地下滴灌田间管网室内试验测试系统(简报)

针对地下滴灌管网中各灌水器出流量难以测量的问题,提出一种新的试验测试方法--称重测量法,可获得各灌水器的出流量.测试系统由称重传感器、压力变送器、数据采集系统和计算机及相关软件构成,可同时间接获得地下滴灌管网中各灌水器的出流量和直接测量出支管与毛管的沿程压力.而且还可实现自动监控、自动采集和存储测试数据的功能.实测结果表明:系统测试精度可满足试验要求.该测试系统操作简便,是室内试验研究地下滴灌田间管网水力要素变化规律的有效方法.     

面向土地精细平整的车载三维地形测量系统设计与实现

设计开发了一种基于全地形车（ATV）的农田三维地形快速采集系统,系统由ATV车辆、RTK-GPS、田间作业辅助导航装置、车载计算机和数据采集软件等部分组成。采用高精度RTK-GPS自动测量三维地形数据,车载计算机能实时记录三维地形数据,辅助平行作业导航装置能指引数据采集车辆在测区进行全区域覆盖测量,以提高农田三维地形数据采集质量和效率。田间实测试验表明,基于ATV的三维地形数据自动采集系统测量的三维地形与人工RTK-GPS测量的三维地形与具有很好的空间一致性,最大平均偏差3.54 cm,最大标准偏差2.48 cm,能够满足农田土地精细平整三维地形数据采集工作的需要。     

Die Erodibilität ausgewählter Böden der bayerischen Schichtstufenlandschaft

Erodibility of Selected Soils in the Bavarian Scarpland A laboratory rainfall simulator was used to determine the erodibility (K-factor of the USLE) of 6 soils. 3 of the soils were developed from mesozoic sediments (an Ochrept and an Udipsamment from sandstones, an Udorthent from shale), an Udalf and an Udorthent of loessial origin, and an Udorthent, that was developed from a silty-loamy cover. The measured K-values of the loessial soils agreed well with the calculated. But the calculated K-factors for the 3 Jurassic soils underestimated their erodibility. The erodibility of the silty-loamy soil was overestimated. It could be shown that the measured erodibilities agreed better with field data than the calculated.     

变量施肥电液比例控制系统的设计与实现

为了提高肥料的利用率,同时减少肥料浪费以及多余肥料对环境的不良影响,该文设计开发了一套以MC68HC908GP32单片机为中心的自动变量施肥控制系统。该系统通过RS-485总线接收上位机根据GPS、GIS 数据对应的流量信息,由单片机实时控制液压执行机构,变量输出田间不同位置的施肥量。通过对施肥机实验室静止试验和田间动态试验验证,变量控制可靠,作业效果良好,施肥控制精度小于4%。     

作物水胁迫声发射检测及视情灌溉系统的研究

研究和开发了利用声发射技术检测作物的水胁迫并视情实施自动灌溉的系统，以西红柿作物为目标在温室内进行了试验研究。结果表明：在一定程度范围内，作物受水胁迫时发出悲鸣的频次随作物水胁迫的程度的增加而增加，并与作物的蒸腾加速度有关；为避免作物受水胁迫的影响，可通过声发射传感器所获得的作物信息实现对作物视情灌溉和调节；使作物的蒸腾量和灌溉量达到平衡调节，力求使作物在最佳的土壤水环境下生长,提高水的利用率,改善作物果实品质。     

基于GSM的数字农业远程监控系统研究与应用

应用无线网络技术可实现农机作业过程和农田水利设施等的远程监控,为作物生长过程与产量、农业气象等信息的实时采集提供保障。探讨了基于GSM无线技术的数字农业远程测控系统组成结构,阐述了系统监控端软件的实现。在此基础上,采用自行研制的GSM远程通信控制器,开发了智能测产远程数据传输系统,并介绍了该系统的硬件组成和相应软件开发。在测产试验中对现场数据传输的实时性进行了测试,结果表明,GSM无线通信技术能满足农业远程监控的要求。     

THE APPLICATION OF MULTIVARIATE ANALYSIS TO SOIL STUDIES

Allocation of a profile to a predetermined group is normally made by the surveyor in the field but alternatively a computer can be programmed to process data and make the allocation. Differences arising from these procedures may be due to differences in either the information used by computer and surveyor or the rules used to analyse the data. There is a third method, in which the surveyor, using the same data as the computer, provides a link between the other two. Comparison, in general terms, of possible results from these three methods is supported by a study on profiles from the Riverina, N.S.W. Using data for a standard set of variables and allocating into one of three groups, misallocation of 4 per cent of a test sample of forty-six profiles resulted from both the computer method and the surveyor in the laboratory as compared with the surveyor's allocation of the same profiles on morphological properties in the field. This concurrence between the surveyor and the computer method allows the skill of the surveyor to be extended by way of the computer to technicians.     

