幼苗期摘心对高产春大豆根系生长和产量的影响   总被引：1，自引：0，他引：1  

楚光红  章建新  王聪  赵占营 《干旱地区农业研究》2021,39(2):102-110

试验以主茎型高产春大豆‘新大豆27号’为材料,分别在真叶期(TP)和第一复叶期(CP)摘心,同时设置15(D_1)、18(D_2)、21(D_3)、25(D_4)、30(D_5)万株·hm~(-2) 5个不同密度(复叶期)摘心试验,以此探究近代高产春大豆根系生长和产量对幼苗期摘心的响应规律。结果表明:CP处理总侧根干质量、总侧根长度和总侧根表面积均显著增加,盛荚期(峰值)较对照(CK_1)分别增加了18.66%、14.94%和17.49%,且0～20、20～40 cm和40～60 cm的根系活力分别提高了14.00%、15.43%和15.41%,而TP处理的根系活力则分别下降了8.46%、5.03%和4.82%;CP处理后单株荚数和单株粒数分别高于TP处理6.59%和4.37%,但分别低于对照14.00%和14.02%;TP和CP处理的百粒重分别较对照增加了10.08%和12.25%,TP处理减产5.16%(p0.05),CP处理减产2.64%(p0.05);降低摘心密度(D_3～D_1),则单株结荚节位数、单株荚数、单节荚数和单株粒数会显著增加,当密度下降30.62%(D_2)时群体荚数和群体粒数仅分别下降了2.37%和2.76%(p0.05),而百粒重和产量分别提升了8.92%和5.90%(p0.05),若继续降低密度产量则下降。CP处理减产不显著的主要原因是百粒重显著增加补偿了群体荚粒数的减少,而降低摘心密度D_2表现为增产,说明摘心对产量的补偿效应是分枝数增加导致单株荚数(粒数)和百粒重显著增加的结果。由此认为,第一复叶期摘心对高产春大豆产量形成有显著促进作用。  相似文献   

混播草皮缓冲带对农田径流氮磷去除效果研究     

何聪  刘璐嘉  王苏胜  周明耀 《江西农业学报》2014,(3):25-28

草皮缓冲带作为防治农业面源污染的一种有效技术得到越来越广泛的应用。以去除氮磷效果最佳为目标,提出了将草皮混播技术运用到缓冲带的构建中,并筛选出了合理的草种混播比例。根据豆科牧草和禾本科牧草的相容性,选择扬州本地具有推广价值的草坪草本植物白花三叶草(Trifolium repens)与高羊茅(Festuca arundinacea)作为供试植被,研究不同草种混播比例下草皮缓冲带对农田径流污染物的去除效果。结果表明,在总氮、总磷进水浓度分别为7.78~27.22mg/L和0.47~1.61 mg/L的试验条件下,混播草皮的存在明显提高缓冲带对污染物的去除效果,且对渗流水污染物的去除效果明显高于径流,当白花三叶草与高羊茅混播比例为1∶3时,缓冲带对径流水和渗流水中总氮、总磷的去除效果较好,且植物生长状况良好,具有较好的环境适应性。  相似文献   

纳米ZnO对小鼠肺的毒性效应     

王群林  李岩  许聪  卞伟华  张小华 《安徽农业科学》2014,(31):10976-10978

[目的]采用长期纳米氧化锌腹腔内注射,初步测定纳米氧化锌颗粒对小鼠一般状态、肺及炎症介质的慢性影响。[方法]取25 g左右健康小鼠22只,雌雄各半,随机分为空白对照组和试验组,每组11只。试验组小鼠给予腹腔注射83 mg/ml纳米氧化锌悬浊液各0.15 ml,连续注射7 d,对照注射等量生理盐水,注射药物结束3 d后观察小鼠一般状态并取材,肺叶称重测定湿干比(W/D),采用HE染色在光学显微镜下观察肺组织形态。采用ELISA法检测支气管肺泡灌洗液及血清中细胞间粘附分子-1(ICAM-1)和肿瘤坏死因子-α(TNF-α)含量。[结果]与对照组小鼠相比,试验组小鼠死亡率增加,平均体重明显减轻,肺的湿干比增高;血清及灌洗液中炎症因子TNF-α及ICAM-1含量显著升高,存在显著性差异(P0.05);显微镜下可见肺组织有损伤。[结论]长期纳米氧化锌腹腔注射可对小鼠肺产生慢性不良影响。  相似文献   

