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1.
Theplantdiversityusuallysuppressesdiseaseepi demicsalthoughtheecologicalmechanismsarenotfullyknown .Thisecologicalprincipleismanifestedinbiodi versity richcroppingpracticesthatreducecropdiseasesinmanysubsistence farmingsystems.Modernapproach estodiseasec…  相似文献   

2.
文章综述了中国狭腹胡蜂4属11种。其中包括5个国内新记录和1新属2新种,并订正了2种狭腹胡蜂为同物异名:Stenogasterscitula(Bingham)=Eustenogasterscitula(Bingham),Holischnogastermicans(Saussure)=Eu-stenogastermicans(Saussure)。  相似文献   

3.
Manytoolssuchasboningknives,meatmincingmachinecrossknivesandgrates,cutterknivesthatarewidelyusednowadaysinmeatprocessingindustryhavelowsafetyindex.Inthisconnectionitbecamenecessarytoimprovecuttingtoolsbyincreasingtheirsafety.1 Meatmincingmachinecrosskn…  相似文献   

4.
本文记述了云南蚜茧蜂科(Aphididae)2新种:昆明前突蚜茧蜂Lysaphiduskunmingensissp.nov.和马龙少毛蚜茧蜂Pauesiamalongensissp.nov.  相似文献   

5.
本文报道了分布于黑龙江省的10种春蜓:①黄足扩腹春蜓Stylurusflavipes(charpentier)②寒冷邵春蜓ShaogomphuspostocularisepophthalmusSelys③马奇异春蜓Anisogomphusmaacki(Selys)④吉林棘尾春蜓Trigomphuscitimus(Needham)⑤新月戴春蜓DavidiuslunatusBartenef⑥臼齿日春蜓Nihonogomphusruptus(Selys)⑦暗色蛇纹春蜓Ophiogomphus(S·Str)obscurusBartenef⑧艾氏施春蜓Siebordius(S·Str)albardaeSelys⑨大团扇春蜓Sinictinogomphusclavatus(Fabricius)①0联纹小叶春蜓GomphidiaconfluensSelys。它们分属10属4亚科。其中联纹小叶春蜓和大团扇春蜓是东北新纪录  相似文献   

6.
Themammalianprotooncogenescjunandcfosaresituatedattheendofmultiplesignaltransductionpathwaysandtheactivationoftheirproducts,JunandFos,allowsacelltoalteritsmetabolicactivitiesinresponsetoeventsexternaltothecell,suchasgrowthfactorstimulation.Drosoph…  相似文献   

7.
中国发生马铃薯晚疫病菌(Phytopthora infestans)A_2交配型   总被引:31,自引:5,他引:31  
北京,内蒙古、山西和云南省等省区的10个菌株,在黑麦琼脂培养基和立马豆V—8琼脂培养基上进行交配型试验,发现其中3个菌株为A2交配型,7个菌株为A1交配型。A2交配型菌株采自内蒙古自治区和山西省。对卵孢子、藏卵器和雄器的形态进行了描述。te,a*ffn.WhetherA,existsornotinChinahasneverbeenstudiedbefore.In1995webegantheillvestigationanddiscoveredA,inChina'Thepreliminaryresultsofthestudywerepresentasfollow.TheobjectivesofthisstudyistofindoutbysurveywhethertheA,matingtypeexistsinChina,andfurtherresearchontheimmigration,movement,reasonfordevelopmentandepidemiologyoftheA,wouldbecarriedoutlater.1Materialsandmethodsl'1COllectionofsamp?  相似文献   

8.
WheatrootrotBipolarissorokiniana,oneofthemostseriousdiseases,damagesnotonlythewheatrootbutalsotheleavesandspikes,causingwheat...  相似文献   

9.
1990~1991年对采自沈阳地区的黄瓜根寄生线虫种类进行分类鉴定研究。本文共鉴定出5个属11种线虫,即:垫刃线虫属Tylenchus1个种,Tylenchusmaiua;丝尾垫刃线虫属Filenchus3个种,Filenchusbutteus,F.criniformicaudatus,F.hamatus;针线虫属Paratylenchus1个种,Paratylenchusdianthus;滑刃线虫属Aphelenchoides5个种,Aphelenchoidescomposticola,A.dubius,A.parabicaudatus,A.parascalacaudatus,A.subtenuis;真滑刃线虫属Aphelencus1个种,Aphelenchusavenae.其中,国内新记录种7个.  相似文献   

