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1.
针对燕山山麓高产粮区特殊的生态条件及生产中存在的问题 ,1996~ 1999年在河北省遵化市团瓢庄乡进行了冬小麦—夏玉米轮作条件下土壤养分限制因子与排列序谱及高产、高效施肥指标的试验。结果表明 ,在燕山山麓冬小麦—夏玉米轮作条件下 ,冬小麦的养分因子排序为 :N >P >K >S >Mn >Cu >B >Zn ,限制因子为N、P、K、S ,而Zn、Mn、B、Cu则为非限制因子。夏玉米的养分因子排序为 :N >K >P >Zn >Mn >Cu>B >S ,限制因子是N、K、P、Zn、Mn ,非限制因子是S和B。最佳效益施肥量为 :N 45 0kg hm2 ;P2 O5 90~ 12 0kg hm2 ;K2 O 15 0kg hm2 。  相似文献   

2.
1996~1998年在河北省滦县试区进行冬小麦土壤养分限制因子与高产高效施肥指标试验。结果表明,在滦河三角洲沙区,氮、钾是冬小麦产量的土壤养分限制因子,限制因子对冬小麦产量的效应N>K2O。效益最佳平台区施肥量单施化肥时,N用量为293.40~312.75kg/hm2,K2O为170.70~178.95kg/hm2;施用有机肥30t/hm2时,N用量为297.60~313.65kg/hm2,K2O为151.50~159.15kg/hm2。  相似文献   

3.
10月10日,由河北省科委组织有关专家对我院和遵化市农业局共同承担的河北省科委下达的“燕山山麓平原粮经牧协调发展持续高效配套技术研究”(课题编号:96220916D)的子课题“高产粮区主要作物主要养分限制因子和提高肥料利用率的研究”进行了技术鉴定。鉴定专家一致认为该项研究具有以下创新点:1.系统研究了燕山山麓平原区高产粮区冬小麦—夏玉米长期轮作条件下持续高产的养分限制因子,明确了养分限制因子谱序,并在此基础上提出了施肥技术方案。2.探明了土壤中大量元素和微量元素周年在0~120cm土体内的迁移规…  相似文献   

4.
高速公路边坡不同恢复年限土壤性质及生态防护模式研究   总被引:1,自引:0,他引:1  
以陕南土石山区不同植被恢复年限高速公路为研究对象,综合分析了不同护坡模式的防护效果及不同坡向间土壤理化性质的差异性。结果表明:①土石山区高速公路边坡土壤养分条件受恢复年限的影响显著。土壤有机质、全N含量处于缺乏和显著缺乏水平;随着边坡植被恢复年限延长及植被的演替进程推移,植被长势渐好,豆科植物的固氮作用使得土壤有机质和全N含量增加,但仍处于较低水平;②有机质、全N、速效K、含水率排序均为骨架护坡挂网喷播拱形+植生袋,且养分表现出向表层富集的趋势,骨架护坡保水保肥效果较好,该护坡模式为最优选择;③土壤有机质、全N、速效P、速效K、含水率、孔隙度等均表现为阴坡阳坡;④土壤的养分(有机质、全N、速效P)已成为边坡植被恢复和演替的限制因子,应适当采取土壤改良措施,为植被恢复创造良好的环境,促进植物生长,使其尽快发挥其水土保持效果。  相似文献   

5.
本研究利用杂交玉米种SC704和石单早为试材,于不同生育期对玉米根系的干物重和养分状况进行了测定分析。试验结果表明,随着玉米生长发育进程的推移,单株根重呈单峰曲线变化,于吐丝期(SC704)至乳熟末期(石单早)达最大值;根系N、P、K养分的百分含量则逐渐降低;可溶性糖含量呈波动性变化,于拔节前和吐丝期出现两个峰值;游离氨基酸含量表现为未入土气生根>已入土并长出侧根的气生根>地表下30—50cm深层的根样,且三者在成熟期均大于吐丝期;此外,本文还测算了玉米根系对土壤养分的归还量。  相似文献   

6.
通过对贵阳二环林带不同林分类型下森林土壤肥力的研究,结果表明:林带内绝大多数林地土壤的pH值低于7,不同林分类型下的土壤肥力存在较大差异,林地土壤表层供P、K水平极低,一些土壤严重缺K,供N水平中等;土壤速效养分含量呈现较明显的垂直分布规律,总的趋势是上部土层主要养分含量高于下部土层,0~20 cm土层N含量比20~40 cm平均分别高出4.7和5.2倍,K含量平均分别高出26.8%和28.0%.林木施肥时,应首先给土壤补充P和K,其次是N,磷肥应尽可能深施,以提高下部土层P素肥力,以促进植物根系的正常生长和对养分的吸收.  相似文献   

