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1.
在河北唐山南堡开发区,结合穴状衬膜改土整地,移栽了绒毛白蜡、国槐、桧柏、柳树等研究用苗木,以土钻取土法进行两年土壤水盐动态定期监测,研究了移栽苗木对滨海盐渍土水盐动态规律的影响,以期为滨海泥质盐碱地造林绿化的树种选择提供理论依据。结果表明,与未移栽苗木的处理(对照组)相比,移栽苗木会降低土壤含水量和电导率,并增大二者的月际变化幅度,但对土壤含水量和电导率的总体变化趋势影响不大。苗木的生长季、树冠结构和根系吸水是移栽苗木后影响土壤水盐动态变化的主要因素,其中苗木的生长季影响主要表现为同一时期,各种苗木所在土壤含水量差异较大;苗木的冠型结构主要影响表层土的土壤含水量;根系吸水作用则是改变了土壤含水量和盐分的垂直分布。4种苗木间对比,土壤含水量动态变化无明显差异;土壤电导率动态变化呈显著差异,其中以桧柏对土壤电导率动态变化影响较为显著、脱盐降盐效果最好。  相似文献   

2.
【目的】掌握江苏北部滨海盐碱地土壤盐分特征及其与杨树生长的关系。【方法】分析江苏盐城市大丰区林场的35杨(Populus deltoides ‘I-35’)林地、农耕地以及未开垦的盐碱地土壤盐分状况,并对杨树胸径、树高和成活率进行了调查。【结果】不同类型的土壤含盐量差异较大,农耕地土壤含盐量(质量分数)普遍低于0.1%;杨树林地土壤含盐量多数低于0.2%;未开垦的盐碱地土壤含盐量明显较高;含盐量较高的土壤盐分具有明显的表聚特征;土壤pH普遍为8~9,平均为8.23,属于碱性土壤;土壤含盐量、电导率和pH三者之间存在显著的正相关关系,其中土壤含盐量与电导率之间用二次多项式方程拟合的效果最好;土壤含盐量与pH之间、土壤电导率与pH之间均是指数方程的拟合效果最好;土壤含盐量与杨树的成活率、胸径、树高之间均呈显著的负相关,相互之间的关系可以用指数方程或乘幂方程拟合。【结论】不同利用类型的土壤含盐量及其盐分特征存在较大差异;土壤含盐量对杨树的生长和成活率影响较大,当土壤含盐量高于0.3%时,杨树的胸径和树高生长以及成活率均明显较低;当土壤含盐量低于0.2%时,杨树的胸径和树高生长以及成活率均比较正常。  相似文献   

3.
在鲁中南低山丘陵区选择青石山和砂石山设立两处试验地、4个区组,开展了侧柏、黑松等8个树种贫瘠荒山直播造林技术研究,结果表明:供试树种均能用于荒山大面积直播造林,提前整地和施用土壤保水剂都能显著地提高直播造林的出苗率、保存率和苗木生长量,研究了两种立地条件下侧柏、刺槐直播造林土壤保水剂最佳施用剂量,覆草和间苗定苗亦能明显提高直播造林的出苗率和苗木生长量.  相似文献   

4.
不同地表覆盖方式对土壤水分、温度及幼苗生长的影响   总被引:7,自引:0,他引:7  
采用温室盆栽实验与人工造林地表覆盖试验方法,研究不同覆盖材料下的土壤蒸发特性、土壤保墒能力及苗木生长状况。结果表明:在土表覆盖条件下土壤含水量较对照(CK)有不同程度提高;在水稻秸秆覆盖下冰脆李、栾树林地土壤含水量较对照(CK)分别增加13.86%和9.82%;在玉米秸秆覆盖条件下梓树林地土壤含水量较对照(CK)增加7.79%;土表覆盖措施对苗木根质量和叶面积影响显著而对苗高影响不显著。喀斯特地区人工造林采用地表覆盖措施可减轻高温对苗木的伤害及季节性干旱对幼林生长的影响,从而提高苗木生物量。因此,地表覆盖可作为喀斯特地区人工造林初期促进植被恢复的有效措施之一。  相似文献   

5.
印楝1年生苗木生长节律与数量分级标准   总被引:2,自引:0,他引:2  
通过对1年生印楝实生苗木群体的动态研究,建立了苗木的年生长模型、连日生长量模型和日平均生长量模型,并据此模型将印楝苗木生长节律划分为4个阶段:出苗期(10月中旬至下旬)、生长初期(11月上旬至翌年4月中旬)、速生期(4月下旬至9月下旬)和生长后期(10月上旬至下旬);苗木生物量积累与苗高、地径的函数模型关系表明,苗木生物量(包括地上部分、地下部分和全株干重)与苗高、地径的相关性极为密切,其中全株干重占全株鲜重的38.8%,地上部分干重占全株鲜重的26.8%,占全株干重的69.1%;同时,以苗高、地径为参考指标,对9个月生的印楝造林苗木进行了数量分级标准划分,并运用该分级标准进行造林试验,结果表明将印楝造林苗木从数量指标上划分为Ⅰ级、Ⅱ级和Ⅲ级是科学合理并切实可行的,其中仅Ⅰ级与Ⅱ级可以用作造林合格苗木.  相似文献   

