安徽省肥东县土壤养分时间变化特征

文章研究了1982年第二次土壤普查与2012年测土配方施肥这30多年来安徽省肥东县土壤表层(0-20 cm)有机质、有效磷和速效钾的时间变化规律.通过分析得出,1982-2012年间有机质、有效磷、速效钾的均值等都呈现出增长的趋势,有机质增长了大约113%;有效磷增长了218%;速效钾增长了大约82%,当地农民在第二次土壤普查之后,加大了氮肥、磷肥的施用,而忽略了钾肥的施用,再加上土地利用方式及管理方式的改变,导致肥东县的土壤养分含量发生了较大变化.     

河南省土壤养分状况研究

利用测土配方施肥数据,对全省95个县40多万个土壤样品分析表明:全省土壤有机质、全氮含量平均为15.98和0.96 g/kg,土壤速效磷、速效钾、缓效钾平均分别为17.37,121.91,676.41 mg/kg,土壤有效铁、有效锰、有效铜、有效锌、水溶性硼平均含量分别为11.23,16.47,1.49,1.38,0.64 mg/kg.与第2次土壤普查相比,全省有机质、全氮、速效磷、有效铜、有效锌、水溶性硼含量分别增加30.98%,20%,194.36%,22.89%,107.74%,65.13%;土壤速效钾、有效锰、有效铁含量分别减少8.13%,3.37%,29.37%.从养分分级来看,全省有机质、全氮、速效磷、速效钾、有效硼、有效锌、有效铁、有效锰含量较低的样本占测试样本的比例分别为9.77%,2.98%,30.87%,40.18%,43.32%,11.56%,12.46%,6.24%.     

耿马县耕地土壤养分现状及施肥对策

在2006年测土配方施肥试点项目中,对耿马县耕地土壤养分进行了一次全面调查,其结果,与1984年土壤普查相比,耿马县耕地土壤养分除碱解氮大幅度增加外,土壤有机质,全氮速效磷,速效钾普遍下降。根据土壤养分现状和大量田间试验参数,提出了增施有机肥和磷钾肥,控制氮肥用量,补施微肥,积极推广测土配方施肥新技术等施肥对策。     

贵德县耕层土壤农化指标含量分析

采用常规方法,分析了贵德县174个耕层土壤8项农化指标,旨在为耕地地力评价和测土配方施肥提供基础数据。结果表明:贵德县耕层土壤平均pH 8.16,有机质24.24 g/kg,速效氮104 mg/kg,有效磷42 mg/kg,速效钾276 mg/kg,全氮1.26 g/kg,全磷1.75 g/kg,全钾19.70 g/kg;总体速效钾含量水平高;速效氮、有效磷、有机质含量与丰缺指标相比较基本为中等水平。     

玛纳斯县农田土壤养分变化分析

土壤性质的空间变异对于揭示各项养分的分布规律,实行特定的田间管理措施和实施精确农业有重要意义。文章对照分析了1982年和2012年玛纳斯县农田表层土壤有机质、碱解氮、有效磷、速效钾及 pH 的时空变化情况。结果发现30年来研究区土壤养分表现出一定的空间变异性,有机质、碱解氮、有效磷、速效钾含量及 pH 值变化明显,各项等级均有增长,其中有机质和有效磷的变异系数最为明显,玛纳斯县研究区域养分总体含量由20世纪80年代的“缺氮少磷富钾”变为目前的“平氮平磷富钾”。     

基于GIS地统计学的海坛岛农田养分变异研究

利用半变异方差函数的方法揭示海坛岛的农田土壤养分空间变异。结果表明:海坛岛土壤有机质、碱解氮、有效磷和速效钾平均含量分别为7.77g/kg、41.68mg/kg、27.57mg/kg和49.12mg/kg,各养分指标变异系数(CV)为中等变异水平。土壤养分由高到低可分为5级,有机质、碱解氮含量较低;有效磷十分丰富;速效钾含量极低。半变异方差函数显示有机质、碱解氮、有效磷和速效钾空间自相关性较低(块金效应都大于85%)。海坛岛土壤养分含量空间分布具有其特殊性,需要增加施肥指导,保持土地的可持续生产能力。     

内蒙古中部农牧交错带生态建设对浅层土壤养分的影响

以内蒙古化德县七号镇为例,分别于2000,2008和2013年,在典型地段的6种主要不同农业土地利用类型地块土壤浅层0～20 cm进行土壤样品采集.通过化验土壤养分含量,对比分析不同土地利用类型地块土壤养分含量的动态变化,探讨生态建设对土壤浅层养分的影响.结果表明：水浇地因定期施较多优质有机肥和磷肥,土壤养分含量相对稳定,其有机质、全氮、速效氮含量均有不同程度的变化,但变化水平不显著,速效磷含量上升,因隔年种植喜钾作物马铃薯,导致速效钾含量呈波动变化;旱滩地因有机肥施用严重不足,其有机质、全氮、速效氮含量下降;旱坡地因定期休耕压青,土壤养分得以维持;天然草地因退牧还草,其有机质、全氮、速效氮、速效磷、速效钾含量均增加;柠条林地、围栏草地因土地沙化严重,导致土壤养分变化不大;旱坡地、天然草地、柠条林地、围栏草地pH值稍有下降.牧草地通过自然修复,可有效提高土壤养分含量,耕地土壤养分含量由施肥和耕作方式决定.分析不同土地利用类型地块土壤养分含量的动态变化及其原因,提出合理利用土地资源、提高土壤养分的若干建议.     

南阳盆地施肥调查与土壤养分状况分析

用网格法结合村庄地块采集土壤样品,调查农民施肥状况.土样分析数据表明：南阳盆地土壤养分状况整体处于中等水平,土壤有机质、碱解氮、速效磷和速效钾平均质量比分别为14.63g/kg和68.62,16.20,76.26mg/kg,与第二次土壤普查结果相比有机质、土壤速效磷质量比分别提高了24.0%和200%,而土壤速效钾质量比下降了50.1%.调查资料表明：农民施肥存在肥料品种单一、施肥量、施肥方式等不合理问题,应重视有机肥施用,推广秸秆还田,采用复合和缓1控释氮肥及合理的施氮技术,注意减磷补钾.     

崇义县上堡梯田区土壤养分变异特征及等级评价

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。     

山东西部土壤耕层养分变化及持续利用对策

土壤养分对于农作物生长有着极其重要的作用.聊城市是重要的商品粮棉基地,开展该区土壤耕层养分状况和变化研究具有重要意义.经过土壤样品的采集、分析和统计并与第二次土壤普查结果比较,20年间聊城市土壤养分已发生较大变化,有机质、全氮、速效磷含量增加、变异系数亦增加;碱解氮含量增加、变异系数减小;速效钾含量减少、变异系数增加.其中速效磷含量增加明显,速效钾、速效磷变异系数增加明显.根据野外调查和统计资料分析了上述变化的原因、提出了相应的土壤资源持续利用措施,可望对研究区域农业生产提供帮助.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has