自然农法条件下稻田有益微生物菌群多年施用累积效果

在自然农法条件下,对稻田连续9年施用有益微生物群（EM） 的累积栽培效果进行了研究。连续施用EM 使土壤的养分状况发生了明显的改变,使水稻抽穗期推迟,花期延长,叶色加深。 EM 的应用还能有效地改善产量结构、提高产量,而且应用年限越长,效果越明显,并且有助于改善稻米品质、减少稻米中钾和镁的含量、增加直链淀粉含量和食味评价值,口感较好。EM 的应用在一定程度上可以抑制杂草的发生和生长     

Biodiversity and Dynamics of Planthoppers and Their Natural Enemies in Rice Fields with Different Nitrogen Regimes

Biodiversity both theoretically and practically has relevance in addressing many problems of contemporary agriculture and allows the formation of functional groups that drive key ecosystem processes [1]. One of the most important processes in agroecosystems is pest regulation, because biodiversity is related closely to host-plant resistance, pest management attributes, natural biological control agents and their impacts, and stability as the ecological basis for pest management [2-3]. On one h…     

Control of Aspergillus growth and aflatoxin production using natural maize phytochemicals under different conditions of water activity

The effects of the natural phytochemicals trans-cinnamic acid (CA) and ferulic acid (FA) alone at concentrations of 1-25 mM and in 16 combinations (M: mixtures) on growth and aflatoxin B(1) production by Aspergillus flavus Link and A. parasiticus Speare were evaluated. Studies on growth rate and aflatoxin B(1) production were carried out in vitro in relation to a water activity a(w) of 0.999, 0.971, 0.955 and 0.937. Overall, CA at concentrations of 10 and 20 mM and FA-CA mixtures M3 (20 + 5 mM respectively), M8 (25 + 5 mM), M9 (1 + 10 mM), M10 (10 + 10 mM), M11 (20 + 10 mM), M12 (25 + 10 mM), M13 (1 + 20 mM), M14 (10 + 20 mM), M15 (20 + 20 mM) and M16 (25 + 20 mM) were the treatments most effective at inhibiting growth of the four species assayed. All strains were much more sensitive to all natural phytochemicals tested on growth rate at a(w) = 0.937. CA and the FA-CA mixtures M1 (1 + 1 mM respectively), M4 (25 + 1 mM), M5 (1 + 5 mM), M6 (10 + 1 mM), M7 (20 + 1 mM), M8 (25 + 5 mM), M9 (1 + 10 mM), M10 (10 + 10 mM), M11 (20 + 10 mM), M12 (25 + 10 mM), M13 (1 + 20 mM), M14 (10 + 20 mM), M15 (20 + 20 mM) and M16 (25 + 20 mM) completely inhibited aflatoxin B(1) production by all strains at a(w) = 0.999, 0.971, 0.955 and 0.937. Decreased aflatoxin B(1) levels in comparison with the control were observed with FA at 1, 10, 20 and 25 mM with the strains RCM89, RCM108 and RCM38 at a(w) = 0.971, 0.955 and 0.999 respectively. The data show that CA and FA can be considered as effective fungitoxicants for A. flavus and A. parasiticus in in vitro assay. The information obtained is part of an ongoing study to determine their application at the storage level.     

Repellency of Cinnamomum cassia bark compounds and cream containing cassia oil to Aedes aegypti (Diptera: Culicidae) under laboratory and indoor conditions

Patch and skin bioassays were used in laboratory and indoor tests to evaluate the repellency of (E)-cinnamaldehyde, identified in Cinnamomum cassia Blume bark and essential oil, and a cream containing 5% (w/w) cassia oil against Aedes aegypti (L.) females. Results were compared with those of a known C. cassia compound cinnamyl alcohol, N,N-diethyl-m-toluamide (DEET) and two commercial repellents: MeiMei cream containing citronella and geranium oils and Repellan S aerosol containing 19% DEET. In patch bioassay tests with A. aegypti females, (E)-cinnamaldehyde at 0.153 mg cm(-2) and DEET at 0.051 mg cm(-2) provided 93 and 89% protection at 40 min after exposure. In skin bioassay tests, (E)-cinnamaldehyde at 0.051 mg cm(-2) and DEET at 0.025 mg cm(-2) provided 87 and 95% protection at 30 min after application. (E)-Cinnamaldehyde was significantly more effective than cinnamyl alcohol in both bioassays. In indoor tests with four human volunteers, 5% cassia oil cream provided 94, 83 and 61% protection against A. aegypti females exposed for 30, 50 and 70 min after application respectively. Cassia oil cream was a slightly less effective repellent than MeiMei cream. Repellan S aerosol provided 91% repellency at 120 min after application. Products containing cassia oil merit further study as potential repellents for the protection of humans and domestic animals from blood-feeding vectors and the diseases they transmit.     

