墒情的变化趋势,可为干旱研究及其治理提供依据.     

Contributions from carbon and nitrogen in roots to closing the yield gap between conventional and organic cropping systems

This study investigates the effect of different crop rotation systems on carbon (C) and nitrogen (N) in root biomass as well as on soil organic carbon (SOC ). Soils under spring barley and spring barley/pea mixture were sampled both in organic and conventional crop rotations. The amounts of root biomass and SOC in fine (250–253 μ m), medium (425–250 μ m) and coarse (>425 μ m) soil particulate organic matter (POM ) were determined. Grain dry matter (DM ) and the amount of N in harvested grain were also quantified. Organic systems with varying use of manure and catch crops had lower spring barley grain DM yield compared to those in conventional systems, whereas barley/pea showed no differences. The largest benefits were observed for grain N yields and grain DM yields for spring barley, where grain N yield was positively correlated with root N. The inclusion of catch crops in organic rotations resulted in higher root N and SOC (g C/m²) in fine POM in soils under barley/pea. Our results suggest that manure application and inclusion of catch crops improve crop N supply and reduce the yield gap between conventional and organic rotations. The observed positive correlation between root N and grain N imply that management practices aimed at increasing grain N could also increase root N and thus enhance N supply for subsequent crops.     

不同栽培方式对温室连作黄瓜土壤微生物量碳氮和作物产量的影响

以连作8年温室连作黄瓜土壤为材料,试验设5个不同轮作方式处理, 1）早春茬黄瓜夏茬休闲秋冬茬黄瓜（CK）; 2）早春茬黄瓜夏茬休闲秋冬茬黄瓜间作大蒜（CS1）; 3）早春茬黄瓜夏茬茼蒿秋冬茬黄瓜（CS2）; 4）早春茬番茄夏茬菠菜秋冬茬黄瓜（CS3）; 5）早春茬黄瓜夏茬大蒜秋冬茬黄瓜(CS4),进行了5年的盆栽试验,采用后3年的数据,评价不同栽培方式对土壤微生物量碳氮和主栽作物产量的连年影响,探讨栽培方式对连作黄瓜土壤的修复效果。研究结果表明,相对CK,CS3在第三和四年早春茬显著增加微生物量碳、 氮以及碳/氮,CS2和CS3在三至五年夏茬显著增加微生物量碳和碳/氮, CS2显著增加三至五年早春茬、 早春茬+秋冬茬产量,CS4显著增加第3和4年早春茬、 早春茬+秋冬茬产量和第三至五年秋冬茬产量; 微生物量碳和碳/氮与秋冬茬产量呈显著正相关,与早春茬+秋冬茬产量呈极显著正相关; 处理与季节均对微生物量碳和碳/氮产生极显著影响,且两者有极显著交互作用; 季节、 处理季节对微生物量氮有显著影响,处理、 季节、 处理季节对作物产量有极显著影响。总之,CS2提高微生物量碳、 碳/氮、 作物产量效果最佳。     

Nitrogen Contribution of Peanut Residue to Cotton in a Conservation Tillage System

ABSTRACT

Leguminous crops, particularly winter annuals, have been utilized in conservation systems to partially meet nitrogen (N) requirements of succeeding summer cash crops. Previous research also highlights the benefits of utilizing summer annual legumes in rotation with non-leguminous crops. This study assessed the N contribution of peanut (Arachis hypogaea L.) residues to a subsequent cotton (Gossypium hirsitum L.) crop in a conservation system on a Dothan sandy loam (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) at Headland, AL during the 2003–2005 growing seasons. Treatments were arranged in a split plot design, with main plots of peanut residue retained or removed from the soil surface, and subplots as N application rates (0, 34, 67, and 101 kg ha^{? 1}) applied in fall and spring. Peanut residue did not influence seed cotton yields, leaf N concentrations, or plant N uptake for either growth stage or year of the experiment. There was a trend for peanut residue to increase whole plant biomass measured at the first square in two of three years. Seed cotton yields and plant parameters measured at the first square and mid-bloom responded favorably to spring N applications, but the recommended 101 kg N ha^{? 1} did not maximize yields. The results from this study indicate that peanut residue does not contribute significant amounts of N to a succeeding cotton crop, however, retaining residue on the soil surface provides other benefits to soils in the southeastern U.S.     

