Comparative Advantage Analysis of the Main Grain Crops in Henan Province

Based on the summarization of the status quo of the research both at home and abroad,the changing trend of the production of the main grain crops,covering the planting structure,seed structure and the trend of the per unit yields of garlic are analyzed.According to the comparative advantage theory,the comprehensive comparative advantages indices,which have been revised,can be used as the main research methods.By using the relevant data from 2000 to 2006,the scale comparative advantage,the efficient comparative advantage and the comprehensive comparative advantages of the main grain crops(wheat,millet,corn,soybean,rice and tuber crops)in each city of Henan Province are measured.The results show that among the main grain crops in Henan Province,only the wheat and the corn have comparative advantages;rice,corn,soybean and tuber crops all do not have the scale advantages;the wheat,millet and the potatoes have obvious efficiency advantages while rice,corn and soybean have relatively weak efficiency advantages;wheat and corn have comprehensive comparative advantages,while rich,millet,soy bean and potatoes do not have the comprehensive comparative advantages.Combining with the current specific situation of Henan Province,the general situation faced by the production of main grain crops in Henan Province is analyzed specifically.In the end,suggestions on adjusting the structure of the main grain crops are put forward.

An Intelligence Decision Support System for Diagnosis and Management of Grain and Cotton Crop Pests in Xinjiang

Xinjiang Uygur Autonomous Region is a scarcely populated area in China and technicians for plant protection are extremely deficient.The occurrence areas of insect pests in grain and cotton crops have been increasing year by year, causing serious economic losses. Aiming for several main grain and economic crops of Xinjiang(cotton, corn and wheat), an intelligence decision support system for diagnosis and management of grain and cotton crop pests in Xinjiang was designed and developed, which was based on android platform and windows system architecture. APP application program of smart phones was used as an implementation form. The intelligence decision support system will help plant protection personnel and farmers to solve local pest recognition and prevention control problem at the grassroots level in Xinjiang remote regions.

Study on the Effect of "Crayfish-Rice Continuous Cropping" on Grain Production:A Case Study of Hubei Province

Taking Hubei Province as an example,starting with the present situation and existing problems of grain production,this paper expounds the great significance of"crayfish-rice continuous cropping"model in improving grain quality,and analyzes the beneficial influence of"crayfish-rice continuous cropping"on grain production and the difficulties it faces.This paper also puts forward some measures and suggestions for the further popularization of"crayfish-rice continuous cropping"in order to maintain food security.

Non-leguminous winter cover crop and nitrogen rate in relation to double rice grain yield and nitrogen uptake in Dongting Lake Plain, Hunan Province, China

Annual ryegrass（Lolium multiflorum Lam.）, a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year（2009–2011） field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass（RG） as a winter cover crop and winter fallow（WF） without weed. Subplots were three N treatments for each rice season： 0（N_0）, 100（N_（100）） and 200 kg N ha–1（N_（200））. In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice（0.4–1.7 t ha–1 for grain yield and 4.6–20.3 kg ha–1 for N uptake） and double rice（0.6–2.0 t ha–1 for grain yield and 6.3–27.0 kg ha–1 for N uptake） when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N_（100） and N_（200） plots than in N_0 plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.

Influence of Crop Nutrition on Grain Yield,Seed Quality and Water Productivity under Two Rice Cultivation Systems

