Estimating the Yield Loss of Winter Wheat from Drought in the United States Southern Plains Region as Influenced by El Niño-Southern Oscillation (ENSO)

Wheat (Triticum aestivum L.) production is a major economic activity in most regional and rural areas in the Southern Plains, a semi-arid region of the United States. This region is vulnerable to drought and is projected to experience a drier climate in the future. Since the interannual variability in climate in this region is linked to an ocean-atmospheric phenomenon, called El Niño-Southern Oscillation (ENSO), droughts in this region may be associated with ENSO. Droughts that occur during the critical growth phases of wheat can be extremely costly. However, the losses due to an impending drought can be minimized through mitigation measures if it is predicted in advance. Predicting the yield loss from an imminent drought is crucial for stakeholders. One of the reliable ways for such prediction is using a plant physiology-based agricultural drought index, such as Agricultural Reference Index for Drought (ARID). This study developed ENSO phase-specific, ARID-based models for predicting the drought-induced yield loss for winter wheat in this region by accounting for its phenological phase-specific sensitivity to drought. The reasonable values of the drought sensitivity coefficients of the yield model for each ENSO phase (El Niño, La Niña, or Neutral) indicated that the yield models reflected reasonably well the phenomena of water stress decreasing the winter wheat yields in this region during different ENSO phases. The values of various goodness-of-fit measures used, including the Nash-Sutcliffe Index (0.54 to 0.67), the Willmott Index (0.82 to 0.89), and the percentage error (20 to 26), indicated that the yield models performed fairly well at predicting the ENSO phase-specific loss of wheat yields from drought. This yield model may be useful for predicting yield loss from drought and scheduling irrigation allocation based on the phenological phase-specific sensitivity to drought as impacted by ENSO.

控失尿素对氮素利用率、土壤硝态氮含量及冬小麦增产效果的影响

为探索控失尿素的施用方法,发现控失尿素在施用中存在的问题,以冬小麦为试验对象,开展了田间小区试验,考察了不同施肥处理和施肥方式对冬小麦产量、氮素利用率和土壤硝态氮含量的影响。结果表明:施氮处理的冬小麦产量高于不施氮处理的,处理间差异极显著;氮素施用量和施肥方式相同时,控失尿素处理的冬小麦产量高于普通尿素处理的,处理间差异极显著;氮素施用量和肥料品种相同而施肥方式不同时,底施+追施的增产效果优于全底施的,处理间差异显著;控失尿素氮素施用量比普通尿素减少20%的条件下,冬小麦产量无显著性差异;与施用普通尿素的处理相比,施用控失尿素的处理不仅氮素利用率高,且均不同程度地降低了土壤中硝态氮的含量。施用控失尿素可以提高冬小麦的产量和氮素利用率,降低土壤中硝态氮的含量。

Improvement of Water Use Efficiency in Winter Wheat byBreeding Lines with Low Rate of Water Loss of Excised-Leaves

A study was conducted with the objective of improvement of water use efficiency (WUE) and yield of winter wheat for Lowland Dryland Farming systems through a breeding approach. Various genotypes were screened in 1988 for rate of water loss of excised leaves (RWL) , followed by inter-crossing of diverse parents in 1993. Analysis of the relationship between RWL and yield components and plant traits demonstrated significant differences in RWL among genotypes. Under most circumstances, RWL was correlated negatively with yield and grain weight, and positively with plant height. The results demonstrated a basis for simultaneous selection for high yield and low RWL. It was found that genotypic rank varied with the duration of water loss. Correlation between RWL and yield was reduced by extended water loss duration. Analysis of the genetic variation and segregation of RWL of progenies and the effect of simultaneous screening for RWL and agronomic traits showed that good lines with improved yield and water use performance could be obtained.

