用生态经济型植物控制豚草的"绿色污染"   总被引：5，自引：0，他引：5  

周早弘  舒洪岚 《江西林业科技》2004,(1):37-39

豚草是一种严重危害农业生产、人体健康和生物环境的恶性杂草，是一种典型的“绿色污染”。根据群落演替规律，采用具有生态和经济功能的树种创造不利豚草生长的环境，人为创建多物种和谐共存的植物群落，能降低豚草的种群优势，使单一种群优势转变为良性演替的生态系统。  相似文献   

Societal expectations of livestock farming in relation to environmental effects in Europe     

J.A. Milne 《Livestock Production Science》2005,96(1):3-9

The potential environmental effects of livestock farming are mainly associated with intensification of poultry, pig and dairy cow production systems. The major impacts are mainly caused by housing of livestock, which can lead to air and water pollution associated with nitrogen and phosphorus emissions and losses from manure. European countries regulate the potential for these types of pollution through a number of mechanisms, which have received wide public acceptance. In grazing systems, nitrogen pollution, associated with the use of nitrogen fertilizer, is also the subject of legislation. Perhaps because of this regulatory approach, surveys of the public have found that human food quality and animal welfare are more important issues than effects on air and water quality when considering livestock systems.Variation in stocking rates of grazing ruminants can change the structure and composition of pastures with potential impacts on biodiversity and the production of methane, a greenhouse gas. In European countries, maximum stocking rates have been set to reduce these impacts. Surveys of the European public have suggested that they are willing to pay for the mitigation of these environmental effects but that they also value strongly the cultural component of grazed livestock systems. There are few underlying concepts about how society views the environmental impacts of livestock systems. These are used to conclude that current attitudes are likely to prevail in the next decade.  相似文献   

三江源区高寒草原土壤湿度变化特征及与气候因子的关系   总被引：1，自引：0，他引：1  

郭连云 《草业科学》2018,35(1):46-53

利用青海省三江源区兴海县牧业气象站1999-2016年高寒草原土壤湿度、牧草生育期资料,分析了高寒草原土壤湿度的年、季变化特征以及牧草生长季不同生育期土壤湿度的变化特征及与气候因子的关系。结果表明:高寒草原0-10、10-20、20-30、30-40和40-50 cm土壤湿度均随年际延长呈增加趋势,春季除40-50 cm土层外,其他各层土壤湿度均随年际延长呈显著增加趋势(P<0.05)。高寒草原牧草生长季的土壤相对湿度随年际延长呈显著上升趋势(P<0.05),且与生长季降水量之间呈极显著正相关关系(P<0.01)。随着气候变化,牧草抽穗、开花、成熟和枯黄期的土壤相对湿度随年际延长呈显著增加趋势(P<0.05)。牧草抽穗期、枯黄和全生育期的土壤湿度与气温呈显著负相关关系(P<0.05)。高寒草原牧草生长季土壤湿度的增加有利于草地植被生长。  相似文献   

西吉县农用地膜应用污染现状及对策     

马兴华  王攀峰 《青海农林科技》2014,(3):94-95

本文就西吉县农用地膜的应用现状和污染现状进行了分析,并就这一现状提出了促进旱作农业可持续发展的对策措施。  相似文献   

小麦白粉病菌越夏,越冬和春季菌源毒性结构比较     

王锡锋  张忠山 《植物病理学报》1995,25(4):301-305

 分析了1992年和1993年不同时期采集的小麦白粉病菌越夏、越冬和春季菌源共238个菌株的生理小种、毒性基因结构和对9个推广品种的毒力频率。结果表明三种菌源在生理小种和毒性基因组成及出现频率是相似的,对9个推广品种的毒力频率均较高。这样在白粉病菌毒性和品种抗病性研究中,可以采集应用越夏和越冬菌株标样,避免了夏季高温季节保存菌株的工作;而且从毒性结构方面进一步证实白粉病菌主要以分生孢子在夏季侵染高海拔地区的自生麦苗而越夏,再逐渐扩展至秋播麦苗越冬后导致春季大田发病,病菌的子囊孢子在平原地区侵染循环上作用不大。  相似文献   