不同浓度盐溶液及盐渍土对毛细水上升影响的研究   总被引：1，自引：0，他引：1  

王聪  张平  谢长青  吴昊 《节水灌溉》2014,(12)

通过观测毛细水上升速度和高度,研究不同浓度盐溶液和盐渍土对毛细水上升的影响,并对这些影响因素进行机理分析。研究结果表明:同一颗粒级配下不同浓度盐溶液毛细水上升在初始阶段受盐浓度的影响较大,最终上升高度随浓度的增加而下降;盐渍土毛细水上升高度低于无盐土样,开始阶段盐渍土毛细水上升速度低于无盐土样,随着时间的推移上升速度趋于一致。  相似文献   

New farmers’ efforts to create a sense of place in rural communities: insights from southern Ontario,Canada     

Minh Ngo  Michael Brklacich 《Agriculture and Human Values》2014,31(1):53-67

This research situates new farmers within the counter-urbanization phenomenon, explores their urban–rural migration experiences and examines how they are becoming a part of the rural agricultural landscape. Key characteristics in new farmers’ sense of place constructions are revealed through an ethnographic study conducted in southern Ontario, Canada, during the summer of 2009. Using a sense of place framework comprised of place identity, place attachment, and sense of community, this research details a contemporary concept of place to provide a fresh perspective on new farmers. It uncovers underlying motivations, goals, and values attached to rural agricultural landscapes as well as the “everyday” interactions and challenges experienced by those transitioning into rural farming communities. New farmers are found to draw unevenly from both the physical and social landscape of the urban and rural environments in the creation of a sense of place. This finding raises important questions about the socio-spatial dynamics that underscore the place of food and the local food movement.  相似文献   

Development and validation of a 3ABC antibody ELISA in Australia for foot and mouth disease     

A Colling  C Morrissy  J Barr  G Meehan  L Wright  W Goff  LJ Gleeson  B van der Heide  S Riddell  M Yu  D Eagles  R Lunt  S Khounsy  Ngo Than Long  Pham Phong Vu  Nguyen Than Phuong  Nguyen Tung  W Linchongsubongkoch  J Hammond  M Johnson  WO Johnson  H Unger  P Daniels  JR Crowther 《Australian veterinary journal》2014,92(6):192-199

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Seroprevalence investigation of bovine brucellosis in Macenta and Yomou,Guinea     

Seydou Sylla  Youssouf Sidimé  Yixue Sun  Sayon Doumbouya  Yanlong Cong 《Tropical animal health and production》2014,46(7):1185-1191

Brucellosis is one of the world’s major zoonotic diseases associated with reproductive disorders and a potential infection of human. Brucellosis leads to serious economic losses due to late-term abortion, stillbirth, weak calves, and sterility. In Guinea, the data on brucellosis was only detected as far back as 10 years ago. The purpose of this study was to estimate the prevalence of bovine brucellosis in the provinces of Macenta and Yomou of Guinea. A structured questionnaire was used in the clinical study, and 345 cattle were clinically examined. Three hundred serum samples were initially subjected to the Rose Bengal test (RBT); the positive results of which were confirmed by the complement fixation test (CFT). The investigation indicated that farmers had little information on brucellosis. Hygroma, abortion, sterility, and placental retention were the observed symptoms. Of the 29 RBT-positive samples, 26 were confirmed by CFT. The prevalence of brucellosis in Macenta and Yomou was 12 and 5.33 %, respectively. In both provinces, the prevalence mean was 8.67 %. This study highlighted the immediate necessity to carry out a strengthened surveillance of human and animal brucellosis to obtain as many data as possible in order to establish strategies for prevention and management of brucellosis in Guinea.  相似文献   

Comparative analysis of receptor-binding specificity and pathogenicity in natural reassortant and non-reassortant H3N2 swine influenza virus     

Yanlong Cong  Yixue Sun  Weili Wang  Qingfeng Meng  Wei Ran  Lisai Zhu  Guilian Yang  Wentao Yang  Lihua Yang  Chunfeng Wang  Zhuang Ding 《Veterinary microbiology》2014