Sample accountability quality assurance for the "Integrated Air Cancer Project" research program of the U.S. Environmental Protection Agency

A sample accountability quality assurance (QA) program is described for a field and laboratory research effort which resulted in collection of approximately 2000 samples for analysis by several EPA and contractor laboratories. A QA program was specifically developed for this research program to include sample transfer from collection site to storage maintenance, record development, transfer to researchers, and sample tracking at all stages. A sample identification system and sample custody records are described for field and laboratory application. The functions of a sample coordinator are also described as relating to sample custody, coordination of sample analysis with researchers, and development of computer record files to facilitate research and sample tracking.     

A mathematical model for evaluating the effect of wind on downward-spraying rainfall simulators

Rainfall simulators are used to study a variety of different processes (e.g., water erosion, infiltration, overland flow, irrigation, movement of agrochemicals, etc.). Wind affects field experiments that make use of rainfall simulators. Water-drop trajectories and velocities are altered, affecting water application and kinetic energy distributions.In this study, a three-dimensional numerical model was developed from the movement of individual drops after their release from the nozzle of a downward-spraying rainfall simulator. Drag forces, wind and gravity affect the original momentum of a single drop. Water application and kinetic energy were estimated from the coupling of a hydrodynamic model for drop movement, a drop generator representing a single full-cone spray nozzle, and an appropriate interception algorithm at the soil surface.The mathematical model should facilitate the selection of single full-cone spray nozzles and the size and configuration of the spray area for rainfall simulation in order to achieve high application uniformity values on the plot area. It can contribute to the adequate choice of nozzles as well as operating conditions necessary for laboratory and field purposes. Laboratory and field experiments were conducted to evaluate the adequacy of the proposed methodology.     

基于GPRS和WEB的温室环境信息采集系统的实现

针对农业对象具有的多样性、多变性、以及偏僻分散等特点,提出了一种基于GPRS和WEB技术的远程数据采集和信息发布系统方案。首先,通过RS—485总线与数字传感器连接,并与PC监控计算机构成温室现场监控系统;其次,通过GPRS无线通讯技术建立现场监控系统与互联网的连接,将实时采集信息发送到WEB数据服务器。系统软件核心技术系MS VB.NET和ASP.NET 开发而成,构建了基于B/S(Browser/Server)的“瘦客户”模式,只要通过浏览器不仅可实时浏览监测数据,而且能进行历史数据的查询。该系统的实现为农业网络信息通讯中“最后一公里”瓶颈问题提供了一种便捷的解决方案。     

Pesticide Leaching from Agricultural Fields with Ridges and Furrows

In the evaluation of the risk of pesticide leaching to groundwater, the soil surface is usually assumed to be level, although important crops like potato are grown on ridges. A fraction of the water from rainfall and sprinkler irrigation may flow along the soil surface from the ridges to the furrows, thus bringing about an extra load of water and pesticide on the furrow soil. A survey of the literature reveals that surface-runoff from ridges to furrows is a well-known phenomenon but that hardly any data are available on the quantities of water and pesticide involved. On the basis of a field experiment with additional sprinkler irrigation, computer simulations were carried out with the Pesticide Emission Assessment at Regional and Local scales model for separate ridge and furrow systems in a humic sandy potato field. Breakthrough curves of bromide ion (as a tracer for water flow) and carbofuran (as example pesticide) were calculated for 1-m depth in the field. Bromide ion leached comparatively fast from the furrow system, while leaching from the ridge system was slower showing a maximum concentration of about half of that for the furrow system. Carbofuran breakthrough from the furrow system began about a month after application and increased steadily to substantial concentrations. Because the transport time of carbofuran in the ridge soil was much longer, no breakthrough occurred in the growing season. The maximum concentration of carbofuran leaching from the ridge-furrow field was computed to be a factor of six times as high as that computed for the corresponding level field. The study shows that the risk of leaching of pesticides via the furrow soil can be substantially higher than that via the corresponding level field soil.     