10.
云南绢蝶一新种及四新亚种(锤角亚目:绢蝶科)   总被引:2,自引:0,他引:2  
本文记述了云南绢蝶亚科一新种,即白马小绢蝶Parnassiusbiamanensis,sp.nov和二新亚种,即西蒙织蝶白马亚种Parnassiussimobiamanensis,ssp.nov.滇北织蝶人宇亚种P。brileyirenzinensis,ssp.nov.以及亚凤蝶亚种二新亚种,即匙三尾褐凤蝶冲江亚种Bhutanitisthaidinachongjiangnensis,ssp.nov  相似文献   

11.
基于养分专家系统的小麦-玉米推荐施肥效应研究   总被引:22,自引:1,他引:21  
【目的】探求冬小麦-夏玉米轮作体系科学施肥技术。【方法】采用田间试验研究了小麦、玉米养分专家系统和国际农化服务中心(Agro Services International Inc,ASI)法推荐施肥对冬小麦-夏玉米轮作周期产量、经济效益、养分积累量、肥料利用效率及周年磷钾素平衡的影响。【结果】施肥显著增加冬小麦、夏玉米产量,新郑市航空港区和鹤壁轮作周年分别增产24.75%-65.26%和8.18%-35.53%,施氮分别增产31.14%和24.40%、施磷增产11.62%和9.42%、施钾增产11.52%和8.64%,施氮、磷和钾肥平均增收9 369、4 095和3 923元/hm2。养分专家系统推荐施肥较习惯施肥,植株氮、磷和钾积累量分别增加了7.87%、12.72%和4.79%,分别增产6.63%和4.63%,增收18.27%和20.48%,产投比为4.01,与ASI推荐施肥效果相当。基于养分专家系统推荐施肥的周年氮、磷和钾肥平均农学效率分别为10.99、10.67和10.69 kg·kg-1,氮、磷和钾肥当季利用率分别为35.82%、22.30%和45.33%。冬小麦、夏玉米秸秆全量还田下,推荐磷钾肥量可实现周年磷钾素分别盈余49.6和71.5 kg·hm-2。【结论】小麦(玉米)养分专家系统推荐施肥优化了氮磷钾肥配比,促进了冬小麦和夏玉米对氮、磷、钾养分的吸收利用,在冬小麦-夏玉米轮作体系中较习惯施肥具有增产增收效果,肥料利用效率较高,实现了周年磷钾素养分盈余,方便快捷,可在冬小麦-夏玉米轮作区推广应用。  相似文献   

12.
施用腐殖酸对夏玉米产量和氮效率的影响   总被引:10,自引:1,他引:9  
【目的】研究施用腐殖酸对夏玉米产量、氮肥利用及经济效益的影响,为提高氮肥的增产效益,减少氮肥对生态环境的污染提供理论指导。【方法】在河南潮土区冬小麦-夏玉米轮作制度下,于2014年始在河南省博爱县开展田间定位试验,共设置单施磷钾肥、常规施肥、常规施肥+腐殖酸、常规施肥减氮15%+腐殖酸、常规施肥减氮30%+腐殖酸5个处理。研究不同氮肥运筹下夏玉米植株生长状况、产量及产量构成要素、氮素吸收、累积及分配、氮肥利用效率及经济效益的影响。【结果】单施磷钾肥处理与常规施肥处理相比,茎粗、穗长、穗粗、叶面积指数分别降低4.61%、8.55%、6.20%、26.91%,秃顶长增加21.60%。常规施肥较单施磷钾肥处理穗粒数、百粒重、产量分别增加8.01%、10.85%、44.45%,籽粒氮含量及氮累积量分别降低6.67%、54.07%。另外常规施肥处理产值、纯收益、产投比较单施磷钾肥处理分别增加44.45%、59.80%、43.84%。施用氮肥可以促进夏玉米植株的生长,提高夏玉米茎粗、穗长、穗粗、叶面积指数,大幅度提高夏玉米的产量,增加各部位氮素含量及累积量,进一步提高夏玉米产值、纯收益和产投比。配施腐殖酸较常规施肥处理相比可以有效改善夏玉米的农艺性状,提高夏玉米的产量,促进植株对氮素的累积和提高氮肥的利用率。其中,以常规施肥减氮15%+腐殖酸处理效果最佳,与常规施肥相比,株高、茎粗、穗长分别增加3.73%、2.30%、0.12%,秃顶长度降低22.45%,产量增加12.88%,籽粒氮含量、籽粒氮累积量、地上部总氮累积量、收获指数分别增加2.68%、25.98%、10.70%、13.79%,氮肥农学效率、氮肥偏生产力、氮肥贡献率、氮肥利用率分别增加57.46%、28.84%、22.23%、59.86%,纯收益增加8.66%。在常规施肥减氮15%的条件下配施3 000 kg·hm~(-2)腐殖酸,可有效增加夏玉米的产量,提高氮肥利用效率;但减氮30%的条件下会导致夏玉米产值和收益降低。【结论】氮肥对夏玉米的生长发育具有重要的作用,不仅可以促进夏玉米的生长发育,还可提高产量、提高植株各部位氮含量及累积量,促进氮元素的吸收及分配,提高氮肥利用率。但是过量和少量施用氮肥都会引起经济效益和生态环境效益的降低。在施用腐殖酸的基础上,适宜的氮肥用量才能获得较高的产值和收益。常规施肥减氮15%+3 000 kg·hm~(-2)腐殖酸是本研究区域最佳的施肥模式,在促进夏玉米生长发育的同时,进一步提高夏玉米产量及构成要素,促进植株对氮素的吸收及利用,提高氮肥利用率,增加夏玉米产值及纯收益。对实现现代化农业生产的高产高效、资源节约和生态环境保护具有重要的意义,是值得推荐的肥料运筹方式。  相似文献   