7.
基于上堡梯田区内472件土壤样中N、P、K_2O、碱解氮(JJN)、有效磷(YXP)、速效钾(SXK)、有机质(Corg)和pH的分析测试结果,采用地质统计分析法和GIS技术相结合研究养分空间变异特征,依据行业现行规范标准评价养分等级,为研究区内养分管理、精准施肥提供依据。上堡梯田区内土壤养分中N、P、K平均值均高于赣州市和全国土壤的背景值。N、P、K、有机质、碱解氮和pH为中等变异,速效钾和有效磷均为强变异水平,N、P、有机质、碱解氮、有效磷和pH的半差函数模型均为指数模型,K、速效钾型为球状模型,具有较强的空间相关性;土壤养分地球化学等级主要为中等以上;土壤有机质与N、P、K、碱解氮、有效磷碱和速效钾存在极显著相关性,土壤pH与N、P、K、碱解氮、有效磷存在极显著相关性。  相似文献   

8.
通过对大理洱海湖滨区菜园土具有代表性的98个土壤样品的pH值及其他养分含量进行测定分析。结果表明,菜园土pH值与土壤有机质,全N无明显相关性。而与土壤速效N,速效P呈显著相关。土壤有效Cu、Zn、Fe、Mn与pH值无明显相关性,速效B和pH值的相关性较显著,土壤有机质,N、P含量较高,而K不足,有效Mn、B含量较低。  相似文献   

9.
以成年兴津温州蜜柑、尤力克柠檬和圆金柑为材料,研究落蕾、落花和脱落幼果的养分含量及脱落损耗.结果表明:3个品种的落蕾和落花营养元素含量为N 2.53%~3.43%,P 0.23%~0.30%,K 1.58%~2.25%,Ca、Mg和S含量为0.15%~0.75%,Fe、Mn、Zn、Cu和B含量为9.6~66.6mg/kg.除落花的B含量显著高于落蕾外,落花和落蕾的多数营养元素含量相近,且品种间差异小.与蕾和花相比,兴津温州蜜柑落果的N和P含量出现较大幅度下降,平均下降幅度分别达10.29%和13.85%,Fe含量上升,其它营养元素含量变化不明显;圆金柑脱落幼果所有元素含量及尤力克柠檬脱落幼果N、K和Cu以外其余元素含量均有不同程度的上升,且均达到显著差异(p<0.05).兴津温州蜜柑、尤力克柠檬和圆金柑单株脱落的蕾、花和幼果总干质量分别为3 533.6g、394.3g和122.9g,由此所造成的单株主要养分损耗兴津温州蜜柑为N 119.4g、P 10.1g、K 76.2g、M g 7.1g、Zn 81.5mg和B 170.2mg,尤力克柠檬和圆金柑分别为N 10.2g和4.1g、P 1.0g和0.4g、K 7.0g和2.4g、Mg 0.7g和0.3g、Zn 7.6mg和2.7mg和B 18.64mg和4.0mg.兴津温州蜜柑的养分损耗落花>落蕾>落果,尤力克柠檬为落果>落花>落蕾,圆金柑为落花>落果>落蕾.品种间以兴津温州蜜柑脱落的养分损耗最大,尤力克柠檬其次,圆金柑最小.因此,柑橘多花品种应控制过量开花.  相似文献   

10.
为解决农田节水问题,进行了田间水热通量观测和水热耦合循环过程机理分析。观测系统主要包括:常规气象、辐射、涡度相关法观测系统以及土壤水分观测剖面。该系统能够连续和稳定地观测土壤-植物-大气连续体中的水热循环过程,涡度相关法观测数据具有与国际同类观测一致的精度。对2005年山东省位山引黄灌区冬小麦和夏玉米生长期内水热平衡的分析表明:当叶面积指数较大时潜热是农田能量消耗的主要方式;在冬小麦返青至收割期内作物耗水略小于供水,而在玉米生长期内供水远大于作物耗水,灌区供水充分。  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.
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   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
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   

15.
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   

16.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

17.
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   

18.
19.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

20.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

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