基于WOFOST模型分析不同气候情景对辽宁典型雨养春玉米产量的影响

气温、降水和辐射是农作物生长发育必需的基本气候要素，其大小、波动及空间分布决定局部地区的种植结构和农产品产量增减，具有喜温喜水特性的玉米其生长发育对气候变化的响应更为敏感。本研究基于辽宁省新民和朝阳地区近40a气象数据分析各气候要素变化特征，根据局地气候暖干化趋势耦合气温、降水、辐射三要素构建不同气候情景，利用田间实测数据对WOFOST模型进行校准和适用性检验，并将该模型用于模拟不同气候情景下辽宁典型雨养春玉米产量变化。结果表明：（1）验证后的WOFOST模型能较好地模拟两站点春玉米产量，其模拟值与实测值的相对均方根误差分别为8.78%和5.96%，一致性系数分别为0.82和0.96。（2）新民和朝阳两地在设定的气候要素变化范围内春玉米产量与气温呈负相关，与降水呈正相关。在气温增加，降水减少，辐射增强的不同梯度气候情景下，新民（气温+1.2℃，降水量−25%，辐射+4%）和朝阳（气温+1.4℃，降水量−25%，辐射+3%）减产幅度分别达92.5%和85.9%，接近雨养春玉米绝产的警戒气候情景。（3）新民春玉米产量受降水影响显著，朝阳则对气温变化响应敏感，而两地产量对给定比例的辐射变化均未表现出明显波动。     

春玉米产量、氮肥效率及土壤矿质氮对施氮的响应

为了提高氮肥增产效益,减少对环境的污染,通过田间试验研究了施氮量对春玉米产量、氮肥效率及土壤矿质氮的影响。结果表明,施氮量较低时,春玉米籽粒产量随施氮量增加显著增加,当施氮量高于180 kg·hm-2时,产量保持不变或有减少趋势。氮肥农学利用率、氮素吸收效率、氮素偏生产力和氮收获指数均随着施氮量增加显著降低,氮肥表观利用率和氮肥生理利用率均先增加后降低。从苗期到收获期,施氮处理0~60 cm土层硝态氮含量呈现"上升—下降—上升—下降—稳定"的变化趋势,而60~120 cm土层硝态氮在春玉米生长后期有增加的趋势。随着土层加深,土壤硝态氮含量呈波浪式下降,施氮量240 kg·hm-2和300 kg·hm-2处理在60~100 cm土层硝态氮含量均显著高于其他处理。随着施氮量增加,0~120 cm土层硝态氮累积量显著增加,当施氮量超过240kg·hm-2时,土层中累积的硝态氮存在着较大的淋溶风险。综合考虑产量、氮肥效率和环境效应,179~209 kg N·hm-2是本试验条件下春玉米的合理施氮量。     

基于气候适宜度指数预报玉米产量时旬权重系数的确定方法

利用吉林省1980-2016年春玉米作物资料、50个气象站的逐日气象资料,构建春玉米生长季各旬的气候适宜度模型。分别采用绝对值法、归一化法和相关系数法确定各旬气候适宜度权重系数,进而计算4月上旬-预报日前一旬的气候适宜度指数,分析不同方法得到的气候适宜度指数与春玉米产量气象影响指数的相关性,并进行回归分析,建立产量动态预报模型,对吉林省春玉米单产进行预报。结果表明：三种方法研究的权重系数之间存在一定差异,但总体上随生育期的变化趋势基本一致。利用1981-2012年资料回归分析建立的产量丰歉预报模型多数通过0.05水平的有效性检验,各预报模型历史拟合平均准确率均在85.0%以上,归一化均方根误差NRMSE均小于17.0%,丰歉趋势预报准确率普遍在60.0%～80.0%,三种方法差异不明显。利用模型对2013-2016年春玉米单产进行外推预报,各预报时间准确率存在波动,但绝对值法、归一化法和相关系数法所有预报时间的平均准确率分别为93.5%、90.8%、87.2%,预报结果准确率的标准差分别为32.6、69.4、116.1。且绝对值法各预报时间平均准确率均在85.0%以上。可见绝对值法预报结果的准确率和稳定性均较高,可以满足业务服务需要。     