Genetic reassortment between human and avian influenza viruses can create pandemic viruses. Influenza surveillance of pigs in Jilin Province, in China during 2007–2008 revealed that there were two distinguishable genotypes: a human-like H3N2 genotype and a double-reassortant genotype derived from the human H3N2 and avian H5 viruses. In this study, viral infection potential, replication kinetics, and pathogenicity were compared. The solid-phase binding assay demonstrated that both viruses prominently maintained a preference for the human-type receptor and the reassortant A/swine/Jilin/37/2008 (Sw/JL/37/08) showed relatively higher binding affinities than the non-reassortant A/swine/Jilin/19/2007 (Sw/JL/19/07). Replication kinetics showed that Sw/JL/37/08 had higher replicability in MDCK cells than Sw/JL/19/07. The mouse experiments clearly revealed that Sw/JL/37/08 had higher virulence than Sw/JL/19/07 as measured by more significant body weight loss, higher viral lung load, delayed viral clearance from lungs, and more severe pulmonary lesions. Sequence analysis indicated that the absence of glycosylation sites at residue 126 of HA and 93 of NA, as well as the characteristic NS1 C-terminal PL residues of ESEV may account for the increased replication and pathogenicity of Sw/JL/37/08. These results may imply that human may have infection risk by the reassortant swine influenza virus and emphasize the necessity for enhanced viral surveillance strategies, which monitor reassortment events in nature to reduce the public health threat posed by influenza viruses with the potential for human-to-human transmission currently circulating in pig populations.  相似文献   

Soil fertility affected by land use history,relief position,and parent material under a tropical climate in NW-Vietnam     

Gerhard Clemens  Sabine Fiedler  Nguyen Dinh Cong  Nyuyen Van Dung  Ulrich Schuler  Karl Stahr 《CATENA》2010

In Vietnam as much as half of the total land area is already degraded by soil erosion and nutrient depletion. In particular, degradation due to deforestation is increasingly affecting mountainous areas in north-western Vietnam. The necessity to safeguard the farmers' livelihoods requires sustainable resource management, which firstly requires a qualitative and quantitative evaluation of resources. The objectives of the present study were to (1) identify the dominant soil types and their vulnerability using elicitation of local soil knowledge, (2) characterise the physical and chemical properties of the soils and (3) link them to the relief position and land use in order to (4) initiate sustainable soil use based on recommendations deduced from objectives (1) to (3). These objectives were achieved also by the elicitation of local knowledge. The final aim of the study was to initiate sustainable soil use based on recommendations for sustainable land use scenarios. The Chieng Khoi commune in Son La province of northern Vietnam was chosen as representative for other erosion-prone Southeast Asian sloping areas. In a participatory approach, combining local and scientific knowledge, sixteen sites were selected, representative for distinct relief positions, parent material (sand stone and silt stone), land use history, and erosion hazard. Chemical (e.g. content of organic matter, nitrogen, cation exchange capacity, base saturation, and plant available phosphorous) and physical properties (e.g. air capacity, plant available water) were used to estimate soil fertility. The predominant reference soil groups in the study area are Alisols and Luvisols, with a high diversity in respect to soil fertility. These soils are locally named ‘red soil’ and ‘black soil’, respectively. Although the main physical processes are erosion and selective sedimentation, farmers tend to underestimate their impact and causes, whereas soil quality was well-evaluated. Soils with high fertility were found on less eroded upper parts of hills and at sites, where agricultural use started only recently. Once degraded by cultivation practices, soils derived from sandstone did not recover even after more than 50 years of fallow. As a result of unsustainable land use, soils on middle and lower slopes are often affected by severe soil erosion, whereas foot slope soils suffer from accumulation of eroded infertile subsoil material as well as stagnic conditions. This study showed that unsustainable land use at upslope landscape positions has a severe impact on downslope areas. The elicitation of local knowledge facilitated the identification of such hot spots, allowing the implementation of spatially targeted conservation measures.  相似文献   

热泵-热风组合干燥方式对干制海参品质的改善   总被引：8，自引：2，他引：6  

丛海花  薛长湖  孙妍  孙兆敏  刘方 《农业工程学报》2010,26(5):342-346

为了提高干制海参的品质,该文在热风干燥的基础上,利用热泵－热风组合干燥的方式干燥腌渍海参,对不同干燥方式下海参的干燥特性（干燥特性曲线,收缩系数和产品品质）进行测定,对干燥结束后海参的复水品质（复水倍数,流变学参数,感官评价）与传统的热风干燥进行分析比较,结果表明：组合干燥海参的平均收缩系数最小,为16.64,而平均复水倍数为10.18,远高于热风干燥产品;产品流变学特性及硬度,弹性,柔韧度,黏性均较热风处理后海参理想。结果表明：组合干燥可以明显提高干燥后海参的复水倍数和复水品质,产品的感官品质好。  相似文献