13.
Intercropping is one of the most vital practice to improve land utilization rate in China that has limited arable land resource. However, the traditional intercropping systems have many disadvantages including illogical field lay-out of crops, low economic value, and labor deficiency, which cannot balance the crop production and agricultural sustainability. In view of this, we developed a novel soybean strip intercropping model using maize as the partner, the regular maize-soybean strip intercropping mainly popularized in northern China and maize-soybean relay-strip intercropping principally extended in southwestern China. Compared to the traditional maize-soybean intercropping systems, the main innovation of field lay-out style in our present intercropping systems is that the distance of two adjacent maize rows are shrunk as a narrow strip, and a strip called wide strip between two adjacent narrow strips is expanded reserving for the growth of two or three rows of soybean plants. The distance between outer rows of maize and soybean strips are expanded enough for light use efficiency improvement and tractors working in the soybean strips. Importantly, optimal cultivar screening and increase of plant density achieved a high yield of both the two crops in the intercropping systems and increased land equivalent ratio as high as 2.2. Annually alternative rotation of the adjacent maize- and soybean-strips increased the grain yield of next seasonal maize, improved the absorption of nitrogen, phosphorus, and potasium of maize, while prevented the continuous cropping obstacles. Extra soybean production was obtained without affecting maize yield in our strip intercropping systems, which balanced the high crop production and agricultural sustainability.  相似文献   

