对保证学生评教质量的思考

学生评教是教育评价体系中重要的构成部分，为保证学生评教质量，应建立科学完善的学生评教指标体系，选用科学的学生评教实施方法。     

中国荷斯坦奶牛产奶量与乳品质互作关系探讨

以一个奶牛场的336头泌乳牛为研究对象,选取了降低产奶量前、降低产奶量期间、恢复产奶量期间和提高产奶量期间4个阶段,研究了每个阶段的产奶量与乳品质一些指标间的相关性。经分析,产奶量、乳蛋白质率、乳脂肪率、非脂乳固体含量、乳糖含量这5个指标相互之间均有极显著的正相关性。     

旅游开发对祁门牯牛降自然保护区水质的影响

2006年9月至2007年6月对祁门牯牛降景区牯牛湖的浮游植物进行了调查，经鉴定共有浮游植物99属种，隶属于5门61属。采用“污染指示种”对牯牛湖的水质污染状况进行了评价，结果表明：旅游开发对祁门牯牛降自然保护区牯牛湖的水质影响微小。     

膜下滴灌对加工番茄水分利用效率与品质的影响

在新疆石河子研究了膜下滴灌对加工番茄耗水特征、水分利用效率和品质的影响。结果表明,膜下滴灌处理番茄总耗水量较常规沟灌降低8.37%~59.33%,总耗水量也随滴灌量的增加而增加。膜下滴灌加工番茄耗水量以盛果期最高,开花座果期次之,成熟期和苗期最低,其日耗水强度表现出先升后降的变化趋势,总体低于常规沟灌处理。与常规沟灌相比,膜下滴灌能提高番茄果实硬度、可溶性固形物、番茄红素、Vc、可溶性酸和总糖含量以及糖酸比。从节水高产灌溉的角度考虑,当地加工番茄膜下滴灌量以6150 m3/hm2较为适宜。     

Sodicity and salinity in a Brazilian Oxisol cultivated with sugarcane irrigated with wastewater

Changes in soil sodicity-salinity parameters are one of the most characteristic alterations after treated sewage effluent (TSE) irrigation in agro-systems. Considering the importance of these parameters for agricultural management, as well as the economical value of sugarcane for Brazil, the present study aimed at evaluating effects on soil sodicity and salinity under tropical conditions over 16 months of TSE irrigation in a sugarcane plantation at Lins, São Paulo State, Brazil. Soil samplings were carried out in February 2005 (before planting), December 2005 (after 8 months of TSE irrigation) and September 2006 (after 16 months of TSE irrigation) following a complete block design with four treatments and four replicates. Treatments consisted of: (i) control, without TSE irrigation; (ii) T100, T150 and T200, with TSE irrigation supplying 100% (0% surplus, total of 2524 mm), 150% (50% surplus, total of 3832 mm) and 200% (100% surplus, total of 5092 mm) of crop water demand, respectively. Compared to initial soil conditions, at the end of the experiment increases of exchangeable sodium (from 2.4 to 5.9 mmol_c kg⁻¹), exchangeable sodium percentage (ESP) (from 8 to 18%), soluble Na (from 1.4 to 4.7 mmol L⁻¹) and sodium adsorption ratio (SAR) of soil solution (from 3.6 to 12.6 (mmol L⁻¹)^0.5) were found in the soil profile (0-100 cm) as an average for the irrigated plots due to high SAR of TSE. Associated with the increments were mostly significant increases in clay dispersion rates at depths 0-10, 10-20 and 20-40 cm. Electrical conductivity (EC) of soil solution increased during the TSE irrigation period whereas at the end of the experiment, after short term discontinuation of irrigation and harvest, EC in the topsoil (0-10 and 10-20 cm) decreased compared to the previous samplings. Moreover, despite increasing sodicity over time mainly insignificant differences within the different irrigated treatments were found in December 2005 and September 2006. This suggests that independent of varying irrigation amounts the increasing soil sodicity over time were rather caused by the continuous use of TSE than by its quantity applied. Moreover, also plant productivity showed no significant differences within the TSE irrigated plots. The study indicates that monitoring as well as remediation of soil after TSE irrigation is required for a sustainable TSE use in order to maintain agricultural quality parameters.     

