浅谈无公害蔬菜生产中农药的科学使用

蔬菜是人们生活中必不可少的,发展安全、优质营养的无公害蔬菜是我国蔬菜发展的方向。文章对无公害蔬菜生产及病虫害防治过程中,如何科学、合理、有效地使用农药进行了阐述。     

我国蔬菜硝酸盐污染现状及防治研究

近年来硝酸盐与亚硝酸盐的污染问题引起了越来越多的关注与讨论,已成为研究的热点.蔬菜是硝酸盐易富集的农作物,特别是喜氮的叶菜类蔬菜.当前国际市场上对优质无污染蔬菜大量需求,我国各地正在抓紧发展蔬菜产业,尤其是优质无公害的蔬菜生产,进一步深入研究蔬菜中硝酸盐的污染及防治是十分迫切和必要的.     

蔬菜病虫害无公害防治技术

蔬菜是人们一日三餐所必需的食品，其产品质量直接影响着人们的生活质量。随着人们健康意识的增强，不但要求蔬菜具有食用价值，而且要安全、无污染、无公害，因此，生产优质、无公害蔬菜就成为蔬菜生产的必然趋势和发展方向。病虫害防治是无公害蔬菜生产的关键技术，无公害蔬菜病虫害防治应以农业防治为主，协调采用生物防治和物理防治，化学防治为辅，实行综合防治，蔬菜生产才能达到优质、高产、高效、无害的目的。     

关于永昌县发展优质无公害蔬菜适宜性的调查报告

随着我省蔬菜生产的快速发展和人民生活水平的日益提高 ,蔬菜产品的有害物质残留污染问题已越来越成为人们倍加关心的突出问题。而在现阶段生物类农药、生物类化肥还远远未成为生产主要施用各类的情况下 ,进行高标准的、优质无公害蔬菜生产确有相当难度 ,尤其在那些对化学农药、化学肥料依赖性大的地区 ,难度就显得更大些。此外 ,也还须考虑土壤、水质、大气等方面的有无污染源问题。分析认为 ,当前我省发展优质无公害蔬菜生产的适宜区域 ,应首选河西地区的沿祁连山冷凉灌区 ,而最佳适宜区当是此区内的半农半牧区。基于上述考虑与设想 ,我们选择了具有典型代表性的永昌县 ,并于近期内进行了专题性的实地考察。考察结果证实 ,永昌县确实有进行高标准、优质无公害蔬菜生产的优势条件和发展潜力 ;如能率先把永昌县建成高标准的优质无公害蔬菜生产示范基地 ,将会发挥良好的示范带动作用 ,使河西地区、乃至我省的蔬菜生产步入优质无公害这样一个新的层次和新的阶段。现就考察情况报告如下。1　永昌县的农业及蔬菜生产概况　永昌县是历史上的农业大县、粮油大县。在我省农业发展中 ,永昌县曾为中东部的粮食短缺作出过重大的贡献。 1998年粮食价格放开之前 ,全县平均每...     

无公害蔬菜生产施肥技术

无公害蔬菜是指产地生态环境清洁，按照特定的技术操作规程进行生产，将有害物质含量控制在规定标准内，并由授权部门审定批准．允许使用无公害农产品标志的安全、优质、营养型蔬菜。生产无公害蔬菜，不仅可以有效地保护农业生态环境，合理利用资源，取得较好的社会效益和生态效益，而且能获得比普通蔬菜高的经济效益。尤其是我国加入WTO以后以及随着人民生活水平的提高，消费者的质量安全意识增强．对洁净蔬菜、无公害蔬菜、绿色蔬菜等都有强烈的消费需求。因此，生产无公害蔬菜，满足市场需求，保障人体健康，促进经济外向型发展，是蔬菜生产的发展方向。     

无公害蔬菜病害综合防治技术

无公害蔬菜是指蔬菜中的农药残留、重金属、硝酸盐等各种污染有害物质的含量，控制在国家规定的范围内，人们食用后不足以对人体造成危害的蔬菜。目前无公害蔬菜生产中病害的防治主要遵循以农业综合防治为主的原则，即积极推广生物防治技术、减少化学农药用量、合理使用高效低毒化学农药、合理施用化学肥料和有机肥料等，从而创造一个有利于蔬菜生长而不利于病害繁衍扩展的生态环境，以减轻或控制其危害，达到高产、高效、优质的栽培目的。无公害蔬菜病害综合防治技术主要有     

无公害大蒜施肥与用药技术规范

无公害蔬菜是无公害食品的一类,是指安全、优质、营养类蔬菜的统称。近年来,食品安全问题频出,严重威胁着人们的身体健康和生命安全。蔬菜作为人们每天必备的食品,无害化生产更应引起关注,而怎样进行无害化生产有必要再次成为家喻户晓的基本技能,特撰写此文。     

生产无公害蔬菜要注意合理施肥

如何生产高产优质的无公害蔬菜,保持农业的可持续发展已迫在眉睫,本文就生产无公害蔬菜的关键措施———如何正确选择与合理施用肥料做一简单介绍。     

谈无公害蔬菜生产中农药的科学使用

无公害蔬菜发展速度是比较快的。然而,无公害蔬菜的发展也有很多困难,从而使无公害蔬菜在品质、数量等方面很难满足人们的消费需求。那么在蔬菜生产过程中科学正确的使用农药,有效地防止病虫害,提高产品经济效益,成为蔬菜生产过程中非常突出的问题。     

“硬”、“软”一起抓,建设现代环保乡镇——鹤山市共和镇城镇化技术集成应用综述

共和镇地势平坦,土地肥沃,是鹤山市第二"粮仓"和"三高"农业生产基地.共和镇还是江门鹤山市现代农业示范区和传统的优质蔬菜种植基地,获得了广东省无公害蔬菜标志认证."共裕"牌粉葛获国家绿色食品认证,"三瓜两豆"远近驰名.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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-