除草剂草甘膦的性质及环境行为综述

草甘膦是一种广谱、非选择性芽后除草剂,它被越来越广泛地应用于农业。本文总结了草甘膦的一些基本性质及其在环境中的行为和降解机理,概述了国内外的研究现状,及影响其在土壤环境去向的一些因素,如土壤性质、磷酸盐、重金属和DOC的存在等,为进一步研究提供一些建设性的参考。     

大同市区主要蔬菜生产基地环境质量评价分级

对山西省大同市区主要蔬菜生产基地进行环境质量评价及其分级结果表明,该区主要蔬菜生产基地环境质量总体优良,完全满足目前国家所规定的无公害蔬菜或绿色食品产地环境质量的要求。     

仙客来栽培研究进展

主要从生物学特性、环境调控、激素调控等几方面对国内外仙客来栽培方面的研究情况进行了综述,同时对研究中存在的问题进行了分析,并提出了今后的研究方向和思路。     

转基因作物环境安全性研究进展

随着转基因作物在全球范围内的广泛应用,转基因作物的环境安全性问题日益受到重视,科研工作者们对此开展了大量的研究工作。本文对近年来这方面的研究成果进行了综述,主要内容包括:1)转基因作物的杂草化问题,这里面又包含两层含义,一是转基因作物自身的杂草化问题,多数研究表明转基因并没有提高作物的生存竞争能力,在没有选择压力的自然条件下,即使转入了抗病抗逆基因,转基因植株的生存竞争能力也没有增加,因此杂草化的可能性很小;二是转基因作物通过基因漂移使得同种或近缘野生种或得某种抗性而成为更加难以防除的“超级杂草”,由于不同植物种间杂交能力不同,外源基因转移并稳定遗传的几率受到多种因素的影响,不同作物的风险性也不同,因此必须经过长期的监测才能得出科学的结论;2)转基因作物对作物遗传多样性、物种多样性及生态系统多样性的影响:多数观点认为转基因作物会通过基因漂移,外来基因在农家品种或野生种中固定及其竞争优势导致遗传多样性减少乃至丧失,也有观点认为,从长远看,转基因作物将会增加作物的生产力,从而少用农田,少用农药,有助于保护生物多样性;转基因作物对物种多样性的影响正反两方面的报道均有,有待进一步的研究,尤其是研究分析方法亟待规范;转基因作物对生态系统多样性的影响仍在研究争论之中,尚无定论。     

Intensification of New Zealand beef farming systems

This study used whole-farm management, nutrient budgeting/greenhouse gas (GHG) emissions and feed formulation computer tools to determine the production, environmental and financial implications of intensifying the beef production of typical New Zealand (NZ) sheep and beef farming systems. Two methods of intensification, feeding maize silage (MS) or applying nitrogen (N) fertiliser, were implemented on two farm types differing in the proportions of cultivatable land to hill land (25% vs. 75% hill). In addition, the consequences of intensification by incorporating a beef feedlot (FL) into each of the farm types were also examined.Feeding MS or applying N fertiliser substantially increased the amount of beef produced per ha. Intensifying production was also associated with increased total N leaching and GHG emissions although there were differences between the methods of intensification. Feeding MS resulted in lower environmental impacts than applying N even after taking into account the land to grow the maize for silage. Based on 2007/08 prices, typical NZ sheep and beef farms were making a financial loss and neither method of intensification increased profitability with the exception of small annual applications of N, especially to the 75% hill farm. These small annual additions of N fertiliser (<50 kg N/ha/yr applied in autumn and late winter) resulted in only small increases in annual N leaching (from 11 to 14 kg N/ha) and GHG emissions (from 3280 to 4000 kg CO₂ equivalents/ha). Limited N applications were particularly beneficial to 75% hill farms because small increases in winter carrying capacity resulted in relatively large increases in the utilisation of pasture growth during spring and summer than the 25% hill farms. Intensification by incorporating a beef feedlot reduced environmental emissions per kg of beef produced but considerably decreased profitability due to higher capital, depreciation and labour costs. The lower land-use capability farm type (75% hill) was able to intensify beef production to a proportionally greater extent than the higher land-use capability farm (25% hill) because of greater potential to increase pasture utilisation associated with a lower initial farming intensity and inherent constraints in the pattern of pasture supply.     

植物对UV-B辐射增强响应的研究进展

分析了大气中臭氧层变薄的现状、原因及光化学机制，阐述了近年来国内外研究紫外线B辐射增强对植物生长发育的影响及其适应性机制，指出当前该研究领域存在的问题及今后加强研究的方向。     

环保型长效化肥聚脲甲醛的合成研究

合成了环保型长效聚脲甲醛化肥 ,并对其合成的全过程进行了研究 ,结果表明反应温度为50℃～ 6 0℃ ,反应的第一阶段 pH值为 8,反应的第二阶段 pH值小于 4时 ,能获得较高产率的制品 ,最后对产物进行了表征     

亚热带小流域不同沉积区土壤粘粒矿物的演变

在亚热带丘陵河谷地小流域范围内地表物质的迁移常可导致不同沉积区物质组成的变化 .从黄泥土→洪积泥砂土→培泥砂土 ,随着搬运距离的增加 ,其粘粒矿物组成发生了一系列的变化 ;高岭石逐渐下降 ,云母逐渐增加 ,蛭石渐趋下降消失 ,而绿泥石则逐渐形成 ;同时赤铁矿、针铁矿也先后下降消失 .矿物的演化与沉积物所处环境的水分条件及溶液中盐基物质和酸碱度变化有关     

Evaluating a multi-level subsurface drainage system for improved drainage water quality

This paper describes a multi-level drainage system, designed to improve drainage water quality. Results are presented from a field scale land reclamation experiment implemented in the Murrumbidgee Irrigation Area of New South Wales, Australia. A traditional single level drainage system and a multi-level drainage system were compared in the experiment in an irrigated field setting. The single level drainage system consisted of 1.8 m deep drains at 20 m spacing. This configuration is typical of subsurface drainage system design used in the area. The multi-level drainage system consisted of shallow closely spaced drains (3.3 m spacing at 0.75 m depth) underlain by deeper widely spaced drains (20 m spacing at 1.8 m depth). Data on drainage flows and salinity, water table regime and soil salinity were collected over a 2-year period.     

重金属在土壤载体中的行为和环境响应

综述了21世纪初重金属在土壤环境中发生的吸附/解吸、溶解/沉淀、氧化/还原、络合(螯合)等行为的影响因素,如粘土矿物类型、微生物、腐殖质、pH、重金属性质、土壤酶和人为活动等方面的研究结果,得到了比较深入的进展。同时也显现了在复杂的野外条件下,重金属的行为特征研究明显不足;与植物的吸富关系研究尚处于起步阶段;不同区域和土壤类型中重金属及其化合物的行为差异缺乏科学的解释;重金属污染土壤的修复技术还存在风险;重金属复合污染研究也需进一步定量化。