Einfluß der N-Düngung auf Ertragsentwicklung landwirtschaftlicher Kulturen und Veränderung des mineralischen N-Gehaltes im Boden bei achtjährigen Dauerversuchen

Influence of long-time Nitrogen-fertilizing on yield response of agricultural crops and mineralized Nitrogen in soil
In the years 1979–1986 a fertilizer trial with increasing Nitrogen amount was performed in order to prove the N_min-method according to S charpf and W ehrmann . The N_min-method regards the mineralized N in soil (N_min) for optimizing the N-fertilizer amount at the begin of vegetation, could be confirmed. The optimal N-rate (including N_min) was for winter wheat and winter barley 120 kg/ha, winter rye 100 kg/ha and sugar beet 200 kg/ha. For cereals additional N-rates were given at the end of tillering 20 kg/ha N and at ear emergency 60 kg/ha N. For the optimal N-fertilizing system we found a positive N-balance (input-output) in a range of 10–25 kg/ha. The influence of N-fertilizing on the mineralized N-amount in soil was very small comparing to influence of weather, soil type or crops. Only at one location a little increase of N_min (10–15 kg/ha) could be observed after a positive N-balance (50 kg/ha).     

关于深化水土保持科研机构改革的思考

为适应社会主义市场经济发展的要求,当前水土保持科研机构的主业,一是搞好水保科学研究,二是创办经济实体,搞好开发创收。科研项目的选择,除国家水土保持科研机构适当选上少量基础理论研究项目外,地方水保科研机构一律选上应用科研项目和示范推广项目。为稳定水保持科技队伍,应积极创办经济实体,利用技术人才优势,实行技术有偿服务。     

土壤管理对枇杷生长的影响

通过土壤管理试验,提出了适宜安康丘陵山地栽培枇杷的土壤型类型和施肥种类、配比方法及管理技术。     

不同施肥方法对地膜覆盖栽培番茄生长和产量的效应

3年分别在地膜覆盖栽培番茄定植缓苗后、门果膨大期、盛花期叶面喷施3次纳米肥精600倍液、700倍液、绿丰霖2000倍液、500倍磷酸二氢钾,均能极显著比常规破膜施肥降低膜内杂草滋生和管理成本,提高覆膜效应,提高番茄株高、茎粗和产量,以叶面喷施纳米肥精600倍液和绿丰霖2000倍液较明显,生产上应积极推广.     

Ecdysteroid receptor docking suggests that dibenzoylhydrazine-based insecticides are devoid of any deleterious effect on the parasitic wasp Psyttalia concolor (Hym. Braconidae)

BACKGROUND: The moulting accelerating compounds (MACs) or ecdysteroid agonists represent a selective group of insecticides acting upon binding to the ecdysteroid receptor (EcR) and leading to lethal premature moulting in larval stages and aborted reproduction in adults. Psyttalia concolor Szèpl. is a useful parasitic wasp attacking important tephritid pests such as the medfly and olive fruit fly. RESULTS: Contact and oral exposure in the laboratory of female parasitic wasps to the dibenzoylhydrazine‐based methoxyfenozide, tebufenozide and RH‐5849 did not provoke negative effects. No mortality and no reduction in beneficial capacity were observed. The ligand‐binding domain (LBD) of the EcR of P. concolor was sequenced, and a homology protein model was constructed which confirmed a cavity structure with 12 α‐helices, harbouring the natural insect moulting hormone 20‐hydroxyecdysone. However, a steric clash occurred for the MAC insecticides owing to a restricted extent of the ligand‐binding cavity of the PcLBD‐EcR, while they did dock well in that of susceptible insects. CONCLUSIONS: The insect toxicity assays demonstrated that MACs are selective for P. concolor. The modelling/docking experiments are indications that these insecticides do not bind with the LBD‐EcR of P. concolor and support the theory that they show no biological effects in the parasitic wasp. These data may help in explaining the compatible use of MACs together with parasitic wasps in IPM programmes. Copyright © 2012 Society of Chemical Industry     

