种草养畜与草场建设综合配套技术

畜牧业快速发展,对于牧草资源需求量越来越大,为更好地满足畜牧业发展需求,我国提出“种草养畜”技术理念,加快草场建设,能在保障畜牧养殖业稳定发展的同时,达到良好的生态环保效益。该文分析种草养畜技术理念的意义,着重探讨种草养畜和草场建设综合配套技术。     

基因编辑技术及其在家畜生产中的应用

基因编辑技术是一类对目的基因进行靶向改变的现代生物技术,因其具有修饰效率高、特异性强、无物种限制等特点,得到了广泛的关注和应用。文章综述了4种基因编辑技术及其在家畜育种、生产性状改良、生物模型构建、优质饲草培育与供应等方面的研究与应用情况,并对该技术的应用前景进行了展望。     

广西畜禽现代生态养殖场认证存在问题及对策

为深化生态文明建设成效,推动生态养殖业的整体发展,广西自2016年开始实施畜禽现代生态养殖场认证工作,要求2020年全区90%规模养殖场都需要与现代生态养殖标准所符合。目前广西畜禽现代生态养殖场认证工作成效显著,在较大程度上推动现代生态养殖业的整体发展。但依然有一些问题存在于畜禽现代生态养殖场认证工作中,相关部门及人员需加强重视,及时探索针对性的对策。     

基于层次分析法的辽河干流水环境承载力评价研究

目前,水生态文明建设提出后,水环境承载力成为衡量地区可持续发展能力的一项重要指标。为了解辽河干流沿岸城市的水环境承载状况,以辽河干流为研究区域,采用层次分析法,建立以水资源、社会、经济、生态环境为子系统的评价体系。代入各行政分区的样本值,进行辽河干流水环境综合承载能力计算。评价了各行政分区不同现状年的承载状况。     

资料缺乏地区水功能区纳污能力计算——以都匀市清水江为例

水功能区限制纳污红线的确立是实行最严格水资源管理制度的重要组成部分。然而在河流纳污能力量化的过程中往往因为流量、流速等数据的缺失或不足导致计算结果不够准确。SWAT分布式水文模型可以通过DEM生成河网并结合气象等数据计算出河道的流量和流速,模型的这一优势能够很好地解决目标河道水文资料缺乏的问题。以黔南州都匀市清水江为例,通过构建SWAT模型和一维水质模型计算出该河流各个水功能区的纳污能力,研究结果可为该河流的水污染总量控制提供数据支撑。     

基于SD模型的长沙市水资源承载力研究

基于长沙市水资源现状,为平衡居民生活用水、经济生产用水和环境生态用水之间的关系,运用系统动力学方法,建立长沙市水资源-人口-经济-生态环境的耦合系统,模型模拟了现状延续型、经济发展型、节水治污型和综合协调型四种发展模式,选取GDP、人口数量、居民生活需水量、经济需水总量、供需压力作为主要评价指标。结果表明:第一、二、三产业分别保持10%、12%、12%年增长率且节流治污情况与现状延续型保持一致的方案,供需压力将达到节流治污方案的两倍多;经济生产用水对水资源供需压力的影响远大于居民生活用水和环境生态用水;通过适当降低人均用水量来平衡因人口数量增长而增加的居民生活用水是可行的。     

基于灰色系统理论的农村水利建设研究

水是农业发展的命脉,水利建设事关国家的粮食安全。近年来我国农村水利建设明显滞后并且存在一系列问题,但农业综合生产能力却逐年增加,农村水利是否正向作用于农业综合生产能力?基于灰色系统理论,测算出关联度系数,发现水利建设对粮食生产正向影响模式,农村水利建设对于农业综合生产力的提升以及新农村建设非常重要。我国应该科学合理安排水利投资,充分发挥其与农业发展的协同效应,以保障农民增收,实现农村的可持续发展。     

Comparison of emission estimates for non‐CO2 greenhouse gases from livestock and poultry in Korea from 1990 to 2010

It has often been claimed that non‐carbon dioxide greenhouse gases (NCGGs), such as methane, nitrous oxide and fluorinated greenhouse gases, are significant contributors to climate change. Here we nvestigate emission estimates of methane and nitrous oxide from livestock and poultry production, which is recognized as a major source of those NCGGs, in Korea over the period of 1990 through 2010. Based on the data on livestock and poultry populations, emission estimates of methane and nitrous oxide are first derived based on the Tier 1 approach. Then, the Tier 2 approach is adopted to obtain emission estimates of methane and nitrous oxide from cattle, which are known to be the largest sources of these NCGGs and account for about 70% of emissions from livestock and poultry in Korea. The result indicates that the Tier 2 estimates of methane and nitrous oxide emissions from enteric fermentation and manure management are significantly different from the Tier 1 estimates over the analysis period.     

Effects of dietary L-threonine levels on antioxidant capacity,digestive enzyme activities,and antibody production of Xinyang green-shell laying hens

Xinyang green-shell laying hens (n = 720), 32 wk of age were allocated to 5 dietary treatments groups, each of which included 6 replicates of 24 hens. The control group was given a basal corn-peanut-soybean meal diet containing 0.47% L-threonine (L-Thr). L-Thr levels of the experimental groups were 0.57, 0.67, 0.77, and 0.87%, respectively. The trial lasted 10 wk. Serum concentrations of total superoxide dismutases (T-SOD) and superoxide dismutases (SOD) were maximized at 0.67% L-Thr group. The 0.57% L-Thr group had the highest serum total antioxidative capacity (T-AOC), while the 0.67% L-Thr group had the lowest serum malondialdehyde (MDA) concentration. Hens fed 0.67% L-Thr of the diet resulted in the highest SOD and T-AOC levels in the liver. The activity of amylase and lipase in the jejunum was maximized at 0.77% L-Thr level. Hens fed 0.77% L-Thr in the diet resulted in the highest IgM and IgG levels in the jejunum. In conclusion, we suggest that a L-Thr level above 0.67% may have had an antioxidant capacity and positive effect on digestive enzyme activities and antibody production in the jejunum of Xinyang green-shell laying hens.     

外包钢加固法的安全性防范措施研究

采用外包角钢加固的钢筋混凝土柱,其加固效果和安全性与诸多因素,如加固设计、加固施工工艺、加固端锚固构造、加固角钢的增钢率与增箍率、原柱所处的应力状态、使用过程中的维护管理等有关。对外包钢加固钢筋混凝土柱过程中影响其加固效果和安全性的诸多因素的安全性防范措施进行了初步的分析研究和探讨。