水稻覆膜旱作对病虫草害发生程度的影响

就覆膜旱作栽培方式对早稻和单季稻病虫草害、天敌、腐食者等的丰盛度与为害程度影响作了研究。结果表明,稻田覆膜旱作可显著降低早稻纹枯病的发生程度,与常规淹水对照稻田相比,覆盖旱作稻田纵卷叶螟为害率、灰飞虱和蚜虫类虫密度及杂草发生程度无显著差异,但螟虫为害加剧,施肥量仅对照田一半的覆膜田螟虫为害株百分率比对照田提高２．４％～８．５％。水稻覆膜旱作栽培方式和种植密度高低是影响寄生蜂和蜘蛛类密度的主要因子。     

用转基因方法进行抗线虫农作物育种的研究进展

在许多农作物中,植物寄生线虫引起重大损失。有幸的是,某些植物对线虫有抗性,而且存在于栽培种和其近亲野生种中的抗性基因,可以用分子标记方法建立图谱。标记辅助的选择方法已广泛应用于育种工作中,两种抗线虫的基因已经通过定位克隆技术分离出来,并成功地在栽培作物中得到表达。建立线虫抗性的另一个方法是将具有杀线剂效应的基因导入植物中,该方法也已取得了一些进展。     

中国捕食粘虫的步甲种类检索

本文报道了中国捕食粘虫的步甲38种,其中10种为过去未曾报道过,分别为：麻步甲Carabus brandti Faldermann,侧步甲C．latreillei Fischer,黄斑青步甲Chlaenius micans Fabricius,后斑青步甲Ch．posticalis Motschulsky,彩角青步甲Ch．touzalini Andrewes,小短背步甲Curtonotus fodinae(Mannerheim),巨短背步甲C．giganetus(Motschulsky),毛婪步甲Harpalus griseus(Panzer),单齿婪步甲H．simplicidens Schauberger和黑足婪步甲H．roninus Bates。文中给出38种步甲的分类检索表及每个种的地理分布。     

鸡的人工授精与自然交配种蛋孵化对比试验

该试验选用鸡的人工授精种蛋９４０枚及自然交配种蛋９６０枚,做了鸡的人工授精与自然资本种蛋孵化试验,结果表明：鸡人工授精后６ｄ内种蛋受精率平均为９４．５％,７ｄ后,受经极显著降低;人工授精后的种蛋受经及入孵种蛋孵化率均极显著高于自然交配组,两两者的受精种蛋孵化率无明显差异;另外,在试验过程中,还研究了种蛋贮存时间与化结果的关系,发现种蛋贮存期越短,孵化效果越好,贮存期最长不应超过７ｄ。     

新疆玉米害螨天敌种类及其优势种天敌控害效应研究

广泛调查新疆主要玉米产区,采集标本,鉴定出新疆玉米害螨的天敌有2纲12科28种.其中深点食螨瓢(Stethorus punctillum Weise)为优势种天敌,经室内对深点食螨瓢捕食新疆玉米叶螨优势种截形叶螨(Tetranychus truncates Ehara)的功能反应研究,成虫和幼虫均有较强的捕食能力,其中深点食螨瓢成虫对截形叶螨卵、若螨和成螨捕食量分别为:41.58、36.27和28.25头,其功能反应符合HollingⅡ.     

扎龙自然保护区湿地生物生境安全保护

扎龙湿地是国际重要湿地,保持了该区野生生物种类的丰富性和多样性,保存了最完整的湿地生态系统和野生生物特有的遗传性,是我国重要的天然基因库之一.据统计该区具有高等植物469种,隶属于67科,脊椎动物共有365种,隶属于77科,其中国家3级保护植物2种;省濒危植物4种;国家级保护鸟类41种;省级保护动物21种.但是自然条件和人为干扰导致的湿地生境破碎化、湿地污染以及对生物的驱逐效应的不断加剧,使该区生物面临着巨大的危险.本文从湿地生境安全保护的角度,提出了维持扎龙湿地生物多样性及其安全栖息生境的保护对策.