雷公藤多苷药效机理及安全性研究概况

雷公藤多苷具有抗炎、免疫调节及抗生育等作用,该文概述了雷公藤多苷的临床应用及其作用机理,同时总结归纳了其毒副作用和不良反应,为更安全和广泛的应用雷公藤多苷提供了理论和试验依据。     

余姚农村水环境存在的问题及治理对策

针对农村水环境水土流失、水生态环境恶化、面源污染严重等现状,提出发展农村污水无害化资源化技术,加强生态农业和生态水利建设,改革农业运作方式,加强人工及自然生物处理技术研究等水污染治理对策。在此基础上呼吁各级政府重视农村水污染的治理,积极改善农村的水环境。     

东北春玉米连作体系土壤剖面无机氮的变化特征

【目的】研究不同施肥方式对东北春玉米生长及连作体系土壤中氮素含量的影响,为春玉米的合理施肥提供理论依据。【方法】2005-2006年,在东北中部黑土春玉米连作区进行2年的田间定点试验,研究了一次性施肥（农民习惯施肥1、农民习惯施肥2）和推荐施肥条件下,玉米不同生育阶段地上部生物量和吸氮量及土壤无机氮含量的变化特征,并对土壤氮素表观盈亏进行了估算。【结果】玉米地上部生物量和吸氮量均随施氮量的增加而增大,其中推荐施肥处理的生物量和吸氮量均最高。施氮显著增加了0～90 cm土层中的无机氮含量。2个习惯施肥处理土壤的硝态氮含量受降雨量的影响较大,且下移明显;推荐施肥处理可明显降低硝态氮在土壤中的残留。土壤氮素表观盈亏取决于氮肥用量,2006年农民习惯施肥1处理的土壤氮素表观盈余量最高,且多以残留硝态氮的形式累积在深层土壤中。【结论】在东北黑土春玉米连作区,氮肥一次性基施会导致土壤中的无机氮高残留,增加氮损失,易对该地区的生态环境造成威胁,本试验中的推荐施肥是较好的施肥方式。     

控制灌溉条件下水稻施肥水平与产量关系研究

为探索控制灌溉条件下水稻施肥水平与产量关系,以水稻品种龙盾104进行了不同施肥水平的3次重复试验。试验结果表明:在180～480 kg/hm2试验施肥水平范围内,施肥水平与产量之间存在着极显著相关关系;在现有施肥技术水平条件下,增量施肥的增产效应逐渐减少,直到420 kg/hm2施肥水平时产量达到最高,其后随施肥水平的增加反而产生了负面的减产效应;在目前7 500 kg/hm2水稻平均产量基础上达到适度增产目标,施肥水平最低应控制在200 kg/hm2水平;在保证一定单产水平条件下,应尽量采取少施化肥措施,严禁采用400 kg/hm2以上施肥水平的水稻生产方式。     

不同密度和施肥量对党参品质及其病害程度的效应研究

针对影响党参等级、浸出物、农残、重金属和病害率的栽植密度和施肥量二因素,采用2因素8水平3重复随机区组法进行研究。结果表明,一等品比例较小且集中于60万株/hm2处理;二等品所占比例最大的是90万株/hm2和360 kg/hm2组合。二等品总额中,施肥量相同条件下,所占比例大小顺序是60万株/hm2＞90万株/hm2＞75万株/hm2＞105万株/hm2处理;所有产品以三等品为主;浸出物全部高于标准值,大于70.0%的有4个组合;在密度相同条件下,As、Cu含量最大值基本都在360 kg/hm2施肥量下产生;Pb最大值则在0施肥下产生;Cd基本都趋近于0.01%;Hg含量规律性不强。根病害率最低的是75万株/hm2和360 kg/hm2组合,为1.48%。密度和施肥量科学合理的配置不仅对品质有重要意义,而且也有助于提高商品性。