市郊菜园土壤污染及治理   总被引：11，自引：0，他引：11  

李佩祥  刘宗佩 《长江蔬菜》1996,(2):32-34

针对衡阳市郊菜园土壤受到污染的实际，分析了主要污染源，提出了控制与治理污染的措施。  相似文献   

The potential contribution of separation technologies to the management of livestock manure   总被引：1，自引：0，他引：1  

C.H. Burton   《Livestock Science》2007,112(3):208-216

Separation processes have a distinct role in the management of livestock slurries, but it is important to recognise their limitations. Such technology can direct certain manure components into a small volume of a concentrated stream which is useful for the production of organic products in subsequent processes. Equipment generally falls into systems based either on mechanical screening (which can produce a fibrous and seemingly dry product), filtration processes (producing a cake), or sedimentation leading to a sludge product. Although physical separation can remove up to 80% of the total solids content from livestock manures, this will only include a relatively small part of the soluble nutrient and of the reactive organic matter; this is particularly so where separation is based on screens. The complete removal of all suspended matter (total clarification) of an effluent is theoretically possible by settling — a decanter centrifuge will accelerate the process. This can remove most of the phosphorous, especially if coupled with chemical pre-treatment to raise the pH. However, the clarified stream still retains a significant polluting potential in terms of the residual nitrogen content (as ammonia) and potassium. Only membrane separation can greatly reduce the potassium concentration, but such technology is rarely suitable for the farm situation.  相似文献   

青藏高原江河源区退化草地人工改良措施对高原鼠兔种群动态影响   总被引：1，自引：0，他引：1  

张清香  严作良周立 《四川草原》2006,(5):33-36

通过对江河源区退化草地采取建植人工和半人工草地的措施进行改良,以影响害鼠(高原鼠兔)种群,达到防治鼠害的目的。  相似文献   

Gene Expression of Enzymes for Starch and Sucrose Metabolism and Transport in Leaf Sheaths of Rice (Oryza sativa L.) during the Heading Period in Relation to the Sink to Source Transition     

《Plant Production Science》2013,16(3):178-183

Abstract

Leaf sheaths of rice plants are known to temporarily accumulate starch prior to heading, which is subsequently remobilized and transported into the panicle after heading. We investigated the time course for both carbohydrate content and steady state mRNA levels of enzymes related to starch and sucrose metabolism in the rice leaf sheath (Oryza sativa L. cv. Nipponbare). Leaf sheaths from the second leaf below the flag leaf accumulated high levels of starch before heading but they rapidly decreased after heading. In contrast, the flag leaf sheath did not accumulate as much starch. In the second leaf sheath, the mRNA levels of enzymes involved in starch synthesis, ADP glucose pyrophosphorylase (EC 2. 7. 7. 27), soluble starch synthase (EC 2. 4. 1.21) and branching enzyme (EC 2. 4. 1. 18) were high before heading, which coincided with rapid accumulation of starch. The mRNA levels of sucrose synthesis enzymes, cytosolic FBPase (EC 3. 1. 3. 11) and sucrose phosphate synthase (EC 2. 4. 1. 14), and the sucrose transporter (OsSUTI) increased at the time of heading, which was largely coincident with a decrease in the mRNA levels of starch synthesis enzymes. In the flag leaf sheaths, changes in mRNA levels of starch synthesis enzymes were not pronounced, however mRNA levels of sucrose synthesis enzymes and the sucrose transporter showed a clear increase throughout the heading period. The different characteristics observed between the two leaf sheaths will be discussed in relation to the sink to source transition.  相似文献   

浅谈我国农田土壤重金属污染现状及修复研究          下载免费PDF全文

朱雅琪 《现代农业科技》2024,(5)

农田土壤重金属污染导致农作物重金属含量超标,这些重金属随食物链进入人体内,对人体健康造成危害。了解农田土壤重金属污染现状、重金属污染对农作物的危害,以及污染农田的治理修复,对维护人体健康具有重要意义。本文综述了我国农田土壤重金属污染现状,分析了农田土壤重金属污染可能对农作物造成的影响,概括了目前农田土壤重金属污染的主要治理方式,并分析了这些治理方式的差异性和优缺点,对未来农田土壤重金属污染治理的方向作出了展望。为该领域初学者了解该领域研究方向、发展趋势和研究热点提供了指导,也为我国农田土壤重金属污染治理的进一步研究提供参考。  相似文献