浅析河北省太行山区生态经济沟的可持续发展

河北省太行山区生态经济沟经过20多年的发展已取得了一定的成绩,在促进农业经济发展方面发挥了重要作用.面对新的形势,如何推进生态经济沟健康持续发展是一个重要课题.文章以河北省太行山区生态经济沟发展的现状为切入点,以生态经济相互协调为前提,以山区环境和资源、人口为依据,提出了建设农村高效农业,促进农村支柱产业发展等一系列建...     

用户行为驱动的网页布局自动调整的研究

逻辑观是困扰当前中国逻辑史研究的根本性问题。两千多年来，逻辑的名称虽几经变化，但对命题形式、推理形式及其有效性的分析，始终是西方逻辑不变的主题。由于中国逻辑史研究是基于西方逻辑的传入而产生的，因此，西方逻辑的逻辑观应当成为中国逻辑史研究的基本遵循。     

轻钢结构抗震节能体系在“塞上农民新居”中的应用

针对宁夏地区农民传统住宅抗震性差，建筑外围护结构保温性能差，采暖系统能源消耗量大，环境污染严重等问题，提出采用轻钢结构配以轻质保温板材的轻钢结构抗震节能体系，以期为宁夏农村住宅设计提供指导性建议。     

膜下滴灌在冀西北干旱半干旱区的应用研究

根据对位于冀西北的张家口地区的节水灌溉现状以及发展状况的调查,分析了该地区应用膜下滴灌的适应性,计算了该地区应用膜下滴灌的节水潜力,总结了在推广应用中存在的困难,并提出相应的措施。     

农林类高校学风问题及建设对策探讨

从学习目的、学习态度、学习纪律、学习方法、学习兴趣、学习氛围等方面提出并分析了农林类高校的学风问题,从提高认识、抓实专业思想教育、深化教学改革、坚持导管结合、加强校园文化建设等方面提出了加强学风建设的思路与对策。     

土地开发整理前期地形图测绘调研分析

通过对重庆市彭水县高谷镇共和村土地开发整理测绘项目的实地调研分析,对该项目进行了归纳总结,介绍项目的测绘技术和流程,旨在为今后推进农村土地开发整理测绘提供实践依据。     

Effect Of Replacing Fish Meal With Blood Meal On Chemical Composition Of Supplement For Nile Tilapia (Oreochromis Niloticus)

The objective of the work was to evaluate the effect on the nutrient content of replacing fish meal (FM) with blood meal (BM) in fish supplement. Three isonitrogenous diets (35% crude protein) were formulated using FM as the main source of animal protein (BM0); 50% replacement of FM with blood meal (BM50); or 100% replacement of FM with BM (BM100). The chemical composition (ash, crude protein, crude fat and crude fibre) and amino acid composition were determined. Replacement of FM with BM did not affect the proximate composition of the diet apart from ash content which decreased with the level of substitution. Substituting fish meal with blood meal reduced the levels of methionine, lysine, isoleucine, leucine, proline, valine and increased the levels of arginine, phenylanine and alanine in the diet. Amino acid indices revealed that BM0 had more amino acids with the highest chemical scores followed by BM50 and BM100. In all the diets, methionine was the most limiting amino acid. The essential amino acid index of the diets reduced with the level of replacement of FM (0.94, 0.88 and 0.77). The study showed substitution of up to 50% FM with BM gave a useful protein diet and 100% gave almost a poor protein diet.     

吴忠市利通区西瓜果斑病的发生及防控措施

详细介绍了利通区西瓜果斑病的发生、危害症状及发生前后宜采取的各种防控措施及预防措施。     

Impact of soil engineering by two contrasting species of earthworms on their dispersal rates

By burrowing galleries and producing casts, earthworms are constantly changing the structure and properties of the soils in which they are living. These changes modify the costs and benefits for earthworms to stay in the environment they modify. In this paper, we measured experimentally how dispersal behaviour of endogeic and anecic earthworms responds to the cumulative changes they made in soil characteristics. The influence of earthworm activities on dispersal was studied in standardised mesocosms by comparing the influence of soils modified or not modified by earthworm activities on earthworm dispersal rates.The cumulative use of the soil by the earthworms strongly modified soil physical properties. The height of the soil decreased over time and the amount of aggregates smaller than 2 mm decreased in contrast to aggregates larger than 5 mm that increased. We found that: (i) earthworm activities significantly modified soil physical properties (such as bulk density, soil strength and soil aggregation) and decreased significantly the dispersal rates of the endogeic species, whatever the species that modified the soil; (ii) the decreasing in the dispersal proportion of the endogeic species suggests that the cost of engineering activities may be higher than the one of dispersal; (iii) the dispersal of the anecic species appeared to be not influenced by its own activities (intra-specific influences) or by the activities of the endogeic species (inter-specific influences). Overall these results suggest that the endogeic species is involved in a process of niche construction, which evolved jointly with its dispersal strategy.     

基于“3S”技术的辽宁省某尾矿库扩容工程生态影响预测与评价

以辽宁省某尾矿库为例,基于GIS技术,利用2010年的TM遥感影像及地形图,预测该尾矿库扩容后的生态影响。分析结果显示:尾矿库扩容工程对生态的影响主要体现在土地利用、植被、生态景观和地形地貌的变化4个方面。