清原县农业机械化发展现状与对策

原县地处辽东山地丘陵区,发展农业机械化具有特殊性。综述清原县农业机械化发展现状,分析其存在的5个主要问题,包括农机装备水平不高、作业水平低、投入和扶持力度还有待继续加大、社会化服务功能不全和推广体系和队伍建设落后,并提出相应的解决对策。     

我国农业机械化发展现状及展望

为提高我国的农业机械发展水平,简要介绍国外农业机械化发展历程,分析我国农机行业发展现状和现存优势,总结我国农业机械化发展中存在的主要问题及不足,展望国内农机业发展趋势。     

Frequency of equine laminitis: a systematic review with quality appraisal of published evidence

Equine laminitis is a highly debilitating disease of the foot. Despite its perceived importance, epidemiological characteristics are poorly understood and the true frequency of the disease remains unclear. The objective of this study was to retrospectively assess previous research to identify publications which provide the best evidence of the frequency of naturally-occurring equine laminitis. A systematic review of English language publications was conducted using MEDLINE (1950–2010), CAB Direct (1910–2010) and IVIS (1997–2010). Additional publications were included by searching bibliographies. Search terms included laminitis, equine, frequency, prevalence and incidence. Studies that allowed frequency estimations to be made for naturally-occurring equine laminitis were included. Information was extracted using predefined data fields, including 13 study quality indicators.Sixty-nine publications were appraised. Ten were considered to provide the most reliable information, estimating the frequency of equine laminitis ranging from 1.5% to 34%. Previous publications estimating laminitis frequency were generally poor quality. Laminitis frequency varied across publications however the publications included in this review focussed on many of the different underlying laminitis aetiologies and comparison of the frequencies between groups would be inappropriate. High-quality evidence-based studies are needed to estimate the true disease frequency in different equine populations.     

桃果实冷害机理及其防治措施研究进展

综述了桃果实在低温贮藏条件下冷害的症状与发生机理,从温度、气调、化学物质处理方面总结了冷害的防治措施,并提出以后研究的方向,为下一步研究提供参考。     

Soil‐ and plant‐based nitrogen‐fertilizer recommendations in arable farming

Under‐ as well as overfertilization with nitrogen (N) will result in economic loss for the farmer due to reduced yields and quality of the products. Also from an ecological perspective, it is important that the grower makes the correct decision on how much and when to apply N for a certain crop to minimize impacts on the environment. To aggravate the situation, N is a substance that is present in many compartments in different forms (nitrate, ammonium, organic N, etc.) in the soil‐plant environment and takes part in various processes (e.g., mineralization, immobilization, leaching, denitrification, etc.). Today, many N‐recommendation systems are mainly based on yield expectation. However, yields are not stable from year to year for a given field. Also the processes that determine the N supply from other sources than fertilizer are not predictable at the start of the growing season. Different methodological approaches are reviewed that have been introduced to improve N‐fertilizer recommendations for arable crops. Many soil‐based methods have been developed to measure soil mineral N (SMN) that is available for plants at a given sampling date. Soil sampling at the start of the growing period and analyzing for the amount of NO ‐N (and NH ‐N) is a widespread approach in Europe and North America. Based on data from field calibrations, the SMN pool is filled up with fertilizer N to a recommended amount. Depending on pre‐crop, use of organic manure, or soil characteristics, the recommendation might be modified (±10–50 kg N ha^–1). Another set of soil methods has been established to estimate the amount of N that is mineralized from soil organic matter, plant residues, and/or organic manure. From the huge range of methods proposed so far, simple mild extraction procedures have gained most interest, but introduction into practical recommendation schemes has been rather limited. Plant‐analytical procedures cover the whole range from quantitative laboratory analysis to semiquantitative “quick” tests carried out in the field. The main idea is that the plant itself is the best indicator for the N supply from any source within the growth period. In‐field methods like the nitrate plant sap/petiole test and chlorophyll measurements with hand‐held devices or via remote sensing are regarded as most promising, because with these methods an adequate adjustment of the N‐fertilizer application strategy within the season is feasible. Prerequisite is a fertilization strategy that is based on several N applications and not on a one‐go approach.     