The system of rice intensification （SRI） is reported to have advantages like lower seed requirement,less pest attack,shorter crop duration,higher water use efficiency and the ability to withstand higher degree of moisture stress than traditional method of rice cultivation.With this background,SRI was compared with traditional transplanting technique at Indian Agricultural Research Institute,New Delhi,India during two wet seasons （2009-2011）.In the experiment laid out in a factorial randomized block design,two methods of rice cultivation [conventional transplanting （CT） and SRI] and two rice varieties （Pusa Basmati 1 and Pusa 44） were used under seven crop nutrition treatments,viz.T 1,120 kg/hm2 N,26.2 kg/hm2 P and 33 kg/hm2 K;T 2,20 t/hm2 farmyard manure （FYM）;T 3,10 t/hm2 FYM＋ 60 kg/hm2 N;T 4,5 t/hm2 FYM＋ 90 kg/hm2 N;T 5,5 t/hm2 FYM＋ 60 kg/hm2 N＋ 1.5 kg/hm2 blue green algae （BGA）;T 6,5 t/hm2 FYM＋ 60 kg/hm2 N＋ 1.0 t/hm2 Azolla,and T 7,N 0 P 0 K 0 （control,no NPK application） to study the effect on seed quality,yield and water use.In SRI,soil was kept at saturated moisture condition throughout vegetative phase and thin layer of water （2-3 cm） was maintained during the reproductive phase of rice,however,in CT,standing water was maintained in crop growing season.Results revealed that CT and SRI gave statistically at par grain yield but straw yield was significantly higher in CT as compared to SRI.Seed quality was superior in SRI as compared to CT.Integrated nutrient management （INM） resulted in higher plant height with longer leaves than chemical fertilizer alone in both the rice varieties.Grain yield attributes such as number of effective tillers per hill,panicle length and panicle weight of rice in both the varieties were significantly higher in INM as compared to chemical fertilizer alone.Grain yields of both the varieties were the highest in INM followed by the recommended doses of chemical fertilizer.The grain yield and its attributes of Pusa 44 were significantly higher than those of Pusa Basmati 1.The seed quality parameters like germination rate and vigor index as well as N uptake and soil organic carbon content were higher in INM than those in chemical fertilizer alone.CT rice used higher amount of water than SRI,with water saving of 37.6% to 34.5% in SRI.Significantly higher water productivity was recorded in SRI as compared to CT rice.

高标准农田建设提升了农户种粮积极性吗?——基于双季稻种植的考察

高标准农田建设是增强粮食综合生产能力,强化国家粮食安全保障的重要举措。基于江西省1556份微观农户调查数据,采用双季稻种植行为来衡量农户种粮积极性,实证分析高标准农田建设对传统双季稻主产区农户种粮积极性的影响及其作用机制。研究发现:(1)高标准农田建设显著提高了农户种粮积极性,促进传统双季稻主产区农户种植双季稻,并扩大双季稻种植规模,该结论在进行稳健性检验后依然成立。(2)机制分析表明,促进农业社会化服务发展、降低农业生产成本、诱导农地转入是高标准农田建设提高农户种粮积极性的三个重要路径。(3)异质性分析发现,高标准农田建设对农地调整、低细碎化与非平原地区农户的双季稻种植行为有更明显的促进作用。为进一步强化粮食安全保障,更好地发挥高标准农田建设的种粮激励效应,应持续大力推进高标准农田建设,优化高标准农田建设模式,着力降低高标准农田的细碎化程度。

气候变化对中国东北三省主要粮食作物影响研究综述

全球气候变化已经成为事实,并且导致全球粮食危机和饥饿风险增加。东北三省作为我国主要的粮食生产基地,对气候变化十分敏感。本文梳理了当前及未来气候变化对东北三省玉米、水稻和大豆生产影响的相关研究,概括了当前主要研究方法、东北三省主要作物对气候变化的响应以及应对措施,并进一步评述了当前主要研究方法和研究领域的不足:1)研究气候变化和极端气候事件对作物生长发育和产量影响的主要方法包括田间试验法、统计分析法以及作物模型法,其中田间试验法结果最直观,统计分析法可操作强、应用范围最广,作物模型法机理性强。2)东北三省气候变化明显,并且随着气候变化,干旱逐渐取代低温冷害成为当地主要灾害。3)气候变化对东北三省作物生产整体是有利的。气候变暖改善了东北三省热量资源,不仅使作物种植区域逐渐北移,作物品种也逐渐从早中熟向中晚熟转变。4)随着气候变暖不断加剧,未来东北地区作物应选择耐高温、抗旱和抗寒等抗逆性强的品种;加强农田水利设施建设,增强应对干旱洪涝灾害的能力;采用新的农业管理措施,保护土壤健康以及粮食生产安全。5)未来需要加强对CO_(2)补偿效应以及病虫害等的研究,加强对作物模型的完善,以更好地应对气候变化对粮食安全的不利影响。