提标扩面背景下定损合理性与政府信任对农户支付意愿的影响——以安徽省小麦保险为例

近年来三大粮食作物(小麦、水稻和玉米)完全成本保险和种植收入保险从试点到全国全面实施,农业保险的提标扩面力度不断加大。该文以安徽省小麦保险为例,运用条件价值评估(Contingent Valuation Method,CVM)法,获取农户对保额分别为9750元·hm^(-2)和13500元·hm^(-2)的小麦保险的支付意愿,并运用多元线性回归模型分析定损合理性和政府信任对其支付意愿的影响。结果表明:多数农户对当前的费率水平和保费补贴比例满意,定损合理性、政府信任都显著正向影响其支付意愿;对小麦保险的认知水平越高,越愿意投保,但愿意支付的价格却更低。该文总结并提出了提高农业保险理赔精确性、优化保费补贴政策、维护政府公信力和加强农业保险的宣传等对策建议。

平原河网地区稻麦轮作农田排水与氮素流失特征研究

长江下游稻麦轮作区农田排水是区域面源污染的主要来源,明确农田排水与氮素流失特征对于区域农业生产可持续发展与生态环境保护具有重要意义。现有稻麦轮作农田排水与氮素流失研究中,一般采用农田测筒观测地表径流与深层渗漏量来估算农田氮素流失量,这与农田土壤水分与氮素主要通过侧向径流进入农田排水系统的实际情况存在偏差。本文基于4年的大田监测数据,运用田间水文水质模型DRAINMOD-NⅡ,模拟研究了不同气象条件下稻麦轮作农田排水与氮素流失规律。结果表明,稻麦轮作周年内,由排水造成的氮素流失量多年平均值为28.4 kg/hm^(2),占施肥量的6.0%,其中大部分集中在稻季,平均为25.6 kg/hm^(2),麦季氮素流失量仅为2.8 kg/hm^(2)。与现有文献报道值相比,本文模拟得出的排水总量高35.4%,氮素流失总量则低44.6%;差异主要来自麦作期,文献报道平均值(31.8 kg/hm^(2))是本文的11倍,估算方法不同可能是造成这一差异大的主要原因。结合降雨规律分析发现,农田排水量和氮素流失量与降雨变化关系显著(决定系数R^(2)>0.56),三者相对增量的变化规律几乎一致;在降雨频率为20%~80%的年份内,氮素流失量相对稳定,维持在均值的0.8~1.2倍之间;只有在重现期大于5年的干旱或湿润年份,氮素流失量才会出现较大变化。因此,通过排灌控制措施稳定农田水文过程是有效控制农田排水氮素流失的关键。

小麦机收损失的原因及减损措施

为提升小麦的收割速度,机械化收获成为最重要的收割手段。但机械化收割存在着收获损失的问题。基于此,文章探讨了小麦收割中机收损失产生的主要原因,包括小麦品种、收获时间、收获机技术状态、操作人员技术水平等。进而提出了小麦机收减损的有效措施,包括选择优良小麦品种、做好收获机的养护和调整、提高操作人员水平,建立机械化收获标准和机械设备操作规范,以保证小麦生产的高产高效。

小麦制粉系统中各粉路小麦粉加工品质的分析与评价

收集49根全粉路粉管样品,分析其理化指标;通过主成分分析和相关性分析研究小麦粉粉质对其加工的挂面烹调品质的影响。结果表明:皮磨前路(1B~2B)具有低的破损淀粉率,为4.92%~5.90%,心磨前路1M~2M具有高的峰值黏度,均大于60;挂面烹调损失率与小麦淀粉糊化时的峰值黏度呈显著负相关,与破损淀粉率呈极显著正相关。

小麦条锈病胁迫下冬小麦品种天选57号产量方程的构建

小麦条锈病一直以来都是小麦植保工作的重中之重,进一步明确小麦条锈病在甘肃陇南地区发病程度与冬小麦产量之间的相关性,为制定天水地区小麦条锈病防控指标提供科学依据。选取当地主栽冬小麦品种天选57号为研究对象,在人工接种诱发后,通过田间喷施20%三唑酮乳油135 g/hm^(2)兑水450 kg防控1~2次,并造成一定的病情梯度,实地调查田间病情并测产,得到冬小麦品种天选57号的小麦条锈病最终病情(x)与平均折合产量(y产量)间的回归方程为:y_(产量)=-8.5714x^(2)-488.57x+7512(R^(2)=0.9872)。同时通过理论折合产量计算出冬小麦品种天选57号使用20%三唑酮乳油防控1次时,产量损失率为20.13%~29.71%,挽回产量损失4.79~14.37个百分点。防控2次时产量损失率为7.35%~12.14%,挽回产量损失为22.36~27.15个百分点。得到冬小麦品种天选57号采用20%三唑酮乳油防控1次和防控2次后的植保贡献率分别为6.82%~18.00%、25.45%~29.31%。