核主成分分析方法在农业机械性能综合评价中的应用

核主成分分析(KPCA) 方法是通过非线性变换,将指标原变量空间映射到高维特征空间,并在高维特征空间中进行主成分分析的方法.为此,将该方法应用于农业机械性能综合评价的研究中,不仅实现了数据降维,而且还有效地处理了各指标的非线性影响,与其它评价方法相比较,评价结果更客观且指导性较强,取得了良好的效果.     

我国各地区经济实力综合评价研究

介绍了主成分与聚类分析方法原理,以8项经济指标构建了综合反映各地区经济实力的评价体系,分析了经济指标间的关系和影响经济发展的主要因素,并对2006年我国大陆31个省(直辖市、自治区)的经济数据,利用多元统计中的主成分和聚类分析方法,对各地区综合经济实力进行了排序和分类.     

土壤水分含量与施肥量对辣椒产量与品质的影响

通过盆栽大方线辣椒,研究了土壤水分含量与施氮量对辣椒果实产量和品质的影响。结果表明,土壤水分含量和施氮量对产量影响显著,其中W2N2(土壤水分下限为60%Q,0.2gN/kg干土)产量最高;同一土壤水分含量,施氮能显著的增加辣椒素、维生素C、干物质和可溶性糖等物质含量,但施氮过多,辣椒素、维生素C含量下降;同一施氮量,土壤水分含量下降辣椒素、维生素C含量显著增加。综合来看,W2N2产量最高,品质较好。     

林科类专业大学生人文素质基本情况的问卷调查

文章调查和分析了林科类专业大学生人文素质的现状,从家庭背景和生活环境、教育观念、人文素质教育质量三个方面分析了学生人文素质较弱的原因,总结了其主要特征,建议高校转变教育观念,重视人文素质教育,加快林业与人文教育的有机结合,加强人文素质教育硬件和软件建设,提高学生人文素质。     

Information technology and innovative drainage management practices for selenium load reduction from irrigated agriculture to provide stakeholder assurances and meet contaminant mass loading policy objectives

Many perceive the implementation of environmental regulatory policy, especially concerning non-point source pollution from irrigated agriculture, as being less efficient in the United States than in many other countries. This is partly a result of the stakeholder involvement process but is also a reflection of the inability to make effective use of Environmental Decision Support Systems (EDSS) to facilitate technical information exchange with stakeholders and to provide a forum for innovative ideas for controlling non-point source pollutant loading. This paper describes one of the success stories where a standardized Environmental Protection Agency (EPA) methodology was modified to better suit regulation of a trace element in agricultural subsurface drainage and information technology was developed to help guide stakeholders, provide assurances to the public and encourage innovation while improving compliance with State water quality objectives. The geographic focus of the paper is the western San Joaquin Valley where, in 1985, evapo-concentration of selenium in agricultural subsurface drainage water, diverted into large ponds within a federal wildlife refuge, caused teratogenecity in waterfowl embryos and in other sensitive wildlife species. The fallout from this environmental disaster was a concerted attempt by State and Federal water agencies to regulate non-point source loads of the trace element selenium. The complexity of selenium hydrogeochemistry, the difficulty and expense of selenium concentration monitoring and political discord between agricultural and environmental interests created challenges to the regulation process. Innovative policy and institutional constructs, supported by environmental monitoring and the web-based data management and dissemination systems, provided essential decision support, created opportunities for adaptive management and ultimately contributed to project success. The paper provides a retrospective on the contentious planning process and offers suggestions as to how the technical and institutional issues could have been resolved faster through early adoption of some of the core principles of sound EDSS design.