面向对象的农产量预测专家系统设计与实现

本文介绍了用面向对象方法建造农产量预测专家系统的过程。提出了知识表示与推理机制不可分割，并且作了论述，证明向对象方法适合建造专家系统。在此基础上，讨论了面向对象的知识获取方法及原型知识表示，较为形式化地阐明了推理机制，最后讨论了基于Ｃ＋＋的实现技术。     

Europe's Place in the Global History of Biological Exchange

This paper provides a framework for the European history of biological exchange and biological invasion. It distinguishes four main eras of heightened biological exchange. The first came with the introduction to Europe of the neolithic complex of domesticated plants and animals. The second was associated with the increased trade and travel of the pax romana. The third came with increased connections to Asia and the Indian Ocean world in the era of the Crusades. The fourth, well-known to historians, followed from the oceanic navigations of European mariners beginning in the fifteenth century. In all but the last of these, Europe imported far more than it exported in terms of useful species, and most of those exported were earlier imports, mainly from southwest or south Asia.     

Effect of Preharvest Deficit Irrigation on Second Crop Watermelon Grown in an Extremely Hot Climate

As a second crop, watermelons (Citrullus vulgaris, Crimson sweet) were grown in 2003 and 2004 in the Sanliurfa-Harran Plain in southeastern Turkey to determine the effect of preharvest water stress on fruit yield, quality (i.e., soluble solids contents and fruit size), leaf temperature, and some other physiological parameters. Preharvest drip irrigation treatments included (1) complete irrigation cutoff, dry (D); (2) full irrigation based on replenishment of soil water depleted from 0 to 90?cm soil profile (C); (3) 75% full irrigation (IR1); (4) 50% full irrigation (IR2); and (5) 25% full irrigation (IR3) with 3-day irrigation interval. Treatment plots received the same level of irrigation water until the fruit formation stage, except for Treatment D. Then, different water stress levels were imposed on treatment plots. Irrigation water applied to the five respective treatments were 636, 511, 395, 245, and 120?mm in 2003 and 648, 516, 403, 252, and 127?mm in 2004. Results indicated that fruit yield was significantly lowered by reduced water rates. The seasonal average yield response factor (ky) for both years was 1.0, but it was 0.97 for 2003 and 0.98 for 2004. The highest marketable fruit yield, obtained from treatment C, was 32.4?Mg?ha?1 in 2003 and 37.1?Mg?ha?1 in 2004. D, IR2, and IR3 treatments reduced most measured parameters, except for soluble solids contents (SSC). Both the fruit size and SSC were significantly affected by late-season irrigation management; individual fruit weights were significantly reduced, whereas SSC increased in the IR2 and IR3 treatments compared to the control values. The writers’ results clearly indicated that reduced preharvest irrigation was detrimental. Water use efficiency (WUE) was significantly affected by irrigation treatments. Even a 25% reduction in the irrigation amount caused a 15% reduction in marketable yield. This indicates that deficit irrigation in the ripening stage significantly increased water use efficiency. The study demonstrated that a moderate deficit irrigation, which is replenishment up to 50% of soil water depleted in the root zone, can be successfully used to improve WUE under semiarid climatic conditions.     

抗草甘膦作物的发展与草甘膦使用中若干问题

本文论述了转基因抗草甘膦作物最近的发展及草甘膦大面积使用中的一些问题。     

徐州西郊污水浇灌农作物的试验研究

该实验就徐州西郊污水对土壤、农作物和蔬菜的污染程度进行了分析、评价,并就污水对农作物与蔬菜的影响进行了比较。结果表明,徐州西郊污水对土壤和农作物均有显著危害,对蔬菜的污染较之农作物的危害尤甚。     

论云南热职院国际教育合作的路径——基于中泰国际教育合作政策的研究

以云南热职院国际教育合作为例,分析了云南热职院“走出去”发展的现状和主客观制约因素,认为中泰两国政府在高等教育合作层面所出台的系列政策具有助推作用,合作的路径是通畅的,由此提出:提高主观理念上的认识,在客观现实中搭建平台是解决目前制约因素的主要路径.     

陕西安康地区农作物重金属浓度空间变异及污染评价

目的 分析陕西安康地区农作物重金属污染状况.方法 通过测定安康区域不同农作物中6种重金含量,对安康区域农作物重金属污染状况进行分析和评价.采用单项污染指数法,按照GB 2762—2017《食品安全国家标准食品中污染物限量》、国家中药重金属及农药残留标准进行检测,分析安康区域内农作物重金属污染的空间变异,评估其污染状况....     

降雨途径中农作物对核素的截获行为研究现状

核设施运行过程中, 排放的气载放射性核素沉积到土壤或农作物表面并进入食物链, 是计算公众内照射剂量的主要来源, 大气湿沉积-降雨过程中农作物对核素的生态转移过程涉及截获和易位行为。本文调研了国内外降雨途径中农作物对核素截获行为的研究现状, 包括农作物种类、实验方法、影响因素和转移参数, 结合我国现状, 提出了此领域的研究方向和重点。     

Crop Coefficients for Microsprinkler-Irrigated, Clean-Cultivated, Mature Citrus in an Arid Climate

Crop evapotranspiration (ETc) was measured over a clean-cultivated, mature navel orange orchard with microsprinkler irrigation located near Lindsay, California. Hourly mean latent heat flux density was determined as the residual of the energy balance equation with measured net radiation, soil heat flux density and sensible heat flux density estimated using the surface renewal method. The ETc was compared with ETo calculated using hourly weather data and the ASCE-EWRI Penman-Monteith equation. Following pruning and topping of the trees in the spring of 2001, the Kco values slowly increased as the canopy developed in the following season. An average Kco = 0.82 was observed. In the following year, the mean summertime value increased to about Kco = 0.95, and in 2003 and 2004, the summertime value averaged near Kco = 1.00, which is somewhat higher than observed for drip irrigated trees in southwestern Arizona and considerably higher than reported in the widely used Food and Agricultural Organization of the United Nations publications that were based on infrequent surface irrigation.     

Satellite-Based Energy Balance for Mapping Evapotranspiration with Internalized Calibration (METRIC)—Applications

Recent satellite image processing developments have provided the means to calculate evapotranspiration (ET) as a residual of the surface energy balance to produce ET “maps.” These ET maps (i.e., images) provide the means to quantify ET on a field by field basis in terms of both the rate and spatial distribution. The ET images show a progression of ET during the year or growing season as well as its spatial distribution. The mapping evapotranspiration at high resolution with internalized calibration (METRIC) is a satellite-based image-processing procedure for calculating ET. METRIC has been applied with high resolution Landsat images in southern Idaho, southern California, and New Mexico to quantify monthly and seasonal ET for water rights accounting, operation of ground water models, and determination of crop coefficient populations and mean curves for common crops. Comparisons between ET by METRIC, ET measured by lysimeter, and ET predicted using traditional methods have been made on a daily and monthly basis for a variety of crop types and land uses. Error in estimated growing season ET was 4% for irrigated meadow in the Bear River basin of Idaho and 1% for an irrigated sugar beet crop near Kimberly, Id. Standard deviation of error for time periods represented by each satellite image averaged about 13 to 20% in both applications. The results indicate that METRIC and similar methods such as SEBAL hold substantial promise as efficient, accurate, and inexpensive procedures to estimate actual evaporation fluxes from irrigated lands throughout growing seasons.