Sheep farming intensification and utilization of natural resources in a Mediterranean pastoral agro-ecosystem

The research was carried out in the “Sierra y Cañones de Guara” Natural Park, a protected mountain area located in the Central Pyrenees (Huesca, Spain). In this territory, a notorious recession of agricultural activities has been observed in recent decades, which has originated changes in the type and intensity of land utilization and, simultaneously, led to environmental and landscape degradation.The main goal of this research was to analyse what characteristics of the current sheep farming systems could explain different patterns of utilization of the grazing resources. Information was obtained through direct interviews with all sheep farmers that used the grazing resources of the Park in 2000 (n = 53). Specific information on grazing management (grazing areas, grazing periods, number and type of grazing animals) was collected together with data on family characteristics, labour, flock management, land use, continuity, recent changes in farming and farmers opinions. Principal Components Analysis was used to examine relationships among original variables. Farming systems were then characterized in four homogeneous groups using Cluster Analysis. Finally, a Logistic Regression allowed determining relationships between the level of intensification of management and several social and technical features.Intensification of farm management was linked to the type and intensity of land utilization: the higher the intensification of the reproduction system the shorter the grazing period and the lower number of grazing animals. Besides, chances of continuity were critical in some groups of farms, especially in some of the most extensive ones, while many farms with good chances of permanence showed more intensive management strategies but lower utilization of grazing resources. In this type of agro-ecosystems, rural development policies with conservation purposes should focus on farming systems with more environmentally desirable management strategies, and consequently enhance their chances of continuity.     

环境中重金属污染及其对植物生长发育的影响

总结了重金属在环境中污染途径、种类，以及对植物生长发育、代谢等影响，指出了对常见重金属污染土壤后的治理措施。     

艾比湖及周边地区环境演变与对策

本文讨论了艾比湖地区近代自然环境演变及出现的湖泊急剧干缩、灾害性天气增加、沙漠化扩展，植被恶性演替等环境问题，指出近代环境变化主因是人为活动，人工绿洲内部的良好环境与外部的荒漠环境反差更加显著。对恢复和稳定区内环境提出了维持湖泊面积，节水农业，恢复荒漠林，控制人口等项措施。     

论干旱区水资源与生态环境问题

本文以我国西北和中亚地区（哈萨克斯坦南部）为主，论述开发利用水资源过程中所出现的生态环境的变化，探讨合理开发、利用水资源与生态环境的关系。     

Effect of environment stress on reproductive physiology in Chinese tree shrew

AIM:To study the effect of environment stress on reproductive physiology in Chinese tree shrew．METHODS: 30 animals were divided at random into three groups.Group 1: 10 of 30 animals served as control;group 2 and 3 the 8 and 12 of 30 animals served as experiment and housed in small cage.The levels of the testosterone(T) and estradiol (E₂) were determined by the method of radioimmunoassay and section preparation of testis was observed by light microscope after living in the reduced scope for 21days.RESULTS: The result showed that the levels of the testosterone in group 2 and 3 were decreased by 49.4% and 80.3%,respectively,compared to that in group1.The convoluted tubules of testis in group 2 and 3 were damaged and only a few spermatogonia was doserved.CONCLUSION: Social environment stress has significantly inhibitory effect on testosterone formation and destroy the testis structure of Chinese tree shrew.     

论绿色畜禽产品生产

提出了发展绿色食品及其畜禽产品的必要性,以及发展绿色畜禽产品所要解决的两大问题,受污染问题和污染环境问题;本文叙述了绿色畜禽产品生产的一些方法和途径以及转基因生物技术在发展农业及绿色畜禽产品中的应用前景。     

宁夏土地生态环境的主要问题及对策

<正> 1.主要问题土地是由自然地理所有要素(地质、地貌、气候、土壤、植被等)组成的自然综合体,具有综合反映环境质量的特性。由于土地各组成要素在地域空间上的量值及其组合作用的差异,因而环境质量及环境治理方向也会因地域而不同。就宁夏自治区而言,大致可以划分出四大类型区:1.1 宁南黄土丘陵区以水蚀为主,水土流失严重,土地生态环境脆弱     

可持续发展下的绿色投入产出核算研究

为了能够反映可持续发展的状况,反映资源产业、环保产业与我们通常意义上的经济产业部门之间的经济技术联系,我们可以运用投入产出分析的方法,设计可持续发展下的绿色投入产出表,研究资源环境与经济的投入产出关系。通过分析,可以研究资源、环境与经济的综合平衡关系,找出经济发展过程中各经济部门对环境所造成的损害,为可持续发展宏观决策和产业结构调整提供依据。     

植物种群结构特征及其对环境的响应

种群结构是种群最基本的特征,通过论述种群结构的特征,从环境因子方面来阐述对其的影响以及种群对环境的响应,最后论述了植被的种群结构特征在时空上的连续性。     

畜禽舍用夹层保温复合板的性能试验

在调查分析基础上,选择了竹笆板,玻璃钢做面层,聚苯乙烯为芯层,作为复合板材的组成材料。对其复合工艺等方面进行了较深入的研究,进行了复合板块各方面指标的性能试验。