6.
盐碱土是含有过量水溶性盐分的土壤。依据呈现碱性反应的高低又分为碱土与盐土。盐土呈微碱性反应,多发生在滨海盐碱地区,天津地区土壤尤为代表。盐碱地影响植被正常生长,制约农作物的产量,约束植被、作物的适种性和品质,影响林业与畜牧业甚至整个环境质量,从而抑制人类的生活与发展。通过分析盐碱地对植物产生的危害,论述盐碱地传统改良措施与生态修复方法的优缺点,比选今后盐碱地修复改良的方向,以更好的利用与发挥盐碱地的作用。  相似文献   

7.
近年来,北安市在三北防护林和退耕还林造林中,用杨大苗造林面积较多,约占平原造林的80%左右,如何提高杨大苗的造林成活率显得尤为重要,根据本人多年来对杨木苗造林的经验,总结出提高杨大苗造林成活率的几种方法,供广大同行参考:1秋季造林整地挖明穴,规格50cm×50cm,每年春季造林的前一年秋季进行整。有以下几个优点:可以提前造林时间,北安地区在4月10日以后即可造林,达到顶凌造林的目的;保持土壤墒情,冬天穴内聚积的冰雪融化后可以起到保墒作用。2选苗选择三根两干或两根一干,无病虫害,无机械损伤,木质化好,根系发达的苗木。3苗木处理3.1将…  相似文献   

8.
根据盐碱地的产生原因,通过结合盐碱地治理生物措施、物理措施、化学措施、水利工程措施来进行综合治理,本研究结合隔盐阻盐材料、有机改良剂和耐盐苗木,提出一种盐碱地改良技术模式。模式主要包括碎石淋洗+暗管排盐、隔盐阻盐、土壤有机改良、栽植苗木、抚育管理等五项工序。本次研究以沧州渤海湾新区盐碱地为研究对象,通过对不同工序组合来探究适宜渤海湾泥质盐碱地的绿化技术模式。在本次改良渤海湾土壤研究中,优先选择"暗管排盐+木炭隔盐阻盐层+有机液体改良剂(竹醋液稀释150倍)+国槐"改良技术模式。  相似文献   

9.
生物有机肥对盐渍土壤水盐动态及番茄产量的影响   总被引:3,自引:0,他引:3  
为探讨生物有机肥对不同类型盐渍土壤(设施次生盐渍土、滨海盐渍土)水盐动态和作物产量的影响,采用盆栽试验方法研究不同施肥(不施肥、化肥、生物有机肥、生物有机肥+化肥(比例为1∶1))处理对盐渍土土壤含水率、电导率、盐分离子组成变化和番茄产量、水分利用效率的影响。结果表明:(a)单施生物有机肥处理和生物有机肥+化肥处理均可以提高土壤含水率;(b)单施生物有机肥处理的土壤电导率最低,其次为生物有机肥+化肥处理;(c)对于设施次生盐渍土,与化肥处理相比,单施生物有机肥处理和生物有机肥+化肥处理的土壤盐分离子总量分别降低了23.63%和15.60%;(d)对于滨海盐渍土,与化肥处理相比,单施生物有机肥处理和生物有机肥+化肥处理的土壤盐分离子总量分别降低了22.34%和10.32%;(e)番茄收获后,设施次生盐渍土各处理的NO_3~-和SO_4~(2-)在土壤盐分中的占比降低,滨海盐渍土各处理的Na~+、K~+和Cl~-占比降低;(f)单施生物有机肥处理最有利于土壤微生物的增加,其次是生物有机肥+化肥处理;设施次生盐渍土中生物有机肥+化肥处理的番茄产量最高,比单施生物有机肥处理增产165.5%;(g)施用生物有机肥可以提高设施次生盐渍土的作物产量和灌溉水利用效率,而单施化肥则可能会造成作物绝产;(h)施用化肥虽然提高滨海盐渍土的作物产量,但施用生物有机肥处理的灌溉水利用效率相对较高。  相似文献   

10.
东营市有2/3的土地是盐碱地,土壤类型为滨海盐碱土和潮土。土壤的盐碱对植物的生长及发育造成严重的影响,造成植株生长势比较弱,种子发育不良,不能形成生理成熟的种子或不结种子,阻碍了现有园林植物的推广应用。扦插育出的苗木具有适应性强、保持亲本性状,育苗周期短,材料来源丰富  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

17.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

18.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

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