48%氟乐灵EC防除新疆地膜棉田杂草效果研究

研究表明,地膜棉田膜内杂草较膜外杂草种群数量多,生长量大,北疆地区早春气温偏低,膜内温度增高的灭草作用有限,除草剂播种前土壤处理是有效控制地膜内杂草的优良措施。地膜棉田播前施用48%氟乐灵EC1125~1687.5mL/hm2可有效控制狗尾草、稗草、反枝苋、灰藜等杂草,药后第45d对膜内杂草株防效和鲜重防效分别达94.7%~98.6%和93.9%~98.3%,对膜外杂草株防效和鲜重防效分别达78.0%~86.5%和83.7%,对地膜内杂草的防效优于对地膜外杂草的效果,对棉花较为安全。     

数据库技术在FAO Penman-Monteith公式中的应用

参考作物蒸发蒸腾量是进行实时灌溉预报和农田水分管理的主要参数,将数据库技术应用到FAO Penman-Montdth公式的计算中,能降低参考作物蒸发蒸腾量计算的工作量.经编程后系统整体界面友好、结构合理、操作简单,使参考作物蒸发蒸腾量的计算快捷、准确,该系统能具有较强的实际应用价值.     

Persistence of toxins and cells of Bacillus thuringiensis subsp. kurstaki introduced in sprays to Sardinia soils

Sprays of commercial insecticidal preparations of the bacterium, Bacillus thuringiensis subsp. kurstaki (Btk), usually a mixture of cells, spores and parasporal crystals, have been used for the last 10 yr in Sardinia (Italy) to protect cork oak forests against the gypsy moth (Lymantria dispar L.). Until now, the protective antilepidopteran efficacies of each of the various spray treatments rather than their effects on the environment have been evaluated. Consequently, the persistence of Btk and its toxin, released in sprays (FORAY 48B^®), in soils of cork oak stands, located in Orotelli, Tempio Pausania and Calangianus (Sardinia), were investigated. In the Calangianus soil, the numbers of Btk remained essentially constant for 28 months (the longest time studied) after spraying, indicating that Btk was able to compete with the indigenous microbial community; the toxin was detected 28 months after spraying by immunological assay, but at a reduced concentration; and the larvicidal activity decreased essentially linearly to 14 months and then decreased markedly between 14 and 28 months. In the Tempio Pausania and Orotelli soils, cells of Btk were detected, whereas the toxin was not detected by immunological and larvicidal assays, 52 and 88 months (the longest times studied) after spraying, respectively. The numbers of Btk cells detected were probably too low to account for the presence of the toxin in all of the soils studied, as there was no correlation between numbers of Btk and toxin detected by immunological assays (correlation coefficient of −0.66) in the Calangianus soil. Our results indicated that Btk and its toxin introduced into soils in sprays can persist for long periods (at least 88 months for Btk and at least 28 months for its toxin).     

森林面临的大挑战——淡水资源短缺

联合国粮农组织对世界森林与淡水的问题极为关注，并于2003年3月10～14日提出了《森林与淡水的问题与选择方案》。文中简要地介绍了地球淡水短缺对人类的威胁，森林对集水区的作用，集水区面临的问题，联合国森林与淡水行动计划及未来的发展方向等，供研究和制定解决淡水短缺战略参考。     

国外食品中农药残留监测概况

本文简要介绍了近年世界卫生组织和联合国粮农组织在保证食品安全中对农药残留的管理情况、各国农药多残留分析方法进展 ,以及欧美和日本等国对食品中农药残留监测的概况 ,并对我国开展农药残留监测和加强管理提出建议     

海滨碱蓬（Suaeda maritima）低亲和性Na+吸收速率的研究

用采自英国苏克塞斯的海滨碱蓬为材料,将铺有滤纸的培养皿中发芽7天的海滨碱蓬幼苗,移栽到育苗盘中溶液培养,用调整过的Hoagland营养液培养海滨碱蓬21天,用150 mmol/L NaCl处理海滨碱蓬0 h、6 h、12 h、24 h、36 h及48 h,测定海滨碱蓬在不同处理时间下根、茎、叶的鲜重、干重及Na+含量。分析Na+吸收速率在48 h内的变化趋势。结果表明,不同处理之间海滨碱蓬Na+吸收速率差异不显著。因此,海滨碱蓬在48 h内的Na+吸收速率基本保持不变,在与Na+吸收途径有关的试验中处理时间设为48 h不仅可以节省人力物力财力,又可以取得事半功倍的良好研究目的。     