Immediate Effects of Time and Method of Alfalfa Termination on Soil Mineral Nitrogen,Moisture, Weed Control,and Seed Yield,Quality, and Nitrogen Uptake

Three field experiments were conducted on Gray Luvisol (Typic Cryoboralf) soils in northeastern Saskatchewan to compare the effects of alfalfa (Medicago sativa Leyss) stand termination with tillage and herbicides at different times on mineral nitrogen (N) (ammonium-N and nitrate-N) and moisture content of soil in spring (experiments 1 and 2), soil moisture, volunteer alfalfa and dandelion control, plant density, seed yield, protein concentration and N uptake for wheat (Triticum aestivum L.), barley (Hordeum vulgare L), canola (Brassica rapa L.), and pea (Pisum sativum L.) crops (experiment 3). Termination treatments included combinations of times (in mid-June after cut 1, in mid-August after cut 2 and in mid-May during spring) and methods [tillage alone, herbicides alone (glyphosate + 2,4-D amine and also clopyralid + 2,4-D ester in experiment 3) and these herbicides + tillage]. Tillage alone significantly increased spring soil nitrate-N levels over herbicides alone or herbicides + tillage. Termination after cut 1 had the highest levels of soil nitrate-N. There was little effect of time and method of termination on soil ammonium-N and moisture content in spring. Herbicides + tillage generally provided better control of both volunteer alfalfa and dandelion in the four crops than tillage or herbicides alone. In general, alfalfa termination with herbicides alone significantly reduced plant density, seed yield, and N uptake of all crops and protein concentration of cereals only due to effects on levels of soil nitrate-N, dandelion control, and crop injury by clopyralid or 2,4-D residues in soil. Plant density, seed yield, N uptake and protein concentration of crops tended to decline with delay in termination time. The results of this study support the use of some tillage in alfalfa stand termination in helping to control volunteer alfalfa and dandelion and optimize annual crop yields and quality.     

Yield and N uptake as affected by soil tillage and catch crop

Two field trials with spring barley (Hordeum vulgare L.) were conducted at two locations in Denmark in order to evaluate the effects of tillage and growth of a catch crop on yield parameters under temperate coastal climate conditions. Ploughing in autumn or spring in combination with perennial ryegrass (Lolium perenne L.) as a catch crop was evaluated on a coarse sand (Orthic Haplohumod) from 1987 to 1992 at three rates of N fertiliser application (60, 90 and 120 kg N ha⁻¹ year⁻¹). Rotovating and direct drilling were also included as additional tillage practices. The experiment was conducted on a 19-year-old field trial with continuous production of spring barley. Ploughing in autumn or spring in combination with stubble cultivation and a catch crop, in addition to minimum tillage, was evaluated in a newly established field trial on a sandy loam (Typic Agrudalf) from 1988 to 1992. Yield parameters and N concentrations in grain and straw were determined. On the coarse sand, N uptake in the grain in ploughed plots without a catch crop was significantly greater when spring ploughed as opposed to autumn ploughed, but grain and straw yields did not differ significantly. Grain yield, straw yield and total N uptake did not differ significantly between direct drilled and autumn ploughed plots, but the trend was for grain yield to be lower with direct drilling. After 19 years of catch crop use, yield parameters in ploughed plots were greater than in plots without catch crops. This was most pronounced in the autumn ploughed plots. Rotovating the catch crop in the spring decreased grain yield compared with underploughing the catch crop in autumn or spring. No significant interactions were found between tillage and N rates. On the sandy loam, grain as well as straw yield and total N uptake were not significantly affected by catch crop or time of ploughing. Grain yield was significantly lower with reduced tillage (stubble cultivation in autumn) than in all other treatments.     

