构建国家绿色肥料体系

正欧美国家在20世纪90年代以前,依靠施用化肥在保障粮食增产的同时,化肥使用对环境带来了严重的负面影响。之后,通过发展高效肥料品种、推广精准施肥技术以及施肥管理法制化等系列措施,美国在实现化肥零增长、欧盟化肥用量持续下降的情况下,粮食产量持续提高,作物高产和环境保护协调发展,化肥施用的环境问题得到有效解决。我国从20世纪80年代开始大量施用化肥,目前农业年化肥消费量(折纯)达到了6 000万t,占世界化肥消     

信息动态

欧美国家在20世纪90年代以前,依靠施用化肥在保障粮食增产的同时,化肥使用对环境带来了严重的负面影响.之后,通过发展高效肥料品种、推广精准施肥技术以及施肥管理法制化等系列措施,美国在实现化肥零增长、欧盟化肥用量持续下降的情况下,粮食产量持续提高,作物高产和环境保护协调发展,化肥施用的环境问题得到有效解决.     

一种新型环保的控缓释肥料在天津市研制成功

一种利用废旧塑料进行肥料包衣,大幅度降低控释肥料成本,可用于大田作物的新型环保肥料,近日在天津研制成功。近年来,由于化肥用量增长过快,肥料应用及其它相关技术研究滞后,化肥施用不合理,导致化肥利     

科技简讯

科技简讯生物活性磷钾复合肥１概述肥料是提高农作物产量的重要条件。据联合国粮农组织的统计，粮食增产约５０％是增施化肥的结果。但是，近年来我国各地连年施用化肥，土壤中有机质含量下降，增产效果已不明显，有的地方甚至产量下降。这是由于滥用或超量施用化肥，使土...     

大力发展有机肥、有机无机复合（混）肥

农业上大量施用无机化肥,在获得农作物高产同时,也带来了作物品质下降和环境污染加重的负面影响,其原因主要是,有机肥用量不足,甚至不使用有机肥。为此,应大力倡导和推广无机化肥与有机肥配合使用经验,扬长避短,发挥协同效应,以取得作物优质高产、减少环境污染的良好效果,并对如何提高该肥料产品质量,提出了措施意见。     

生物有机肥及其应用前景

当前农业生产中应用的肥料品种很多,其中生物有机肥为广大绿色食品生产者青睐。2002年,国家科技部“863”计划现代企业领域中将“新型多功能肥料研究与开发”列为一个研究项目。可见,国家科技主管部门对生物有机肥的重视。近年来,人们环境保护意识增强,开始认真考虑减少化肥的用量,发展有机农业,建立绿色食品安全工程体系。施用有机肥是中国农业生产的传统经验,直到20世纪50～60年代,我国肥料资源绝大部分仍然依靠有机肥料。60年代以后,特别是农村实行承包责任制以后,化肥用量迅速增加,有机肥的比重才有所下降,但从养分含量计,仍占我国…     

论化肥的后效

对当季作物施用的肥料,其残留在土壤的部分在后续作物上发挥的肥效,称肥料的后效或残效。年复一年的对土壤施肥,其后效将持续积累。化肥是我国现代农业用肥的主体,其当季肥效和后效的积累,是我国土壤有效肥力不断提高和农作物持续增产的重要因素。认识化肥的后效对全面评价和充分发挥化肥的积极作用,减少其负面影响具有重要意义。     

发展作物专用肥 推进我国平衡施肥

近年来,我国农业出现化肥用量大幅度增加、但肥料利用率及肥料效应却大幅度下降的问题。究其原因,主要是化肥结构中氮磷钾比例不合理、钾素长期严重亏缺、土壤供钾能力下降且其它养分障碍因子增多以及施肥缺乏科学性。针对我国农业劳动者专业素质低等现状,必须迅速发展作物专用肥料以简化平衡施肥技术,使之大范围推广应用。然而,作物专用肥料的健康发展还有赖于化肥结构的宏观调整、平衡施肥技术研究、化肥生产工艺、肥料市场规范和农化服务等多方面的不断发展与完善。     

化肥施用与土壤环境安全效应的研究

介绍我国肥料使用现状,分析化肥施用对土壤、环境的影响,并提出了提高化肥施用安全的若干建议。     

氮磷化肥配合施用提高化肥经济效益

<正> 增施化肥是提高作物单位面积产量、改善农作物品质的一项重要措施。国家为了发展化肥工业,投入了巨大的工业投资,农民为了增施化肥用量,支付了较大的化肥费用。施肥经济效益大小,不仅关系到化肥工业的投资效果,也关系到农民的经济收益。近十多年来,随着化肥工业的迅速发展,化肥用量也相应增加,对农业生产起了很大的作用。但是在施肥上存在很大有盲目性,北方普遍重氮轻磷,氮磷比例失调,氮肥的肥效较六十年代明显下降,出现增产不增收,甚至减产。因此,研究化肥的合理施用,对提高化肥经济效益,促进化肥工业和农业生产的发展,具有重要的现实意义。我们从1981—1986年在临潼县灌区二种主要土壤((土娄)上、黄墡土)、三种作物(小麦、玉米、棉花)进行氮磷配合施用试验。通过     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.