蒲城县小麦与玉米病虫害防控植保贡献率测算试验

为科学评估蒲城县小麦、玉米生产中植物保护工作的贡献而设计试验,设置严格防治区、统防统治区、农户自防区和空白对照区,采用对角线5点取样调查的方法,在小麦返青期杂草化学除草后和灌浆期调查病虫草害发生情况,在玉米整个生育期调查病虫草害发生情况;在小麦、玉米成熟期进行理论测产和实际测产,测算不同防治水平下的亩产量、挽回损失、植保贡献率等,根据取样代表面积在全县种植面积占比计算县域植保贡献率。结果表明,植保工作可有效控制小麦、玉米病虫草害的发生,通过防治小麦、玉米病虫害发生种类和程度均明显减轻;通过计算得出蒲城县小麦生产中植保贡献率为20.56%;玉米生产中植保贡献率为23.5%。

Effects of three types of soil amendments on yield and soil nitrogen balance of maize–wheat rotation system in the Hetao Irrigation Area, China

Excessive fertilization combined with unreasonable irrigation in farmland of the Hetao Irrigation Area(HIR), China, has resulted in a large amount of nitrogen(N) losses and agricultural non-point source pollution.Application of soil amendments has become one of the important strategies for reducing N losses of farmland.However, there is still no systematic study on the effects of various soil amendments on N losses in the HIR.In this study, three types of soil amendments(biochar, bentonite and polyacrylamide) were applied in a maize–wheat rotation system in the HIR during 2015–2017.Yields of maize and wheat, soil NH3 volatilization, N2O emission and NO3– leaching were determined and soil N balance was estimated.The results showed that applications of biochar, bentonite and polyacrylamide significantly increased yields of maize by 9.2%, 14.3% and 13.3%, respectively, and wheat by 9.2%, 16.6% and 12.3%, respectively, compared with the control(fertilization alone).Applications of biochar, bentonite and polyacrylamide significantly reduced soil N leaching by 23.1%, 35.5% and 27.1%, soil NH3-N volatilization by 34.8%, 52.7% and 37.8%, and soil N surplus by 23.9%, 37.4% and 30.6%, respectively.Applications of bentonite and polyacrylamide significantly reduced N2O-N emissions from soil by 37.3% and 35.8%, respectively, compared with the control.Compared with application of biochar, applications of bentonite and polyacrylamide increased yields of maize and wheat by 5.1% and 3.5%, respectively.Our results suggest that soil amendments(bentonite and polyacrylamide) can play important roles in reducing N losses and increasing yield for the maize–wheat rotation system in the HIR, China.

NH3 Volatilization from Aboveground Plants of Winter Wheat During Late Growing Stages

Ammonia volatilized from aboveground parts of winter wheat was collected with an enclosure growth chamber and measured from jointing to maturing stage. The results showed that ammonia released from unfertilized plants grown in high and low fertility soils remained at low rates of 2.3 and 0. 9μg NH3 40 plant-1 h-1 respectively at late filling stage. However, fertilized plants rapidly increased the rates to 43. 4 and 52. 2μg NH3, 40 plant-1 h-1 in the high and low fertility soils, respectively, at the same period. The released a-mount was different in different parts of plants. At filling stage, lower senescing stems and leaves volatilized more ammonia than upper parts, i. e. , ears and flag leaves that grew normally, with an average of 1. 4 and 0.7μg NH3 20 plant-1 h-1 respectively, strongly suggesting that it was the senile organs that released large amounts of ammonia. At the grain filling stage, shortage of water supply (drought stress) reduced ammonia volatilization. The average rate of ammonia released under water stress was 0. 9μg NH3 40 plant-1 h-1, but 1.2μg NH3 40 plant-1 h-1 with moderate water supply. Application of N together with P fertilizer resulted in a higher ammonia volatilization than N fertilization alone at the maturing stage. The average rate released was 135.3 μg NH3 40 plant-1 h-1 when 0.4 g N and 0.13 g P had been added to per kg soil, while 33. 7μg when 0. 4 g N added alone. Ammonia volatilization from plants was closely related with plant biomass and N uptake;P fertilization increased plant biomass and N uptake and therefore increased its release.

