祁连山东段六种灌丛降雨再分配特征

基于2018 年6?9 月野外采集的数据,采用野外观测与统计分析相结合的方法,研究了祁连山天祝地区金强河流域典型灌丛:山生柳(Salix oritrepha)、硬叶柳(Salix sclerophylla)、绣线菊(Spiraea salicifolia)、头花杜鹃(Rhododendron ca pitatum)、金...     

大神堂海域人工鱼礁投放对底泥细菌的影响

为探究人工鱼礁投放对底泥细菌群落结构和功能的影响,于2018年9月对2014年投礁人工鱼礁区、2018年6月新投礁区和对照区进行表层沉积物细菌16S rRNA基因测序和环境因子测定。利用高通量测序技术对细菌16S rRNA基因V4～V5区进行测序,并结合环境因子分析细菌群落的结构变化和影响因子。结果表明,投礁2个月后,新投礁区的细菌群落结构逐渐与鱼礁区趋于一致,鱼礁区和新投礁区细菌物种数和多样性指数均高于对照区,且差异显著(P<0.05)。从门类上看,变形菌门是渤海湾沉积物中丰度最高的菌种,对照区变形菌门和拟杆菌门丰度低于其他2个区域,厚壁菌门和蓝细菌丰度显著高于其他2个区域。从种类上看,对照区细菌种类明显多于其他2个区域,鱼礁投放使细菌种类发生了聚集,硫氧化菌丰度显著降低,海洋伍斯菌和脱硫细菌丰度显著升高。环境因子检测表明,与本底值和对照区相比,人工鱼礁的投放使海域底泥的粒径变小,夏季溶解氧和硫化物含量降低。功能基因和影响因子相关分析表明,鱼礁区底泥细菌的硫还原反应影响了礁区的环境,同时礁区环境的改变也影响了菌群的结构。     

盐碱胁迫对红车轴草种子萌发的影响

以红车轴草种子为试材,利用不同浓度的NaCl溶液、NaHCO_3溶液、NaCl和NaHCO_3(1∶1)混合溶液在培养皿中模拟3种盐碱环境,观察红车轴草种子的萌发状况,以期明确红车轴草的耐盐碱能力。结果表明:红车轴草种子发芽率、发芽势、相对发芽率、发芽指数、活力指数、苗鲜重和胚根长等指标,表现出随NaCl、NaHCO_3、NaCl和NaHCO_3混合溶液(1∶1)浓度的增加,总体呈下降趋势。苗鲜重和胚根长,呈现显著的负相关关系,相对盐害率与溶液浓度呈现正相关关系。NaCl胁迫下红车轴草种子萌发的耐盐浓度8.091‰,半数抑制浓度10.146‰,极限浓度12.200‰;NaHCO_3胁迫下红车轴草萌发的耐盐浓度5.483‰,半数抑制浓度7.434‰,极限浓度9.386‰;NaCl与NaHCO_3(1∶1)混合溶液胁迫下红车轴草萌发的耐盐浓度6.081‰,半数抑制浓度7.253‰,极限浓度8.425‰。蒸馏水复萌试验表明,经3种盐碱胁迫后红车轴草种子均有不同程度的复萌。综上所述,红车轴草种子具有一定的抗耐盐碱能力。     

基于供给—消耗关系的青海省高寒草地承载力时空变化分析

青海省是青藏高原的重要组成部分，因此，探究当地的草畜平衡状况，揭示其草地生态系统承载能力的时空变化趋势，对实现草地资源的可持续利用具有重要意义。本研究以青海省放牧家畜养殖为切入点，结合遥感影像数据与青海省畜牧业统计数据，对青海省草地生态系统的承载状态进行分析。结果显示：1)2005-2020年青海省放牧家畜数量共增长了25.35%；从家畜结构来看，玉树藏族自治州与果洛藏族自治州以牦牛饲养为主，海北藏族自治州、海南藏族自治州及海东市以绵羊饲养为主。2）青海省草地资源消耗量在这16年间增加了13.21%，总体表现为上升趋势，且各地级行政区间有所差异。3）青海省严重超载的地级行政区数量在2010年首次降至3个以下，整体草畜平衡状况于2013年表现最佳，草地承载压力总体有减缓趋势；分地区而言，压力增幅最明显的为海南藏族自治州，降幅最明显的为果洛藏族自治州。结果表明，2005-2020年青海省放牧家畜数量有所增加，但载畜压力有缓解趋势，省内各地级行政区在牲畜结构和压力变化方面都表现出了一定的差异性，明确了因地制宜的重要性。该结果可为青海省高寒草地生态管理及畜牧产业发展等方面提供科学依据。     

融水县“成林杉树套种灵芝”效益显著

灵芝作为药食兼用的药材需求广泛,融水县有悠久的灵芝种植历史,经验丰富,本文针对成林杉树套种灵芝做出一定阐述,为灵芝的种植提供借鉴.     