施用有机肥和秸秆还田对旱地玉-麦二熟体系作物产量、品质和化肥效率的影响

为探明施用商品有机肥和秸秆还田对旱地夏玉米-冬小麦二熟体系作物产量、品质和肥料利用效率的影响,于2015—2020年度设置不施肥+秸秆不还田(CK)、施氮磷肥+秸秆不还田(NP)、施氮磷肥+秸秆不还田+商品有机肥(NPO)和施氮磷肥+秸秆还田(NPS)4个处理进行田间试验,测定并分析作物产量、氮磷肥农学效率、籽粒养分含量、蛋白质含量以及冬小麦籽粒中蛋白质组分含量。结果表明:(1)与NP和NPO处理相比,NPS处理夏玉米5 a平均产量分别显著提高21.33%和20.77%,周年产量分别显著提高9.99%和13.43%,但3个施肥处理间小麦产量差异不显著。(2)施用商品有机肥和秸秆还田对夏玉米、冬小麦的籽粒品质均有显著影响。与NP处理相比,NPO处理冬小麦籽粒各蛋白质组分含量提高5.69%~8.28%;NPS处理冬小麦籽粒氮含量、钾含量和各蛋白质组分含量分别提高4.68%、3.96%和7.75%~11.38%。相较于NPO处理,NPS处理冬小麦籽粒钾含量、谷蛋白含量、贮藏蛋白含量和谷醇比分别显著提高14.41%、9.86%、5.39%和9.65%,夏玉米籽粒蛋白质含量、产量和籽粒氮、籽粒磷含量以及周年蛋白质产量分别显著提高6.45%、28.89%、6.40%、23.08%和10.43%。(3)相较于NP和NPO处理,NPS处理夏玉米氮肥的农学效率分别提高118.35%和113.25%,周年氮、磷肥农学效率分别提高42.83%和64.36%、42.86%和64.27%,但3个施肥处理间冬小麦氮肥、磷肥农学效率5 a均值无显著差异。综合来看,长期施用商品有机肥和秸秆还田可改善冬小麦籽粒中的蛋白质组分特性,秸秆还田还能增加夏玉米籽粒钾含量和冬小麦籽粒蛋白质含量和蛋白质产量,秸秆还田较施用商品有机肥更利于提高旱地玉-麦二熟区作物产量、品质和肥料利用效率。综上所述,施氮磷肥+秸秆还田的管理模式更适宜在旱地玉-麦二熟区进行推广。

氮肥减量后移改善植株光合特性提高麦-玉周年产量及经济效益

【目的】针对黄淮海平原传统施氮技术下,小麦-玉米两熟体系作物生育后期土壤氮肥供应不足导致籽粒减产等问题,探讨氮肥减量后移对植株光合特性、干物质积累及周年籽粒产量和经济效益的影响,为进一步优化施氮制度提供理论依据。【方法】2020—2023年,于山东济阳典型麦-玉两熟种植区,设置周年施氮400 kg·hm^(-2)传统农户处理(CK,小麦季200 kg·hm^(-2):65%基肥+35%返青肥,玉米季200 kg·hm^(-2):100%基肥)、周年减氮10%(SN,小麦季180 kg·hm^(-2):50%基肥+50%返青肥,玉米季180 kg·hm^(-2):100%基肥)、周年减氮20%(NH,小麦季180 kg·hm^(-2):22.2%基肥+33.3%返青肥+44.5%抽穗肥,玉米季140 kg·hm^(-2):28.6%基肥+71.4%大喇叭口肥)和周年减氮30%(NL,小麦季140 kg·hm^(-2):43%返青肥+57%抽穗肥,玉米季140 kg·hm^(-2):100%大喇叭口肥)4种施氮制度,研究不同施氮制度下麦-玉两熟体系的光合特性、籽粒产量和经济效益。【结果】氮肥后移优化了氮肥减量条件下作物光合特性,其中,叶面积指数3年均值,小麦拔节和开花期NL较CK、SN和NH处理分别显著提高19.0%—40.1%和21.6%—36.7%,夏玉米吐丝期NL较CK和SN处理显著提高6.8%—7.3%;叶片SPAD值3年均值,冬小麦拔节和开花期NL较CK、SN处理分别显著提高7.7%—10.0%和7.4%—12.9%,灌浆中期NL较CK、SN和NH处理显著提高5.2%—16.2%;夏玉米大喇叭口期NL和NH较CK、SN处理3年均值分别显著提高9.0%—9.4%和6.7%—7.1%,吐丝和灌浆中期NL较CK、SN和NH分别显著提高5.1%—9.4%和4.1%—9.2%;净光合速率3年均值,小麦拔节、开花和灌浆中期NL较CK、SN处理分别提高8.9%—13.3%、14.0%—18.1%和20.1%—24.4%;夏玉米大喇叭口、吐丝和灌浆中期NL较CK、SN处理分别提高4.2%—5.7%、8.7%—13.4%和7.7%—12.8%。NL处理通过增加氮肥后移量,改善了各生育阶段地上部干物质积累强度,稳定或提高了各生育时期地上部干物质积累量,冬小麦拔节、开花和成熟期地上部干物质积累量的3年均值较CK分别显著提高26.7%、27.4%和18.1%,夏玉米吐丝期显著提高14.4%。氮肥后移通过改善氮肥减量条件下光合特性,促进了各生育时期地上部干物质积累,最终实现冬小麦、夏玉米及周年籽粒产量的3年均值,NL较CK处理分别显著提高20.5%、18.1%和19.1%,经济效益分别显著提高32.4%、23.8%和27.9%。【结论】黄淮海平原麦-玉两熟体系,周年减氮30%制度下通过增加氮肥后移量,改善了作物光合特性(叶面积指数、叶片SPAD值和净光合速率),优化了各生育阶段地上部干物质积累强度和干物质积累量,从而促进冬小麦、夏玉米及周年总产和经济效益的提高。