14.
【目的】探究陕西关中地区麦玉复种体系下作物生产过程对秸秆还田与氮肥合理配施的响应,为实现当地粮食作物增产及资源高效利用提供理论依据。【方法】本研究于2011年10月至2016年10月,在陕西杨凌地区设置连续5年的定位试验。采用二因素裂区设计,主区为秸秆还田,设秸秆还田(S)和秸秆不还田(S0)2个水平;副区为施氮量,设常规施氮(F1)、减量施氮(F0.8)、不施氮(F0)3个水平,对冬小麦与夏玉米籽粒产量及水肥利用状况进行测定分析。【结果】秸秆还田与施氮及二者交互作用对麦玉两作物产量及其构成因素、水肥利用效率等方面有显著或极显著影响。秸秆还田较不还田处理显著提高土壤有机质、碱解氮、速效磷、速效钾含量,分别达6%-14%、8%-34%、3%-5%、3%-10%;同时显著提高麦玉播种前及收获后0-100 cm土层的储水量,播种前及收获后5季均值分别增加5%-11%、12%-15%(麦)和4%-9%、11%-17%(玉)。与不施氮处理相比,施氮显著提高土壤有机质、碱解氮、速效磷、速效钾含量;并显著提高了秸秆还田水平下麦玉播前及收后土壤储水量。在产量和水氮利用方面,秸秆还田较不还田处理分别显著提高了2012-2016 4季冬小麦和5季夏玉米产量,其中,冬小麦每年依次提高4%-6%、5%-10%、7%-10%、8%-12%,夏玉米依次为1%-2%、3%-6%、4%-7%、5%-8%、3%-7%;秸秆还田显著提高麦玉水分利用率WUE,5季均值分别增加4%-7%和8%-11%;并显著提高2012-2016 4季麦玉氮肥偏生产力PEPN、2012-2016 4季冬小麦和5季夏玉米农学利用率AEN。施氮较不施氮处理显著提高麦玉产量,且均以F1处理最高,冬小麦F1处理在两秸秆还田水平下分别较F0处理显著增产30%-38%(S)和29%-33%(S0),夏玉米为21%-25%(S)和19%-22%(S0);施氮显著提高了两作物WUE,S0水平下F1处理WUE均值最高,S水平下F0.8处理WUE均值最高;F0.8较F1处理在5季中均显著提高作物PEPN和AEN,5季均值最高的SF0.8处理较最低的S0F1处理分别增加31%和30%(麦)、30%和31%(玉)。经济效益方面,秸秆还田较不还田处理提高了麦玉净收益均值,分别为808-1 258元和733-1 212元;施氮较不施氮处理提高两作物净收益,施氮处理中以F0.8处理获得收益最大。麦玉5年净收益均呈现出SF0.8>SF1>S0F0.8>S0F1>SF0>S0F0的趋势,其中SF0.8处理下净收益均值较CK分别增加3 052元和2 145元。【结论】长期秸秆还田配减量施氮在保证冬小麦及夏玉米维持较高产量的情况下,显著改善作物水肥利用情况。综合考虑作物产量、水肥利用效率及经济效益,不同处理间以秸秆全量还田配施减量氮肥处理效果最优。  相似文献   

15.
在四川盆地东北部中丘区的棕紫泥旱坡地上,研究了"麦/玉/苕"旱三熟增间大豆的经济效益和土壤生态效益.结果表明:"麦/玉/苕"间种大豆结合秸杆还田耕作,在大春粮食增产或不减产基础上,经济效益显著提高;土壤容重降低、养分提高,特别是有机质、速效磷、速效钾明显增加.认为改进种植模式与发展大豆生产相结合,是提高旱坡地综合效益的良好途径.  相似文献   

16.
With the aim of increasing the grain crop yield and the level of soil nutrition in the fluvo-aquic soil in North China, the effects of long-term application of K fertilizers and straw returning on crop yield and soil nutrient supplying capacity were investigated in the long-term K localization experiment (1992–2009). The results revealed that wheat and maize responded to K fertilizer in an identical manner and the average yield of wheat and maize for 17 years were NPKSr > NPK > NPSr > NP. Application of K fertilizer on the basis of NP fertilizers could increase the yield of wheat and maize while the grain and straw yields in each treatment were significantly higher for maize than for wheat. The yield of wheat and maize was increased by 6.74% and 22.32% respectively when applied with NPK fertilizers compared to NP fertilizers. With the NPSr fertilizing mode, the yield of wheat and maize was increased by 2.84% and 10.62% compared to the NP mode respectively. The NPKSr fertilizing mode gave the best yield for wheat and maize, resulting in 10.34% and 23.81% increase respectively compared to the NP mode. The yield stability of wheat was significantly higher than that of maize. Under the condition of long-term fertilization, the K uptaken by wheat and maize was degressive by the sequence of NPKSr > NPSr > NPK > NP, mainly deposited in the straw but not in the grain. In this work, the soil natural ability for applying K was gradually reduced as the planting years proceeded and the changes were fitted by linear equations. The natural supply ability of K element in land planted wheat was higher than that in land planted maize.  相似文献   

17.
少耕免耕及秸秆覆盖在改善生态环境、培肥地力、提高作物产量和提高资源利用效率等方面有重要作用。试验设置4个耕作处理,分别为常规耕作、旋耕、耙耕和免耕;施氮量设置3个水平,分别为常规施氮量的100%、75%和50%,以研究耕作方式和施氮量对小麦、玉米产量及产值的影响。结果表明,随着施氮水平的递减小麦公顷穗数降低,小麦、玉米产量降低,总产量下降;旋耕、耙耕和免耕处理的小麦穗粒数随施氮水平的递减而降低,而千粒重随施氮水平的递减而有增加趋势,玉米的千粒重与施氮水平变化趋势基本一致;常100、耙100和免100处理的产量最高,旋100、常75和免75次之,而耙100和免100处理的净产值最高,高于常100。因此,耙100和免100的经济效益最高,具有较高的推广价值。  相似文献   