大学生就业的心理指导与职业规划

笔者根据近年来大学生就业所面临的困难,在心理调适与今后的职业规划等方面做出指导,希望大学生能正确面对就业问题,早日找到令人满意的工作,并在工作岗位上实现自己的社会与个人价值。     

新常态下如何发展现代农业——访农业部部长韩长赋

<正>随着我国经济进入新常态、改革进入深水区、经济社会发展进入新阶段,农业发展的内外环境正在发生深刻变化,加快建设现代农业的要求更为迫切。推进现代农业发展,当前最紧迫的任务是什么?我们该如何发展现代农业?笔者就这些问题专访了农业部部长韩长赋。韩长赋表示,当前,农业部门适应新常态、推进现代农业发展,最紧迫的任务就是要大力推进农业发展方式转变和结构调整。他指出,近年来我国农业现代化加快推进,但各种风险和结构性矛盾也在积累聚集,突出表现在:农业资     

羊脂制取肥皂的工艺研究

对从羊脂中制取肥皂的工艺条件进行了研究,经过净化、皂化、盐析等工艺制取出具有广阔市场前景和经济效益的化工产品肥皂。     

Response of grain yield and related agronomic traits of oilseed flax to diversified cropping rotations北大核心CSCD

This research aimed to identify a suitable planting pattern for oilseed flax production in a dry-farming region. A long-term field experiment was started in 2012 with a 4-year crop rotation cycle,designed to measure the effects on flax crop performance of previous crop,and various patterns of flax planting interval within the four-year rotation,compared with continuous flax cropping. Crop parameters measured included plant height,stem diameter,dry matter accumulation and distribution,and the experiment included six different crop rotation patterns：Flax→flax →flax→flax［（F）FFF］;Flax→wheat→potato→flax［（F）WPF］;Flax→potato→flax→wheat［（F）PFW］;Flax→ flax→wheat→potato［（F）FWP］;Flax→wheat→flax→potato［（F）WFP］and flax→wheat→potato→wheat［（F）WPW］. Results for the ninth year showed significantly increased grain yield（29. 89%-109. 57%）in crop rotation treatments compared with continuous cropping of oilseed flax. The ranking of the six tested rotations for yield was：（F）WPW>（F）FWP>（F）WFP>（F）PFW>（F）WPF>（F）FFF. The grain yield of oilseed flax was significantly affected by previous crop,frequency and years interval of flax cropping and number of years of continuous flax cropping. Yield was increased by 54. 45%-59. 29% under wheat stubble and potato stubble compared with oilseed flax stubble,and increased by 30. 66% and 109. 57%,respectively,under 50% and 25% frequencies,compared with 100% frequency. The grain yield of oilseed flax under two-year continuous cropping was higher by 29. 89% than four-year continuous cropping,and increased with increase in years interval between flax crops. Correlation analysis identified a significantly positive correlation between oilseed flax grain yield and effective capsule number,branch number and 1000-seed weight. The effective capsule number,branch number and 1000-seed weight of oilseed flax under rotation treatment were increased by 35. 88%-108. 91%,15. 47%-46. 19% and 14. 61%-16. 34%,respectively（P<0. 05）,compared with continuous cropping. In addition,the high grain yield of oilseed flax was accompanied by an increase in plant height,stem diameter and dry matter accumulation and these increases were,respectively,5. 11%-42. 24%,2. 77%-39. 92% and 31. 25%-117. 89% under the rotation regimes,compared with continuous cropping. Reduction in the number of years of continuous cropping years,change of crop stubble,decreased flax planting frequency and increased of interval between flax crops also improved flax crop performance. In summary,crop rotation improved the vigor of oilseed flax,resulting in greater plant height and stem diameter,improved dry matter accumulation and distribution,leading to increased branch number,effective capsule number and 1000-seed weight,and increase in the crop yield of oilseed flax. The results indicated that a multiple-crop rotation pattern was an effective way to avoid the yield reduction caused by continuous cropping in oilseed flax. The rotation： Flax→wheat→potato→wheat performed best among those tested and can be recommended as an appropriate cropping rotation for oilseed flax production in the dry region of northwest China. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.