Effects of Powdery Mildew on 1 000-Kernel Weight, Crude Protein Content and Yield of Winter Wheat in Three Consecutive Growing Seasons

In order to clarify the impact posed by wheat powdery mildew （Blumeria graminis f. sp. tritici） on the yield and yield components in different epidemic seasons, field trials were conducted in three growing seasons, 2009-2010, 2010-2011 and 2011-2012, in Langfang City, Hebei Province, China. The relationships between 1000-kernel weight, crude protein content of grain and yield and disease index （DI）, as well as area under disease progress curve （AUDPC） were studied. The models of the percentage of loss of 1000-kernel weight, crude protein content and yield were constructed using DI at critical point （CP） of growth stages （GS） and AUDPC in the three growing seasons, respectively. The CPs for estimating 1 000-kernel weight, crude protein content of grain and yield of wheat caused by powdery mildew were GS 11.1, GS 10.5.3 and GS l 0.5.3, respectively. Models based on DI at CP to estimate the percentage of loss of 1000-kernel weight, crude protein content of grain and yield were better than models based on AUDPC. And models of the percentage of loss of 1000-kernel weight, crude protein content and yield for 2011-2012 season were significant different from these for 2009-2010 and 2010-2011 seasons. These results indicated that besides powdery mildew, weather conditions also had influence on 1 000-kernel weight, crude protein content of grain and yield loss of wheat when powdery mildew occurred.

不同小麦品种籽粒灌浆、脱水特性及其与产量和品质的关系

【目的】鉴选具有灌浆脱水快、丰产性好且籽粒品质优的小麦品种,避免迟播条件下小麦遭遇高温逼熟的危害。【方法】以全国5个生态区的11份小麦品种为材料,分析其灌浆脱水特性、籽粒产量和品质表现。【结果】最大灌浆速率和灌浆持续时间均与生理成熟期籽粒质量呈显著正相关关系,并能最终反应收获期籽粒产量。所有参试品种中济麦22产量最高,达6 195 kg·hm^(-2),其次云麦53为5 898 kg·hm^(-2);郑麦7698和绵麦367产量分别居第3和第4。济麦22灌浆脱水快,且灌浆高峰持续时间长,其籽粒品质符合长江中下游地区中、弱筋型小麦的选育需求,绵麦367的籽粒品质达优质弱筋标准。研究还发现,籽粒脱水阶段表现出籽粒质量不稳,其原因可能是存在小麦籽粒回浆所致。【结论】协调最大灌浆速率和灌浆持续时间有利于提高籽粒产量和脱水速率;生产上可通过调优栽培措施改善和提高中筋、弱筋型小麦品种籽粒品质,并结合籽粒品质检测和鉴选提高品质育种准确性。

冬小麦倒伏灾害损失实验研究与应用——以河北省定兴县为例

倒伏是河北省冬小麦常见的自然灾害之一,几乎每年都会造成大量减产。选取河北定兴县冬小麦种植区,采用倒伏模拟实验评估了生育期不同生长阶段冬小麦产量损失率。结果表明,灌浆初期冬小麦倒伏损失率最高,达到45.02%;灌浆半粒期次之,为28.70%;乳熟期、蜡熟期、成熟期损失依次降低;成熟期损失最小,为2.87%;灌浆期也是冬小麦需水旺盛期,因此规划好灌浆期灌溉,降低倒伏概率十分必要。该研究为冬小麦倒伏保险产品开发及区域防灾减灾规划提供借鉴,同时也可为小麦倒伏灾害快速定损理赔提供依据。