日本近50年来土壤侵蚀及水土保持研究评述

系统地评价了日本土壤侵蚀及水土保持研究工作，介绍了日本土壤侵蚀及水土保持研究的发展历史和现状，以及主要开展这方面研究的大学、研究机构和主要的研究代表者及其成果。对日本土壤侵蚀及水土保持研究的特点以及所取得的主要成果进行了客观地评价。     

Aspects of phytoremediation of organic pollutants

Phytoremediation is a quite novel technique to clean polluted soils using plants. In theory, phytoremediation methods are cheap, are accepted by the public and, compared to physical or chemical approaches, are ecologically advantageous. Until today, however, there are only a few examples of successful applications. One reason is that the processes involved are complex, and a full clean up may require many years. Plants affect the water balance of a site, they change redox potential and pH, and stimulate microbial activity of the soil. These indirect influences may accelerate degradation in the root zone or reduce leaching of compounds to groundwater. Compounds taken up into plants may be metabolised, accumulated, or volatilised into air. Based on these processes, several phytoremediation methods have been developed: Phytoextraction, rhizofiltra-tion, phytostabilisation, rhizo and phytodegradation, pump and tree, land farming, phytovolatilisation, hydraulic control and more. Already in use are plants (and here willow, poplar and grass) for the degradation of petroleum products, aromatic hydrocarbons (BTEX), chlorinated solvents, explosives and cyanides. However, phytotoxicity and pollutant mass balances were rarely documented. Often, the success of the projects was not controlled, and only estimates can be made about the applicability and the potential of phytoremediation. This lack of experience about possibilities and limitations seems to be a hindrance for a broader use of these techniques.     

水稻花药培养技术及其育种应用的研究进展

从材料基因型、取材时期与预处理、培养基种类、激素配比、碳源和其他添加剂等方面综述了水稻花药培养技术的研究进展.大多研究表明,花培是稳定水稻亚种间籼粳杂交后代遗传性状的有效方法,但目前花培的株产率仍很低,在4％以下,且籼稻的株产率显著低于粳稻,主要原因是籼稻的基因亲和力低及其花药褐化和幼苗白化现象严重.同时,从改善培养条件(取材时期、预处理、培养基、激素、添加剂等)、建立花药离体培养体系、结合转基因和分子标记技术等方面提出了加快花药育种进程的建议.     

栽培条件对水稻镉积累的影响研究进展

综述了不同土壤、肥料与水分等生态栽培条件对水稻镉(Cd)积累的影响。认为土壤类型与土壤p H,有机肥与氮磷钾肥、硅肥、钙肥及其他微量元素肥,以及水分管理等均对水稻镉积累具有明显的影响;淹水是通过影响土壤的各种理化性质来影响土壤镉的生物有效性;合适的栽培方式能在保证水稻产量的同时,减少水稻对镉的吸收与积累。并提出了今后相关的研究方向。     

烤烟氯营养研究进展

氯元素既是烤烟必需的微量元素之一,对烤烟生长发育及产质量有重要影响,也是影响烟叶质量的主要指标之一。传统观点认为烤烟是忌氯作物,生产上禁施氯肥。但是据近年来相关报道部分烟叶产区由于氯含量过低而成为影响烟叶质量的重要限制因子,以往有关烟叶氯含量的控制所做的大量研究表明,在缺氯的烟区适当施用氯肥,能够促进烟叶生长发育,并且有助于改善烟叶品质。阐述了氯离子对烤烟的生理作用,对初烤烟叶质量的影响以及烤烟氯素吸收积累规律,同时对以往增施氯肥的研究进行了综述,并对今后烤烟氯素的研究做了展望。