不同方法对醉马草防控效果的比较

以醉马草(Achnatherum inebrians)严重发生区域为研究对象,探究物理、化学和生物方法对醉马草的防控效果,以期获得适宜的防控方法。结果表明:不同防控方法在防控当年就对醉马草种群高度、盖度、密度和地上生物量表现为一定的抑制作用;对可食牧草盖度、密度,群落多样性指数、均匀度指数表现出一定程度的促进作用。综合评价其防控效果,使用10%浓度草甘膦+皂粉(点喷)(H2)对醉马草的防除效果较好;建议在醉马草零星分布区采用人工拔除(W1),成片分布区采用高频刈割(W2);若想建立有益植物群落,则可直接补播补紫花苜蓿(Medicago sativa)+无芒雀麦(Bromus inermis)+紫羊茅(Festuca vubra)(1∶1.5∶1)(S2);化学和物理防控后,也可辅助补播,以稳定防控效果。     

Pinyon and Juniper Encroachment into Sagebrush Ecosystems Impacts Distribution and Survival of Greater Sage-Grouse

In sagebrush (Artemisia spp.) ecosystems, encroachment of pinyon (Pinus spp.) and juniper (Juniperus spp.; hereafter, “pinyon-juniper”) trees has increased dramatically since European settlement. Understanding the impacts of this encroachment on behavioral decisions, distributions, and population dynamics of greater sage-grouse (Centrocercus urophasianus) and other sagebrush obligate species could help benefit sagebrush ecosystem management actions. We employed a novel two-stage Bayesian model that linked avoidance across different levels of pinyon-juniper cover to sage-grouse survival. Our analysis relied on extensive telemetry data collected across 6 yr and seven subpopulations within the Bi-State Distinct Population Segment (DPS), on the border of Nevada and California. The first model stage indicated avoidance behavior for all canopy cover classes on average, but individual grouse exhibited a high degree of heterogeneity in avoidance behavior of the lowest cover class (e.g., scattered isolated trees). The second stage modeled survival as a function of estimated avoidance parameters and indicated increased survival rates for individuals that exhibited avoidance of the lowest cover class. A post hoc frailty analysis revealed the greatest increase in hazard (i.e., mortality risk) occurred in areas with scattered isolated trees consisting of relatively high primary plant productivity. Collectively, these results provide clear evidence that local sage-grouse distributions and demographic rates are influenced by pinyon-juniper, especially in habitats with higher primary productivity but relatively low and seemingly benign tree cover. Such areas may function as ecological traps that convey attractive resources but adversely affect population vital rates. To increase sage-grouse survival, our model predictions support reducing actual pinyon-juniper cover as low as 1.5%, which is lower than the published target of 4.0%. These results may represent effects of pinyon-juniper cover in areas with similar ecological conditions to those of the Bi-State DPS, where populations occur at relatively high elevations and pinyon-juniper is abundant and widespread.     

新常态下烟草工业企业技术中心方向性工作取向的思考

我国经济发展进入新常态以来,适应新常态,把握新常态,进而引领新常态,已成为各行各业共同面对的问题。该研究对新常态下烟草工业企业技术中心需要重点关注的方向性工作取向进行了深入思考,并提出了工作建议。     

不同行距配置对平安8号生理特性及产量的影响

[目的]研究不同行距配置对平安8号生理特性及产量的影响。[方法]以平安8号为试验品种,设置3种不同行距处理,研究不同行距配置对平安8号生理特性和产量的影响。[结果]平安8号在10 cm×30 cm行距模式下群体总茎数、叶面积指数、干物质积累、灌浆速度等均高于其他2种行距模式。[结论]实际生产中,针对株型松散的品种应采用宽窄行种植模式以提高产量。     

流量对河水滴灌重力沉沙过滤池内流速分布的影响

为研究流量对河水滴灌重力沉沙过滤池流速分布规律的影响,该文对5种不同流量下的水沙两相流流场进行了数值模拟。通过对不同流量下流速沿程分布规律、流速沿水深方向分布规律及水沙分离效率的对比与分析,可知河水滴灌重力沉沙过滤池的适宜流量范围为0.05~0.2 m3/s,进水流量越小,流速变化幅度也就越小,越有利于泥沙沉降,水沙分离效率不小于72.5%。不同流量下沉淀池中流速沿程变化规律可分成3个阶段:流速迅速增加阶段、流速缓慢减小阶段和流速迅速减小阶段。清水池中流速方向与沉淀池的相反,流速沿程减小。受进水口、出水口和固体边界,以及侧向溢流堰的影响,不同流量下河水滴灌重力沉沙过滤池中的流速沿水深方向分布规律有差别。当流量为0.05和0.1 m3/s时,远离进水口、出水口及侧向溢流堰的位置,流速沿水深方向的分布规律包含流速迅速增加、流速缓慢减小和流速恒定3个阶段,而清水池则只包括流速迅速增加和流速恒定阶段。研究可对大首部的应用提供参考。     