Carbon and Nitrogen Footprints of Major Cereal Crop Production in China:A Study Based on Farm Management Surveys

Greenhouse gas(GHG)emissions and reactive nitrogen(Nr)releases are central environmental problems,which are closely linked to climate change,environmental ecology and crop production.Sustainable development of agriculture plays an important role in GHG emissions and Nr loss.The life cycle assessment(LCA)method was used to calculate the product and farm carbon footprints(CFs)and nitrogen footprints(NFs)in rice,wheat and maize production in China based on farm survey data.The results pinpointed that the CFs of rice,wheat and maize were 0.87,0.30 and 0.24 kg/kg.Meanwhile,the computed NFs were 17.11,14.26 and 6.83 g/kg,respectively.Synthetic nitrogen fertilizer applications and methane(CH4)emissions were dominant CF sources,while ammonia(NH3)volatilization was the main NF contributor.Moreover,significant decreases in CF and NF by 20%–54%and 33%–61%,respectively,were found in large-size farms(>20 hm^(2))when compared to small-size farms(<0.7 hm^(2)).Furthermore,the significantly positive relationships between CF and NF indicated the potential for simultaneous mitigation in the regions with high agricultural inputs,like amounts of fertilizer.Based on our results,some effective solutions would be favorable toward mitigating climate change and eutrophication of the major cereal crop production in China,especially optimizing fertilizer use and farm machinery operation efficiencies,as well as developing large-size farms with intensive farming.

“数智”化推动贵州现代山地特色高效农业发展以谷类作物为例

面对地形复杂和土地资源有限、气候条件不稳定、农业基础设施薄弱、农业人口技术水平较低等不利条件,贵州省积极投入,着力推动“数智”化建设,以实现“十四五”现代山地特色高效农业发展目标。以谷类作物为例,本文论述了贵州山地特色农业发展中面临的挑战以及采取的“数智”化举措,以期为进一步推动山地农业现代化提供参考。

青贮玉米与籽粒玉米间作生产性能和营养品质综合评价

试验旨在确定不同基因型玉米间作后的生产性能。采用青贮玉米和籽粒玉米间作,研究不同间作模式对群体鲜草产量、穗产量、干物质含量以及饲用品质的影响。结果显示,与单作相比,H14处理(龙牧7号与裕丰303以2∶2间作)的穗产量、鲜草产量和干物质含量均高于其他组合处理。H20处理(单播北农青贮208)粗蛋白含量最高,为15.71%,其次是H14(龙牧7号与裕丰303以2∶2间作)处理,粗蛋白含量为15.38%。H4处理(龙牧7号与裕丰303以3∶1间作)粗脂肪含量最高,为2.80%,显著高于其他各组合处理(P<0.05)。H22处理(单播籽粒玉米裕丰303)淀粉含量最高为36.69%,其次是H21(单播籽粒玉米先玉335)处理和H2(北农青贮208与裕丰303以1∶3间作)处理,淀粉含量分别为35.11%和35.10%。H20(单播北农青贮208)的相对饲喂价值为160.44,其次是H18(京科青贮932与裕丰303以2∶2间作)相对饲用价值为159.56。研究表明,通过隶属函数综合评价结果显示,与单作相比,龙牧7号青贮玉米与裕丰303籽粒玉米以2∶2间作其隶属函数值最大,生产性能最高,其次是京科青贮932与裕丰303以2∶2间作,隶属函数值位居第二,而北农青贮208与裕丰303以1∶3间作隶属函数值排名第三。