Cultivation of wheat following pea and triticale/pea mixtures increases yields and nitrogen content

Abstract

An experiment was conducted in 2004–2007 at the University of Podlasie Zawady Experimental Station (52°06′N, 22°50′E), Siedlce, Poland, to examine the effect of either post-harvest residues or residues and straw of spring triticale (Triticale), field pea (Pisum sativum L.) and their mixtures containing the following proportions of both components: 75+25, 50+50, 25+75% on the subsequent crop of winter wheat (Triticum aestivum L.). A field experiment was designed as split-blocks with three replicates. Residue mass, straw mass as well as N, P, K, Ca and Mg amounts were determined in the residues and straw. The residue amount of spring triticale was the greatest. N, Ca and Mg amounts in the residues of spring triticale/field pea mixtures were similar or higher whereas P and K amounts were similar or lower compared with spring triticale residues. Spring triticale straw contained less N, P, Ca and Mg than the straw of either field pea or spring triticale/field pea mixtures. Grain yield, yield components, N content and N uptake in the grain of winter wheat following field pea and spring triticale/field pea mixtures were significantly higher compared with winter wheat following spring triticale. Increasing proportions of field pea in mixtures with spring triticale cultivated as previous crops significantly increased winter wheat grain yields as well as N content and uptake. The residues of the previous crops combined with the straw significantly increased winter wheat grain yield, number of ears per m², number of grains in an ear, thousand-grain weight and N content and uptake. The highest winter wheat grain yield and N uptake were determined following an application of residues and straw of field pea and 25+75% spring triticale/field pea mixture. The grain of winter wheat after field pea had the greatest N content.     

Nitrogen conserving potential of successive ryegrass catch crops in continuous spring barley

Abstract. The nitrogen (N) conserving effects of Italian ryegrass ( Lolium multiflorum L.) undersown as a nitrate catch crop in spring barley ( Hordeum vulgare L.) were evaluated over a ten-year period in outdoor lysimeters (1.5 m deep, diam. 1 m) with sandy loam soil. Spring barley grown every year received 11.0 or 16.5 g N m⁻² before planting or was kept unfertilized. The N was given either as calcium ammonium nitrate or as ammoniacal N in pig slurry. From 1985 to 1989, ryegrass was undersown in the barley in half of the lysimeters while barley was grown alone in the remaining lysimeters. The grass sward was left uncut after barley harvest and incorporated in late winter/early spring. From 1990 to 1994 all lysimeters were in barley only.
Barley dry matter yields and crop N offtakes were not affected by the presence of undersown ryegrass, although grain yields appeared to be slightly reduced. After termination of ryegrass growing, N offtake in barley (grain+straw) was higher in lysimeters in which catch crops had been grown previously.
The loss of nitrate by leaching increased with N addition rate. Regardless of N dressing, ryegrass catch crops halved the total nitrate loss during 1985–1989, corresponding to a mean annual reduction in nitrate leaching of 2.0–3.5 g N m⁻². From 1990 to 1994, lysimeters previously undersown with ryegrass lost more nitrate than lysimeters with no history of ryegrass. The extra loss of nitrate accounted for 30% of the N retained by ryegrass catch crops during 1985–1989.
It is concluded that a substantial proportion of the N saved from leaching by ryegrass catch crops is readily mineralized and available for crop offtake as well as leaching as nitrate. To maximize benefits from ryegrass catch crops, the cropping system must be adjusted to exploit the extra N mineralization derived from the turnover of N incorporated in ryegrass biomass.