18.
[目的]在有限的耕地上,在基本不影响大宗粮食作物生产的前提下,利用0.5熟光热资源,扩大马铃薯种植面积。[方法]通过填闲复种和间套增种,分区构建马铃薯多季高效种植新模式,提高马铃薯单产和效益。[结果]在平原丘陵区稻田构建"秋马铃薯/油菜-水稻"、"冬马铃薯-水稻-秋马铃薯"和"秋(冬)马铃薯-水稻"等3种新模式;在平原丘陵区旱地构建"春(冬)马铃薯/玉米/甘薯"、"春(冬)马铃薯/玉米-秋马铃薯"和"小麦+冬马铃薯/玉米/甘薯"等3种新模式;在高原山区构建"春马铃薯/玉米"新模式。[结论]新模式复种指数200%~300%,积温利用率68.9%~93.4%,光能利用率0.98%~1.59%,秸秆利用率50%~100%。与传统种植模式相比,新模式全年产量提高2.6%~93.0%,效益增加15.8%~284.3%。马铃薯多季高效种植模式已成为四川农作物增产增收的主体种植新模式。  相似文献   

19.
【目的】全球气候正以变暖为主要特征发生显著变化,探究气候变化对黄淮海地区夏玉米-冬小麦种植制度的影响,为制定合理的应对措施提供理论依据。【方法】通过气象站点观测值的加权平均和一元线性回归分析黄淮海各省市地区1992—2013年来的气候变化特征。利用农业气象站点多年长期观察的夏玉米-冬小麦物候数据,通过加权求平均,分析气候变暖背景下夏玉米-冬小麦的生育期和茬口推移情况。采用一元线性回归分析1992—2013年来黄淮海地区夏玉米-冬小麦周年产量变化。同时利用非线性回归分析法和面板数据敏感性分析法分析气候变化对黄淮海地区夏玉米-冬小麦周年产量的影响。【结果】1992—2013年来,黄淮海地区温度整体呈现波动上升趋势,降水总量变化趋势不明显,但区域差异显著。在气候变化的背景下,黄淮海地区夏玉米-冬小麦种植模式发生明显改变:冬小麦播种时间推迟,生育期存在缩短趋势,不同地区缩短2—5 d不等;夏玉米播种时间南部推迟而北部提前,收获时间总体呈现推迟趋势,整个黄淮海地区生育时长未发生明显变化。茬口时间因夏玉米-冬小麦生育期的推移呈现不同程度延长,造成了气候和土地资源的浪费。1992—2013年间黄淮海地区夏玉米-冬小麦单产呈显著上升趋势,多数省份达到显著水平。非线性敏感性分析表明,最低温度、最高温度和平均温度对夏玉米-冬小麦产量的影响基本表现为同时增产或同时减产的一致性。冬小麦产量受最低温度的影响最为显著,东南部的江苏省和山东省减产明显,而北部河北省和西部河南省表现为增产。温度升高除对河南省夏玉米有增产作用外,其他省份夏玉米产量均出现不同程度的降低,这可能与温度升高的幅度不同和降水的区域性差异有关。降水量对夏玉米-冬小麦产量影响存在地区差异。总体上气候变暖对周年单产影响表现为北部增产,而南部减产,因而选择适宜早播且生育期长的夏玉米品种对保障周年产量具有重要意义。【结论】气候变暖背景下,黄淮海地区冬小麦播种时间推迟,生育期缩短,夏玉米生育期北部延长而南部缩短,生育期的推移导致茬口时间延长,造成了气候资源和土地资源的浪费。1992—2013年间夏玉米-冬小麦周年产量显著提高。温度升高和降水增加对产量的影响存在区域差异,整个区域平均来看升温使夏玉米减产,冬小麦增产;降水增加有利于黄淮海北部地区夏玉米的产量形成,对南部地区夏玉米产量则存在不利影响,而对黄淮海大部分地区冬小麦的产量形成不利。  相似文献   

20.
Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha~(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha~(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.  相似文献   

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