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1.
贵州喀斯特地区人工湿地应用存在的问题与解决对策   总被引:1,自引:0,他引:1  
人工湿地是近几十年来发展起来的一种新型的污水生态处理技术,近年来在有条件的地方得到了推广应用。为改善贵州省居民饮用水水质,贵州省政府实施了乡村清洁工程——利用人工湿地技术处理农村生活污水。结合农村生活污水及贵州省喀斯特地质的特点,介绍了人工湿地在贵州省农村污水处理系统中的应用,并分析了人工湿地在贵州省处理农村生活污水中存在的问题,针对这些问题提出了相应的解决措施。  相似文献   
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《Soil Technology》1994,7(4):303-317
Amendments that alter clay dispersion and aggregate disintegration also change soil porosity and sealing. Soils selected for this study had increased (Mollisol, Oxisol, and Vertisol), decreased (Oxisol), or non-affected (Oxisol and Ultisol) water infiltration when fluidized bed combustor bottom-ash (FBCBA) was surface applied to decrease dispersion. Soil was sieved to pass 8-mm, packed into small erosion pans, prewetted by capillarity, and subjected to 110 mm h−1 simulated rain until steady state infiltration. Image analysis was used to quantify crust morphology, porosity and characteristics of the seal and the unsealed soil below it. A conspicuous feature was a structural crust at the surface with a continuous dense layer of lesser porosity and smaller pores than uncrusted soil. The seal showed no evidence of a “washed-in” zone of illuvial clay in the control treatment, although dispersed clay was observed in the percolating water for some soils. Where FBCBA was effective in increasing water infiltration, an increase in total porosity attributed to planar pores was observed. A sandy loam Oxisol was the least prone to sealing. For this soil, a considerable amount of dispersed clay was observed in the control, while FBCBA rapidly flocculated clay and formed an illuvial clay layer, lowering infiltration. A layer of eluvial silt and fine sand was observed at the surface of soils where considerable dispersion occurred on non-treated soils. Differences in steady-state infiltration could not be explained by the variation in total porosity or pore shape. Spatial variability, pore continuity, and expansion/contraction of clays obscure any relationship with an averaged infiltration even on a small plot.  相似文献   
3.
There is increasing worldwide interest in land-use allocation and management within the sphere of rural planning and development. The study of land-use patterns mainly focuses on understanding the practices and values of individuals involved, and no debate of this issue would be complete without taking into account non-industrial private forest (NIPF) ownership as a key component in most rural areas worldwide. This paper empirically explores and assesses NIPF owners' management in terms of analysing dynamics in farming and forestry practices (past conversions from forestland to meadow and from marginal meadow to woodland, and intentions to change the current productive forest species and to extend the area of woodland) and landholding attributes (size and degree of parcellation in productive forestland). Logistic regression models were also used to investigate the probabilities and influencing factors involved in transforming marginal meadows to woodland, and attempts on the part of NIPF owners to change the current productive forest species and increase productive forestland. For this, a total of 103 NIPF owners in Northern Spain were interviewed in person, in March 2004, about their commitment to and involvement in land management during 1999–2003. The models correctly explained 73.3%, 83.7% and 73.3% of the variability in having converted marginal meadow in woodland and of future intentions to change the productive forest species and increase the area of productive forestland, respectively. The results of the study indicate that forest management mainly responds to investment and increasing the productivity of the land as a capital asset, which is directly influenced by the size and degree of parcellation of the holding, and directly or indirectly related to the owner's interest in timber production. The results may be used by forest professionals, researchers and policymakers in order to design and execute successful forest policies related to land management and planning.  相似文献   
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Yang  Shilei  Hao  Qian  Wang  Hailong  Van Zwieten  Lukas  Yu  Changxun  Liu  Taoze  Yang  Xiaomin  Zhang  Xiaodong  Song  Zhaoliang 《Journal of Soils and Sediments》2020,20(4):1811-1823
Journal of Soils and Sediments - Phytolith-occluded carbon (PhytOC) is mainly derived from the products of photosynthesis, which can be preserved in soils and sediments for hundreds-to-thousands of...  相似文献   
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Effects of the opiate agonist, morphine, and antagonist, naloxone, on LH release, courtship behavior and ejaculation frequency of mature, sexually active or sexually inactive rams were investigated. Plasma LH concentrations were monitored from blood samples collected every 15 min for 10 hr (0800 to 1800 hr) from eight rams that were isolated from or in contact with estrous females. Plasma LH concentration was higher (P<.05) in sexually active rams exposed to receptive females compared with hormone concentration of rams isolated from ewes. Intravenous infusion of morphine sulphate (1 mg/kg) into rams 4 and 6 hr after exposure to ewes reduced (P<.05) plasma LH concentration as compared to rams given saline. Morphine did not affect (P>.05) courtship behavior (investigatory sniff, mount attempt, foreleg kick, flehmen, vocalization) but diminished (P<.05) number of ejaculations. In another trial, LH concentrations were higher (P<.05) in seven sexually active rams given naloxone iv or when given to three rams through an intracerebroventricular cannula (icv) as compared to LH response of sexually inactive rams. LH did not differ (P>.05) in seven sexually inactive rams before or after administration of naloxone. Investigatory sniffs by sexually active rams were increased (P<.03) after treatment with the opiate antagonist. Four of the seven sexually active rams had more ejaculations after naloxone compared with the pretreatment period, but mean ejaculation frequency after treatment did not differ (P=.31). Naloxone did not stimulate courtship behavior of sexually inactive males. These data suggest that the effect of opiates on sexual behavior and LH secretion depends upon the inherent level of sexual activity among rams.  相似文献   
7.
通过对贵阳市固体废物的来源、分类及其双重特性进行分析,简要地介绍了固体废物的处理方法,并结合贵阳市固体废物的成分和特点,提出了供选择的最适宜的处理方法进行综合处理。  相似文献   
8.
为了挖掘与萝卜表型性状显著相关的分子标记,对60份萝卜的14个表型数据进行鉴定,筛选出具有多态性的分子标记29个(其中12个SNP标记和17个InDel标记)进行遗传多样性分析,并利用TASSEL5.0软件的广义线性模型(general linear mode, GLM)对萝卜的14个表型数据进行关联分析。研究结果表明,29个分子标记的等位基因(Na)数范围在2~3个,平均为2.14个;主等位基因频率(MAF)为0.53~0.94个,平均为0.68个;每个标记的期望杂合度(He)范围为0.12~0.93,平均为0.63。每个位点的多态性信息含量(PIC)值范围在0.11~0.37,平均为0.32;在12个表型性状中关联到17个显著相关的分子标记位点(其中7个SNP标记和10个InDel标记)(P≤0.01),贡献率在7.24%~23.25%。  相似文献   
9.
采用AMMI模型评价了烤烟品种(系)烟碱、总糖、还原糖、总氮、钾、氯、蛋白质等7种内在化学成分的稳定性,并对各品种的稳定性大小进行了排序。结果表明:(1)除还原糖外,不同品种的化学成分均存在着极显著的环境效应;除总糖、还原糖和总氮外,其余化学成分也存在着显著的基因型效应。(2)钾存在着显著的基因型×环境互作效应。钾含量稳定性较好的品种(系)有遵烟6号、GS518和K326。  相似文献   
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