基于辐射改进Penman-Monteith模型估算粮食主产区参考作物蒸散量

为进一步提高Penman-Monteith模型估算参考作物蒸散量(Reference crop evapotranspiration,ET0)的精度,以中国粮食主产区为研究对象,将其划分为温带湿润半湿润地区(THSZ)、温带干旱半干旱地区(TASZ)、暖温带半湿润地区(WTSZ)和亚热带湿润地区(SHZ),基于32个气象站点1994-2020年长序列实测逐日气象数据,将猎豹算法(CO)、沙猫算法(SCSO)、野狗算法(DOA)优化的时间卷积神经网络模型(TCN)和3种基于日照时数、3种基于温度的经验模型估算的辐射(R_(s))值与PM模型进行融合,得到改进PM模型。以均方根误差(RMSE)、决定系数(R^(2))、平均绝对误差(MAE)和效率系数(E_(NS))为精度评价体系,找出了粮食主产区不同分区的ET0最优估算模型,结果表明:基于日照时数模型的计算精度要优于温度模型,其中CO-TCN模型在全区内均表现出了较高的精度,在不同分区的RMSE、MAE、R^(2)和E_(NS)中位数取值分别为0.099~0.171 mm/d、0.057~0.111mm/d、0.984~0.998、0.983~0.997,由此可将CO-TCN模型估算的辐射值与PM模型融合,作为标准值用于估算粮食主产区ET0。

豆科作物轮作强化农田生态系统功能的研究进展

集约化农业对保障国家粮食安全至关重要,但其导致的生态环境代价与绿色可持续发展之间的矛盾日益突出。引入豆科作物到农田生态系统对于实现地力保育、作物丰产稳产和资源优化利用等多目标协同具有重要意义。本文系统总结了豆科作物轮作对作物生产和土壤功能的主要影响:1)豆科作物通过生物固氮、高质量的根际分泌物输入、秸秆还田等过程改善了土壤氮素水平,产生正向的残留效应,有利于后茬作物增产,且增产效应在低产区更显著;2)豆科作物轮作可以通过氮肥减施降低系统N_(2)O排放,但豆科的生物固氮过程有增加CO_(2)排放的风险;3)低C/N、高氮含量的豆科秸秆还田能够提高土壤微生物活性和残体积累,提高土壤固碳效率,但其固碳效应也受到较低的秸秆生物量投入限制;4)豆科作物可以提高后茬作物的水肥利用效率,同时利用前后茬作物根系深浅合理搭配,实现轮作周年水肥高效利用。因此,将豆科作物引入到轮作系统可实现氮肥减施和增产,但其产生的土壤固碳和温室气体减排效应受到作物种类、肥料投入、土壤和气候条件等多种因素的综合影响。为更好地发挥豆科作物轮作优势,应深入探究豆科促进后茬作物增产和驱动地下部生态功能提升的耦合机制,开发豆科作物轮作配套田间管理技术,并定向设计适合我国典型生态区的新型生态高效种植体系,对推动豆科作物轮作模式构建与应用及农业绿色发展具有重要理论意义和实践价值。

种植结构“趋粮化”:劳动力外流的影响及其异质性

已有关于农业种植结构“趋粮化”研究忽视粮食作物的品种结构差异和区域差异,存在以户为单位度量劳动力外流的选择差错及要素替代发生主体不一致带来的行为逻辑分析偏误。基于全国农村固定观察点2004—2018年村级面板数据,实证分析劳动力外流对农业种植结构“趋粮化”的影响及其异质性。结果表明:相悖于现有文献的主流观点,整体上农村劳动力外流对粮食种植比例的影响不显著,水稻主产区农村劳动力外流甚至会显著抑制种植结构“趋粮化”,这一结论经过多重稳健性检验依然成立。原因在于,劳动力外流显著促进了土地流转和规模经营,强化了水稻种植“双改单”和复种指数下降的趋势。

小杂粮深加工与营养价值提升的可持续发展策略研究

通过分析小杂粮深加工产业现状,提出了推广绿色种植技术、加大科技研发投入、政府提供财政和税收支持等小杂粮产业的可持续发展策略,旨在减少环境污染、提高小杂粮产量和品质、降低生产成本和经营风险,从而推动小杂粮产业的创新升级和可持续发展。

Grain Hermetic Storage Adoption in Northern Uganda: Awareness, Use, and the Constraints to Technology Adoption

