共查询到20条相似文献，搜索用时 375 毫秒
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近年来,我国农业气象灾害呈现出高发趋势,对农业生产及农业经济发展影响巨大,做好农业气象防灾减灾工作迫在眉睫。人工影响天气在农业气象防灾减灾中发挥着重要作用,通过利用科技手段改变天气,降低天气对农业生产的不利影响,保障农业安全稳定生产。首先概述了人工影响天气的主要内容,其次分析了人工影响天气在农业气象防灾减灾中的作用,最后探讨了人工影响天气在农业气象防灾减灾中的应用对策。 相似文献
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研究人民币汇率变动对我国茶叶出口贸易影响的目的在于了解汇率对中国出口贸易的基本影响,找到提高我国茶叶出口贸易水平的途径。本文介绍了汇率变动对我国进出口贸易的整体影响,分析了我国茶叶出口贸易受人民币汇率变动的影响,提出茶叶出口贸易规避汇率影响的举措如下:提高出口茶叶附加值,以技术对抗汇率变动的影响;打造具有自主知识产权的知名茶叶品牌。 相似文献
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茶文化源于中国,通过对外出口贸易传入西欧国家,其中英国和美国受到了极大的影响,并赋予其当地的特色,将其发扬光大。本文主要介绍了红茶文化与英美文化,并进一步分析了英伦红茶对英国文学的影响以及红茶对于美国文学的影响。 相似文献
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油菜花角期叶片对产量的影响 总被引：4，自引：0，他引：4
本试验通过去叶处理,研究了不同部位的叶片对油莱籽粒产量的影响,结果表明:在花角期叶片对籽粒产量的影响是随生育阶段的推进而不断减小的;主茎叶对角果数影响较大,分枝叶对每角粒重影响较大,并且主要是分别影响了分枝上的角果数和每角粒重;对主茎上籽粒产量的影响是主茎叶大于分枝叶,对分枝上籽粒产量的影响是分枝叶大于主茎叶,而对全株产量的影响仍是分枝叶大于主茎叶。 相似文献
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研究茶多酚对运动能力影响的目的在于了解茶多酚的特点及其影响运动能力的各个方面,找到运用茶多酚提升运动能力的举措。本文介绍了茶多酚的特点,分析了影响人体运动能力的因素,茶多酚对运动能力的影响;提出使用茶多酚提高运动能力的措施如下:坚持合理、科学的使用原则;坚持长期原则。 相似文献
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经济社会的不断发展,推动生态旅游建设,而茶园景观则是生态旅游中的重要内容。本文基于低影响开发模式分析了茶园景观设计开发的必要性和可行性,探讨了低影响开发模式下,茶园景观设计目标和开发策略,并重点阐述了低影响开发在茶园景观设计中的应用途径和方法。 相似文献
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《Journal of Crop Improvement》2013,27(1):123-138
Abstract Traditional methods of weed management have not considered the microbial or other biological factors that influence plant growth; however, incorporating this knowledge may expand weed management possibilities to develop weed-suppressive soils. Alternative weed management strategies are needed to expand the capability of weed control as weed pressures continue to limit optimum yield and the use of synthetic chemical herbicides for weed control becomes more restricted. Biotic factors can influence the distribution, abundance, and competitive abilities of plant species. It has been shown that soil microorganisms are capable of suppressing weeds in the field, and seed decay phenomena are most likely microbial. It is imperative that an understanding of soil microorganisms and their ecology be developed, so that they may be used to benefit agriculture, especially weed management. Further study is required so that the ecological and biological effects of the resident soil microbial population on weed growth can be used effectively in weed management strategies to assist in reducing inputs. 相似文献
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东部地区大豆田杂草种群演变趋势及其化学防除 总被引：16，自引：2，他引：14
根据１９８２,１９９２和１９９７年黑龙江省东部地区大豆主要种植区杂草的调查结果,明确了该地区大豆田杂草种群及群落演变趋势及影响种群演变的因素。介绍了大豆田除草的关键时期,常用除草剂种类及其使用技术。 相似文献
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Weed control thresholds have been used to reduce costs and avoid unacceptable yield loss. Estimation of weed infestation has often been based on counts of weed plants per unit area or measurement of their relative leaf area index. Various linear, hyperbolic, and sigmoidal regression models have been proposed to predict yield loss, relative to yield in weed free environment from early measurements of weed infestation. The models are integrated in some weed management advisory systems. Generally, the recommendations from the advisory systems are applied to the whole field, but weed control thresholds are more relevant for site-specific weed management, because weeds are unevenly distributed in fields. Precision of prediction of yield loss is influenced by various factors such as locations, yield potential at the site, variation in competitive ability of mix stands of weed species and emergence time of weeds relative to crop. The aim of the review is to analyze various approaches to estimate infestation of weeds and the literature about yield loss prediction for multispecies. We discuss limitations of regression models and possible modifications to include the influential factors related to locations and species composition in context of their implementation in real time patch spraying. 相似文献
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《Journal of Crop Improvement》2013,27(1):9-29
Abstract Weed thresholds are an integral component of an integrated weed management system (IWM). In this paper we review the literature on weed thresholds and examine the theory and applicability of thresholds within the context of a systems approach to IWM. The development of empirical models describing single and multi-species thresholds are reviewed and discussed in terms of the magnitude of weed threshold values in various crops and the importance and limitations of the parameters used to calculate these values. Mechanistic weed threshold crop competition models are suggested as a means of overcoming some of the limitations of empirically based threshold models. A mechanistic approach to the development of weed threshold models is desirable since relative crop and weed responses to environmental factors, cultural practices and the dynamic nature of competition are considered. Guidelines for the application of weed thresholds within a cropping system are outlined. 相似文献
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《Journal of Crop Improvement》2013,27(1):95-121