Sap flow measurements in young olive trees (Olea europaea L.) cv. Chétoui under Tunisian conditions

Measurements of sap flux were carried out from May 2003 to March 2004 on 6 year-old irrigated olive trees of cultivar Chétoui cultivated at 6 m × 6 m spacing in Mornag (36.5°N, 10.2°E), Northern Tunisia. The aim of the research is to evaluate the sap flux technique for its applicability with young olive trees and to estimate their water consumption under field conditions. Three thermal sensors were implanted in the trunk of three olive trees following to North (N), South-East (SE) and South-West (SW) directions. Data were analyzed following to the procedure of Do and Rocheteau (2002b) that derives from Granier (1985). In this paper, data on probe calibration, wood conductive section estimation and sap flux spatial-variability are presented and discussed. Relationships between sap flux measurements, climate and soil water status have been investigated. Results show that sap flux values vary with sensor position, soil water content and climate demand. Good agreements between sap fluxes and global radiation and reference evapotranspiration measurements were observed. Some variations were recorded under water shortage conditions. Maximum and minimum daily fluxes of 4.5 l and 41.0 l per tree were found in February 2003 and in August 2003, respectively. Maximum transpiration represented only 53% of the crop evapotranspiration as determined by the F.A.O. method.     

48%毒·辛乳油对韭蛆田间防治效果评价

2003~2004年,在山西太原进行了48%毒.辛乳油防治韭菜韭蛆田间药效试验。结果表明,在韭蛆发生期,用48%毒.辛乳油以1 440~2 160g.a.i./hm2剂量顺垄根部喷淋防治,药后3d的防治效果为85.3%~92.9%,药后7~14d的防治效果为83.1%~98.9%,等于或略好于对照农药48%乐斯本乳油1 440g.a.i./hm2,40%辛硫磷乳油3 000g.a.i./hm2和80%敌敌畏乳油2 400g.a.i./hm2处理的防效,持效期可达14d。     

The FAO Geopolitical Ontology: A Reference for Country-Based Information

In 2002, the Food and Agriculture Organization of the United Nations (FAO) published its FAO Country Profiles, an innovative information retrieval system which allows access to FAO's thematic, country-based information from a single entry point. This ontology uses some of the country profiles’ underlying data to provide a reusable resource for the international community, with a more streamlined means of accessing country data. Aimed at improving information management, the ontology facilitates standardized data sharing and interoperability, delivering the most updated geopolitical information. This ontology organizes coding systems and multilingual representations and tracks historical changes to geopolitical data as determined by trustworthy data holders like the United Nations. This article will show how the FAO Country Profiles has defined a new standard in geopolitical ontology and how and why the ontology became a reference for country-based information, as well as discuss future challenges.     

Study of different climatic conditions to assess the role of solar radiation in reference crop evapotranspiration equations

This study aims to assess radiation-based models versus the FAO Penman–Monteith (FPM) model to determine the best model using linear regression under different weather conditions. The reference evapotranspiration was estimated using 22 radiation-based methods and was compared with the FPM. The results showed that the Stephens method estimates the reference evapotranspiration better than other methods in the most provinces of Iran (nine provinces). However, the values of R² were more than 0.9930 for 24 provinces of Iran. The radiation-based methods estimated the reference evapotranspiration near the Caspian Sea better than other regions. The most precise methods were the Berengena–Gavilan, Modified Priestley–Taylor, and Priestley–Taylor methods for the provinces ES (center of Iran), GI and GO (north of Iran) and the Stephens–Stewart method for IL (west of Iran). Finally, a list of the best performance of each method has been presented to use other regions and next research steps according to the values of mean, maximum, and minimum temperature, relative humidity, solar radiation, elevation, sunshine, and wind speed. The best weather conditions to use radiation-based equations are 23.6–24.6 MJ m^?2 day^?1, 12–20°C, 18–24°C, 5–13°C, and <180 hour month^?1 for solar radiation, mean, maximum, and minimum temperature, and sunshine, respectively.