林业病虫害综合治理方法

随着工业与经济建设的不断发展,我国环境污染问题越来越严重,森林系统遭到破坏,林业病虫害问题频繁发生,严重影响到我国可持续发展。本文将探析新形势下林业病虫害的综合治理问题,以进一步提升我国林业建设水平,促进我国生态环境建设的进一步发展。     

影响农村规模养羊效益的因素浅析

通过调查部分规模养羊场,找出了规模养羊收入偏低的主要原因,并提出了提高农村规模养羊效益的途径。     

基于数值模拟的太湖流域地区节水条件下水田灌排水量研究

太湖流域内农业用水粗放,水利用效率低下,农业面源污染严重,推广水稻节水灌溉势在必行。为了研究水稻节水灌溉对太湖流域用水总量控制的影响效应以及对太湖流域水资源量和水环境的影响效应,需要弄清在不同保证率下节水灌溉和淹水灌溉单位面积的灌溉水量和排水量。改进了逐日水量平衡法中蒸散发项和渗漏项的计算方法,并对该方法中各个参数的确定做了说明。最后以杭嘉湖区为例,选用1956-2000年系列资料模拟灌溉排水过程,同时采用P?Ⅲ型曲线计算不同保证率下节水灌溉和淹水灌溉的灌溉水量,并比较了两者的效益。     

一类传送带问题解的存在性

本文通过变分法考虑了一类带有异号源和反作用力的传送带问题,利用Ekeland变分原理和分析技巧获得了此类问题正解的存在性.特别地,当反向作用力的正系统足够小时,该问题存在至少3个非平凡解.     

寿光黑鸡成纤维细胞的体外培养与冷冻保存(英文)

[Objective] The aim of this study was to establish the in vitro culture system of chicken fibroblasts.[Method] Tissue explant method and enzymatic digestion method were used to separate and culture chicken skin fibroblasts respectively.The rate of cell growth,cryopreservation and recovery were compared.[Result] The primary chicken fibroblasts prepared by enzymatic digestion grew faster and converged together to form monolayer on 5 d post preparation;the passage cells prepared by these 2 methods grew at similar speed and formed monolayer within 2-3 d;homogeneous fibroblasts could be obtained by trypsin digestion and repeated attachment for 3-4 passages;there were 75%-80% of cells survived after cryopreservation and recovery;the growth curves of embryonic fibroblasts and skin fibroblasts were all normal and the two kind of cells still retained the normal number of chromosomes even at the twelfth passage.[Conclusion] The feeder layer cells needed for establishing ES cell lines could be obtained by culturing chicken fibroblasts through both tissue explant method and enzymatic digestion method.This study provided a basis for the successful establishment of ES cell lines.     

不同品种玉米生物产量及青贮后营养变化规律分析

本试验对青贮专用玉米品种雅玉8号和生产上常用的籽粒玉米郑单958、浚单20不同收获时间的生物产量及青贮后主要营养成分进行了测定,结果表明:这三个品种在青贮后主要营养指标差异不明显,基本符合国家青贮玉米标准,雅玉8号生物产量高于其他两个普通玉米品种,但酸性洗涤纤维含量略超国家标准。     

林业病虫害的防治对策

林业资源是我国重要的自然资源,也是我国经济来源之一。我国林业资源大大减少,除了受自然天气的影响,还受到了大量病虫害的影响,为提升林业的产量,重点关注病虫害的解决办法。