规模化畜牧养殖对生态环境的破坏及防治

近年,畜牧养殖业蓬勃发展,过去的区域化散养已经基本不存在,养殖结构逐渐向集约化、一体化、规模化过渡,养殖规模也逐渐增大。养殖副产品肉、蛋、奶等极大满足了人们的生产生活,养殖中产生的尿液、粪污对生态环境造成极大影响。为促进规模化养殖实现绿色健康发展,该文分析规模化畜牧养殖对生态环境的破坏及防治措施。     

湟源县草地资源基本特点及开发利用

湟源县草地面积有 85 1 85 .1 3hm2 ,占全县土地总面积的 5 6.45 % ,草地资源丰富 ,牧草种类较多 ,农业生产秸秆来源广泛 ,但由于利用不当 ,造成了草地严重破坏和秸秆的浪费 ,如何合理利用草地和秸秆资源 ,扼制草地退化 ,是促进该县畜牧业发展的重要因素     

四川省退耕还林模式初探

根据自然地理分异规律、社会经济技术原理、生态学原理,分析了四川省的水土流失概况,提出了川中丘陵、盆周山地区、川西南干热干旱河谷区、川西北高山高原区的退耕还林模式。     

控制工程造价不是盲目压价

本文对工程造价管理角度进行了论述,从不同的角度分析了控制工程造价的方法,阐明如 何科学地控制工程造价。     

Genetic Engineering Approaches to Pig Production*

Modern biotechnology promises a number of new applications in animal breeding and production. Although conventional pig breeding has achieved a high level of efficiency and productivity numerous problems have been encountered with animal health and the loss of meat quality. Selection based on phenotypic performance data of individual animals does not take into account the importance of specific genes and their relevance within a complex regulatory system. In most cases it is therefore difficult to trace back the genetic origins of clinically important disorders. The application of genetic engineering techniques in pig production will facilitate diagnosis, improvement of productivity, and animal health by allowing direct genetic manipulation. Attention must be focussed on the physical and genetic analysis of the procine genome. The isolation and characterisation of genes, DNA-markers, polymorphic DNA-fragments, and their chromosomal assignment will be important prerequisites and tools for the elucidation of genetic disorders. Especially the detection of heterozygous carriers of recessive disorders and their elimination from the breeding stock will increase selection accuracy and decrease the generation intervals. But also the rapid and simple detection of infectious diseases, which is sometimes difficult if not impossible at present, will improve animal health and welfare. Although the production of transgenic animals either by DNA-microinjection into zygotes or the use of embryonal stem cells manipulated in vitro is less straightforward than DNA-based diagnosis it will play an important role in the direct manipulation of the porcine genome and genes. Breeding programmes including the use of transgenic livestock have already been developed. There is no doubt that genetic engineering has reached a degree of practical feasibility, allowing it to play an important role in pig breeding in particular and animal production in general.     

提高农用潜水电泵修复可靠性的方法

对以QY系列为主体的农用潜水电泵修复可靠性低、寿命短的问题，提出了改进措施，从而有效提高潜水电泵修复可靠性，并延长使用寿命。     

内蒙古赤峰市实行草地有偿承包的效果和经验

通过赤峰市多年来对草地有偿承包责任制的探索，阐述了草地有偿承包责任制的意义和重要性，总结了实行草地有偿承包责任制的基本做法和体会，提出了今后的设想。     

海涂实行草地农业的综合生态学方法

依据海涂独特的自然属性确定开发利用方案是保证土地资源持续生产的关键。采用降低土壤盐分、实行保护性耕作、用植物残余物覆盖地面、种植牧草防止土壤侵蚀和促使生草层土的发育，保证了以潜在形式集中的富含必需营养元素的腐殖质在土壤中聚积，改善土壤结构，提高土壤水分和养分的利用效率，并以牧草饲养家畜的土地经营活动形成了成功的草地农业生产。     

Weed:spring barley competition for applied nitrogen in pig slurry

Summary The experiments were carried out in the two spring barley fields of the organic six-course cattle:crop rotation at Foulumgaard, Denmark. The weed density was 300 and 1800 plants m⁻² respectively. Pig slurry was applied by hand in microplots by four methods: broadcasting followed by incorporation, or injected in bands to depths of 5, 10 or 15 cm. Spring barley and weeds were sampled separately six times during the tillering and elongation phase of the spring barley. The effect of application method on dry-matter (d.m.) production, nitrogen uptake and recovery of applied nitrogen in the spring barley and the weeds is reported. Slurry banding halved the weed d.m. and weed N uptake compared with broadcasting, irrespective of weed density. Weeds recovered up to 12% of the applied nitrogen, which made them a significant competitor when the slurry was broadcast and incorporated. Banding by direct injection reduced the slurry:soil contact and the weed:crop competition balance for applied nitrogen moved in favour of the crop. Thus, the crop recovery of applied nitrogen at the end of the sampling period was increased from approximately 45% for broadcast and incorporated to approximately 50% for injected slurry, and coincidental weed recovery was reduced to a maximum of 5%. As the nitrogen supply normally affects plant d.m. production, banding of slurry might well improve crop competitiveness and its tolerance to mechanical weed control.