Post-harvest storage losses (PHLs) remain significant in Sub-Saharan Africa (SSA) due to several factors mainly insect pests and molds. Hermetic storage technologies (HSTs) are being promoted to address these storage losses. In Uganda, HSTs were first introduced in 2012. However, its use among farming households remains low today. Data were collected from 306 smallholder farmers from four districts of Northern Uganda using a pre-tested semi-structured questionnaire to understand their knowledge, use, and constraints to the adoption of hermetic storage. A multivariate Logit regression model was used to find the significance of the factors affecting adoption. Results showed low awareness and use of hermetic storage among smallholder farmers. Only 53.3% of the interviewed farmers were aware of the use of hermetic storage for grain storage. The SuperGrain bag was the most known form of hermetic storage (35.3%), followed by the Purdue Improved Crop Storage (PICS) bag (34.9%), metallic silo (15.5%), and plastic silo (14.4%). Hermetic storage use was even lower as only 17.6% of the surveyed farmers were using one or more forms of hermetic storage to store their grains. Insect pest management without chemical insecticides was the main reason (83.1%) for hermetic storage use. About 75.5% of those aware of hermetic storage had received training in the technology. Hermetic storage use in farming households led to improved food availability, household income, and nutrition. Lack of local availability (50.2%), high costs (37.8%), and inadequate knowledge (6.9%) were the main constraints hindering the adoption of hermetic storage in Northern Uganda. The logit regression models showed that only training in hermetic storage significantly (p = 0.002) affected farmers’ decision to adopt hermetic storage. Understanding the factors that constrain the adoption of HSTs could provide policymakers with important information to initiate and design policies and programs aimed at reducing crop storage losses.

关于我国小杂粮产业发展优势的问题及对策思考

小杂粮的市场前景广阔。通过分析我国小杂粮的种植历史现状、地区分布、主要品种及其使用价值,总结出我国小杂粮产业发展的优势及存在问题,提出了对策并分析可持续发展的可行性,以期对促进我国小杂粮产业健康发展起到指导作用。

“关中—天水经济区”粮食作物水分生产力时空演变及其驱动力分析

基于2001~2020年粮食产量数据和土地覆盖、植被指数、地表温度、蒸散量等多种MODIS产品,通过对粮食产量空间化与MODIS数据重构,从而估算得到作物水分生产力,辅以趋势分析、Hurst指数分析、地理探测等方法,探讨了关—天经济区作物水分生产力时空变化特征、未来变化趋势以及其驱动力。结果如下:(1)2001~2020年关—天经济区粮食作物水分生产力呈现出明显的降低趋势,降低趋势为-0.59×10^(-2)kg/m^(3)/a,作物生长水分利用效率不断降低。(2)从粮食作物水分生产力未来变化特征可知,粮食作物水分生产力持续减小区面积比例达49.07%,主要分布于咸阳南部以东的中东部地区,集中于渭南大部分耕作区。关—天经济区中东部的粮食作物水分生产力将面临严峻考验,而经济区中西部区域粮食作物水分生产力将表现出较大的提升空间。(3)地表参数类因子对于粮食作物水分生产力分布的影响程度最高,其次为气象因子和地形因子,三类因子对粮食作物水分生产力分布的影响程度随时间变化均呈增加趋势,且地表参数影响程度增加趋势最为显著。因此,有效减少粮食作物蒸散量和地表温度,从而增加土壤贮水量是提高粮食作物水分生产力的直接途径,如施行秸秆还田、有机培肥、合理灌溉等措施。(4)从灌溉时间来看,第33~81天、第113~161天以及第193~209天q统计值均大于q均值,三个时段适当进行灌溉对提高粮食产量具有重要作用,其中在第65天(3月上旬)和第193天(7月中旬)土壤水分的变化对作物水分生产力的影响尤为显著。

高标准农田建设的种植结构调整效应

高标准农田建设关乎国家粮食安全保障。从改善灌溉设施、促进非农就业、增加农地租入和提高农业机械化的传导机制,构建了高标准农田建设对农户种植结构调整影响的理论分析框架,进而根据2020年和2022年中国乡村振兴综合调查(CRRS)10省50县(市、区)300村4378个农户样本数据,采用面板数据双向固定效应模型,定量分析高标准农田建设的种植结构调整效应与政策异质性。结果表明:(1)高标准农田建设促使三大主粮作物种植比例提高了7.97%。(2)机制分析结果显示,高标准农田建设通过改善农地灌溉条件、增加农地租入规模和提高农业机械化来促进种植结构调整,而非农就业的传导机制未得到验证。(3)异质性分析表明,粮食平衡区、地形坡度和起伏度较大区域的高标准农田建设更能显著提高粮食种植比例。