极小种群野生植物海南假韶子在三亚的种群分布

[目的]探讨极小种群野生植物海南假韶子在三亚的分布现状与生境调查.[方法]采用实地调查方法,对极小种群海南假韶子野生种群的植株进行调查.[结果]海南假韶子集中零星分布于落笔洞和亚龙湾热带天堂森林公园,估植株成熟个体数低于100株,在水平分布上不连续,呈聚集分布,分布较为狭窄.以种子萌发和气生根根萌的方式繁殖,但林下幼苗数量较少,幼苗自然更新不良,种群生境人为干扰严重.[结论]生境的破碎化与海南假韶子自身的生物学和生态学特性是影响种群更新的重要因素.     

辽宁水稻育种方法的三次重大突破

辽宁省水稻育种经历了三次重大突破,第一次是水稻籼粳杂交与理想株型育种,在20世纪50年代初期,辽宁省便开始了籼粳杂交育种研究,并相继开展了水陆稻杂交、地理远缘杂交研究,70~80年代成功选育出"千重浪"、"辽粳5号"、"黎优57"等品种,1978年提出理想株型育种模式;第二次是粳型杂交水稻育种,通过包台(BT)型和滇型不育系和籼粳架桥选育恢复系选育成功,1976年辽宁杂交粳稻配套成功;第三次是水稻群体育种,水稻群体育种充分利用核质互作型不育系和生态型不育系的雄性不育特性与混合父本(多品种混合播种)在田间自由授粉实现品种间或亚种间的杂交,将水稻常规育种技术与杂交稻育种技术有机地融合在一起。     

中国蔬菜出口贸易变动的趋势及影响因素分析

本文在分析中国蔬菜出口贸易最新特点的基础上,从蔬菜出口总量变动、出口去向结构、出口的国内地区来源结构、出口品种结构方面对中国蔬菜出口贸易新趋势进行分析;然后运用引力模型对蔬菜出口贸易变动的影响因素进行了实证分析。结果表明,中国和出口对象国（或地区）的GDP变量、人口变量、汇率变量、FTA变量均为重要影响因素,良好的贸易伙伴间的互惠制度安排有利于促进中国蔬菜贸易发展,减少双边贸易阻力。     

贵州省1984-2010年农区鼠情监测结果分析

为了摸清农区鼠类种群组成及种群数量变化规律,并为其种群数量预测预报和防治提供科学依据。通过分析1984-2010年贵州省30个县（市、区）农区鼠情监测结果表明,贵州省家栖鼠类和农田鼠类隶属2目（啮齿目、食虫目）3科（鼠科、仓鼠科、鼩鼱科）18种,主要集中于鼠科,占总种数的77.78%,在区系组成上以东洋界种类占绝对优势,占总种数的66.67%。褐家鼠、黄胸鼠为家栖鼠优势种,分别占总鼠数的51.26%、29.16%,小家鼠为常见种,占总鼠数的16.80%;黑线姬鼠为农田区（稻田、旱地）害鼠优势种,占总鼠数的62.57%,褐家鼠、黄胸鼠为常见种,分别占总鼠数的12.29%、14.73%,在部分地区为农田害鼠优势种,高山姬鼠为黔西北部分地区优势种。贵州省农区灭鼠的重点是黑线姬鼠、高山姬鼠、褐家鼠、黄胸鼠、小家鼠5种害鼠,应将其列为贵州省主要的监测对象。住宅区混合鼠种种群数量明显高于农田区,种群数量呈明显的下降趋势,不同年度、不同时期、不同月份、不同季节种群数量存在明显差异。根据贵州省多年来的农区鼠害测报及防治实践,明确了农区鼠害监测及综合防治的技术路线,提出了一套切实可行的农区鼠害监测技术和综合防治配套技术。     

Forecasting vole population outbreaks in forest plantations: The rise and fall of a major mammalian pest

Voles of the genera Microtus and Myodes feed on tree seedlings planted on cutover forest land in temperate and boreal forests of North America and Eurasia. This damage may have serious economic implications as well as limit regeneration of appropriate tree species in certain forest ecosystems. Prediction of vole population outbreaks and feeding damage to forest plantations, across even a limited geographic range, has yet to be achieved in North America. Thus, a major objective was a detailed analysis of changes in population dynamics of long-tailed voles (Microtus longicaudus), and to test three hypotheses (H) that vole populations would: (H₁) rise and fall in accordance with the abundance of herbaceous plants (grasses and forbs) during early vegetative succession after forest harvesting, (H₂) be positively associated with grass-seeded sites; and (H₃) incidence of feeding damage to seedlings would be positively associated with vole abundance. Voles were live-trapped for 6 years (2004–2009) from the time of harvesting on intensive sites, as well as surveyed over a range of extensive sites. Population numbers were related to habitat characteristics and tree damage in young forest plantations near Golden, British Columbia, Canada.