基于EDEM小麦收获机清选损失监测试验装置设计

针对小麦损失监测传感器结构复杂、成本较高的问题,对收获机清选排杂口不同物料运动特性进行研究,揭示小麦与秸秆撞击敏感板的作用规律,从清选抛出物冲击敏感板的力学特性出发,设计一种小麦收获机清选损失监测试验装置。通过离散元分析软件EDEM分析小麦籽粒、50 mm秸秆、100 mm秸秆撞击敏感板产生的作用力,分析接触力变化曲线,证明可通过判断物料撞击敏感板产生的信号进行损失监测。为增强信号采集准确率,采用两片压电传感器串联的方式,增大损失信号。设计损失监测试验台机械结构及控制系统,使监测装置模拟收获机清选排杂过程且可以实时监测信号,有效提高监测效率。最后,通过不同高度物料运动损失监测试验,得出300 mm高度下传感器识别较为精准,对小麦籽粒的识别率达到98.4%,整体监测误差小于5%,损失监测试验装置能够达到设计目的和要求。

2015—2020年臭氧对中国主要粮食作物产量及其经济效益的影响

基于2015—2020年中国国控监测站点的臭氧观测数据,结合高时空分辨率的农田、农作物以及生长发育旬值数据,利用累积暴露阀值超过40 nmol/mol的暴露响应关系(Accumulate Exposure Over a Threshold of 40 nmol/mol,AOT40),评估臭氧污染导致3种主要农作物产量的损失。结果显示:在2015—2020年,春小麦、冬小麦、早稻、一季稻、晚稻、春玉米、套种玉米、夏玉米与剩余玉米的AOT40年均摩尔比分别为8.4~11.5μmol/mol、6.7~11.5μmol/mol、4.4~8.4μmol/mol、6.8~8.3μmol/mol、5.6~10.1μmol/mol、6.1~8.5μmol/mol、7.8~10.4μmol/mol、7.8~10.4μmol/mol和10.1~12.7μmol/mol。水稻、小麦和玉米AOT40较高区域主要集中在北京、河北、天津、山东、河南和山西等地,以及安徽、江苏等长三角地区,同时上述地区也为臭氧污染风险地区。2015—2020年中国春小麦、冬小麦、早稻、一季稻、晚稻、春玉米、套种玉米、夏玉米以及剩余玉米的相对产量损失分别为16.3%~26.1%、19.6%~33.7%、3.8%~6.6%、6.2%~7.6%、5.5%~10.5%、3.1%~4.3%、5.4%~7.0%、4.9%~6.7%和6.2%~8.0%。2015—2020年因臭氧污染引起的水稻、小麦和玉米产量损失分别为9917.5万t、30282.5万t和7700.6万t,经济损失分别为4.6×10^(10)美元、1.1×10^(11)美元和3.0×10^(10)美元。水稻、小麦和玉米等作物因臭氧污染所导致产量损失较大的区域主要为该作物主产区。本文量化了2015—2020年由于臭氧暴露导致的水稻、小麦和玉米产量及经济损失,结果可为全国臭氧污染管控与农业生产管理提供科学支撑。

中国粮食减损的小农参与:回顾、反思与展望——以河南省A县捡麦人为例

中国粮食安全目标实现有赖于粮食系统的转型,涉及对传统农业生产方式和传统小农行为方式的再认识。聚焦中国小麦收获环节传统劳作方式的变迁过程,通过对河南省A县19个村庄捡麦人的实证考察,揭示了农村捡麦人的历史演变及社会价值。研究发现:(1)受农业土地制度、机械收割技术、理性经济人逻辑及农户个体差异的影响,农户参与粮食减损行为从新中国成立至今呈整体性消退的趋势;(2)通过倡导和重振小农参与的粮食减损行为,对缓解国家粮食安全问题、延续粮食节约优秀传统文化、激发农村剩余劳动力活力具有重要价值;(3)国家推动粮食减损,离不开农村各利益相关者的参与,需要构建以政府为主导、以小农参与为核心的多主体协同减损机制。