Abstract Future advancements in crop production will rely on increased understanding of ecological principles that control interactions among cropping system components. Our interest in linking soil quality and weed management derives from the belief that greater understanding of key processes and properties that define soil-weed relationships will lead to the design of agroecosystems with greater capacity and opportunity to suppress weeds. We identified seed-bank persistence, seedling establishment, and interspecific interference as key processes that affect annual weed population dynamics. We then examined how soil processes and properties can affect each of these factors and how, in turn, soil-improving management practices and cropping system design may affect weed dynamics. We established weed-related soil management objectives as: (i) reducing the persistence of seeds in the soil; (ii) reducing the abundance of safe-sites for weed establishment and the filling of available sites; and (iii) reducing crop yield loss caused by a given density of weeds. Soil factors that can be managed to achieve these goals include: (i) chemical, physical, and biological conditions that affect resources required for weed seed germination, establishment and growth; (ii) habitat for herbivores and pathogens that attack weed seeds and seedlings; and (iii) phytotoxin production. We concluded that many as yet unexplored opportunities exist to manipulate the soil environment and to design cropping systems that create multiple weed suppressive conditions at critical junctures of weed seed-bank persistence, establishment, and interference. 相似文献
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The demand for rice to meet the dietary need in low-income countries is expected to witness an exponential rise as the population increases. Meeting the rice demand domestically has remained challenging due to significant yield loss caused by several biotic and abiotic factors. Among these factors, one of the most important is the high weed pressure that ravages the upland rice ecology. In Nigeria, several independent weed control techniques, such as physical, chemical and cultural methods, have been recommended and adopted for weed control across varying rice upland ecologies. However, outcomes of these approaches when used independently have not consistently led to an increase in yield. There remains an outstanding deficit between the actual yield and the potential rice yield. This review aimed to identify potential research gaps, and quest effective and sustainable weed management strategies in smallholder upland rice farming systems in Nigeria. A critical analysis of studies suggests the potential of sustainable weed management practices if adopted and adapted smartly in different upland ecologies in Nigeria. Competitiveness of upland rice against weeds can be enhanced through strategic integration of weed competitive cultivars, optimum nitrogen application timings (within weed-free periods), uniform plant spacing, and high seeding rates, with conventional herbicide/manual weed control practices. However, such management practices can only be engaged where inputs are supplied on time and the technical know-how is extended to farmers. The review equally highlights potential research gaps for further studies. 相似文献
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湖北省油菜主产区杂草群落的数量分析 总被引：2，自引：0，他引：2
采用七级目测法定量调查了湖北省油菜主产区28个样点的杂草发生情况,应用主成分分析法对杂草群落进行了数量分析。结果表明,28个样点可以分为4个聚类群,即江汉平原鄂北旱茬油菜田、鄂东南旱茬油菜田、江汉平原稻茬油菜田和鄂东南稻茬油菜田。轮作制度与地理因素决定了湖北省油菜主产区杂草群落的分布。根据综合草害指数和发生频率明确了各聚类群相应的优势杂草,并就该地区油菜田杂草发生的特点提出了治理策略。 相似文献
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《Journal of Crop Improvement》2013,27(1):139-166
Abstract Studies of soil weed seed banks are of relatively recent origin considering their importance as sources of diversity and continued occupation of many types of habitats, including agroecosystems. The management of weed seed banks is based on knowledge and modification of the behavior of seeds within the soil seed bank matrix. The behavior of seeds defines the phenotypic composition of the floral community of a field. Selection and adaptation over time have led to the highly successful weed populations that exploit resources unused by crops. The weed species infesting agricultural seed banks are those populations that have found successful trait compromises within and between the five roles of seeds: dispersal and colonization, persistence, embryonic food supply, display of genetic diversity, and as a means of species multiplication. Diverse weed seed populations provide seed banks the opportunity to exploit any change in conditions to ensure their enduring survival and spread. The soil seed bank matrix is the spatial arrangement of environmental and physical factors over time. The behavior of soil seed banks at any level of biological, spatial, or temporal organization is a consequence of the accumulated, emergent behavior at lower levels of organization. Weed seed behavior arises from their sensitivity to environmental conditions within the physical structure of the soil seed bank. This sensitivity is reflected in changes of short duration (e.g., germination), during the annual life cycle, over multiple years (e.g., population shifts), and over evolutionary time. Understanding the processes that drive and control seed behavior will allow us to manipulate and manage weed seed banks in an economic and sustainable manner. This knowledge will allow us to implement improved, more informed, weed management systems and strategies. Important weed bank management strategies include prevention of seed introduction on farm, acquisition of weed biology information (including predictive tools), decision making about weed seed infestation levels and their implementation (eradication, reduction, tolerance), weed seed population shifts (within the seed bank, between species, increased diversity), and manipulations encouraging beneficial weed species. Environmental modification and changes in cropping systems can also be of considerable strategic importance in weed management. 相似文献
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草害是造成大豆减产的主要因素之一。本试验通过系统观察大豆田杂草消长规律,对大豆播后不同时期人工除草的保产效果进行了对比试验研究。结果表明:本地大豆田杂草有两个发草高峰,出现时间分别在大豆播后18～30天和37～48天。大豆田杂草防除临界期为大豆播后18～30天,在此期内除草一次,保产效果最佳。 相似文献