基于卷积神经网络的田间麦穗检测方法研究

为提高卷积神经网络对麦穗的识别检测精度,在YOLOv5检测模型基础上提出改进的识别检测模型YOLOv5-αTB,在特征提取网络末端部分加入Transformer模块,强化特征提取网络对小麦麦穗图像的颜色、纹理、几何等特征的提取,在特征融合部分将路径聚合网络(path aggregation network,PANet)替换成加权双向特征金字塔(bidirectional feature pyramid network,BiFPN),进一步优化多尺度特征的融合。针对边界框回归损失函数的计算方式IoU的局限性,引入了α-CIoU加强了边界框回归的效果。利用YOLOv5-αTB检测模型在测试集上得到的精确度(precision)、召回率(recall)和平均精度(average precision,AP)分别是99.95%、81.86%和88.64%,在平均精度上相比于传统的YOLOv5模型提升2.92个百分点。该模型检测统计麦穗数量对比人工计数结果,识别检测精度约为97.00%。

稻麦轮作农田有机无机肥配施下磷平衡研究

为探究太湖流域稻麦轮作农田有机无机肥不同配施方式下的磷平衡,通过控氮控磷(4 a)和控氮不控磷(24 a)两种配施方式的田间定位试验,分析稻麦产量及磷吸收量、土壤磷含量、径流磷损失以及磷平衡。控氮控磷试验设有6个处理:不施磷肥(CK),单施化肥(CF),有机无机肥配施中包括商品肥OM、猪粪PM、鸡粪CM及牛粪DM(均为有机肥等氮磷钾替代30%化学磷肥);控氮不控磷试验设有3个处理:不施磷肥(CK)、单施化肥(CF)、猪粪有机无机肥配施(PM),配施方式为有机肥仅等氮替代稻季40%和麦季50%化学氮肥。结果表明:相较CF处理,控氮控磷配施方式各处理稻麦周年磷素略有盈余,径流磷损失量无显著性差异,CF、OM、PM、CM、DM磷平衡(以P计)分别为-0.76、2.29、4.58、4.40、8.54 kg·hm^(-2),径流磷损失量为0.08~0.15 kg·hm^(-2);控氮不控磷配施方式PM稻麦周年磷平衡及径流磷损失量显著提高3.41倍和50.4倍,CF和PM磷盈余量分别为26.7、118 kg·hm^(-2),径流磷损失量分别为0.10、5.14 kg·hm^(-2)。相较控氮控磷,控氮不控磷配施的磷盈余及径流磷损失量均大幅增加。综上表明,有机无机肥总投入量过高会导致土壤磷大量盈余,极大增加磷损失的环境风险。因此,施用有机肥的同时应考虑控制氮磷施入量,有机肥部分替代化肥养分等量控制是可行的有机无机肥配施方式。

不同施肥模式对巢湖流域麦田氮磷流失及小麦产量的影响

为了减轻巢湖流域农业氮磷流失对巢湖的污染,以巢湖流域稻麦轮作的麦季为研究时段,通过田间小区实验,研究不同施肥模式对麦田径流中氮磷流失、小麦产量及肥料利用率的影响。结果表明:施肥能显著增加麦田径流中氮磷流失浓度(p<0.05);与常规施肥(CG)相比,测土配方施肥(CT)、化肥减施+有机肥(YH1)、化肥减施+生物炭(YH2)、控释肥(KS)4种施肥模式总氮减排33.35%~38.73%,总磷减排22.95%~34.43%。与不施肥(CK)相比,施肥后小麦产量显著提高(p<0.05),不同施肥模式下小麦产量差异不显著(p≥0.05),但经济效益存在差异性。与CG相比,CT、YH1、YH2、KS可以提高氮肥和磷肥利用率,氮肥利用率提高了6.89%~14.47%,磷肥利用率提高了16.39%~31.71%。KS施肥模式在麦田氮磷减排和经济效益方面具有优势。