农地耕层与犁底层土壤入渗性能的连续测量方法

研究农田土壤入渗性能对于了解铧式犁耕作对土壤水力性能的影响、指导农地耕作方式决策、农田灌溉、改善农地生态环境具有重要意义。该文提出了一种农耕地耕层与犁底层土壤入渗能力连续测量方法以及相应的计算模型。采用恒定流量向地表供水,由供水在地表湿润面积随时间的变化过程估计地表耕层土壤初期很高的入渗性能,由产流后供水流量与产流流量之差计算相对较低的土壤入渗性能及犁底层土壤入渗性能。并进行了室内模拟试验,结果表明该方法可连续测量农地耕层与犁底层的入渗过程。采用入渗量和供水量对比的方法进行误差分析,相对误差为5.75%,说明该方法具有较高精度。该方法省时、省水便于野外应用,为今后的进一步研究提供手段。     

槽式人工模拟降雨机的工作原理与特性

利用人工模拟降雨，可以进行各种下垫面条件下土壤侵蚀与水土保持实验研究，大大缩短了试验研究周期，已成为室内与野外试验的重要技术手段，是获取土壤侵蚀、水土保持效益、土壤侵蚀模型等相关研究数据的有效途径。在详细论述人工模拟降雨机的基本要求和类型的基础上，重点论述了槽式人工模拟降雨机的结构、工作原理及其优缺点，旨在促进我国人工模拟降雨机研制的步伐，为土壤侵蚀与水土保持相关实验研究提供参考。     

蒸发比法能量强制闭合及其对稻田蒸散量估算精度的影响

为探求节水灌溉稻田蒸发比(潜热通量与有效能量的比值,EF)变化特征及能量平衡闭合情况对稻田蒸散量测算的影响,该研究采用涡度相关系统,监测了2014-2016年节水灌溉稻田湍流通量过程,分析了稻田蒸发比的不同时间尺度的变化特征,对比了能量强制闭合前后湍流通量的比例与过程变化。结果表明,节水灌溉稻田EF与旱作物不同,小时尺度EF先减小后增加,在10:00-12:00时段的数值最为稳定。水稻全生育期EF均在0.7～1.0之间变化,均值约0.93,潜热蒸散是稻田主要的能量消耗项。能量强制闭合修正后湍流通量明显增加,日峰值差异最大,昼夜交替时,稻田能量平衡处于过闭合状态;能量强制闭合后不同时间尺度上的蒸散量都明显增加,能量强制闭合是涡度相关法准确计算蒸散量的前提。研究结果可为稻田蒸散量准确测算与蒸散模型扩展研究提供重要的数据支撑与方法。     

聚丙烯酰胺施用对铵态氮地表径流迁移的影响及解析模拟

地表氮素迁移至径流的水平对氮素流失有重要影响。该研究在人工模拟降雨条件下,主要考察高分子有机化合物聚丙烯酰胺（PAM）施用对铵态氮地表径流迁移效应。试验结果表明,PAM的施用降低了径流运移氮素的能力,表现为铵态氮初始流失浓度极大降低,且氮素流失过程更趋平稳。基于土壤混合层理论和氮素平衡原理建立了PAM施用下铵态氮地表迁移不完全混合模型,并求得了解析解,证实了地表铵态氮径流迁移符合指数型衰减过程,模拟结果与实测值拟合较好。     

基层水土保持档案系统的建设

 建立基层水土保持档案系统,是国家生态监测网站建设的重要内容。在福建省南安市,以小流域为单元对基层水土保持档案系统建设进行了研究。利用信息规范化技术采集数据,形成档案库、计算机数据库及其查询系统,并利用现有网络基础,实现数据的流通、汇总,实现基层野外作业的数据与各级部门数据实时互动管理。从基层入手,由小到大,可形成全国水土保持信息档案库。     

少免耕播种机牵引阻力远程监测系统

针对少免耕播种机牵引阻力的监测,该文提出了一种能够实时采集信号、无线传输数据、现场移动监测、远程同步监测的少免耕播种机牵引阻力监测系统。该系统通过在3点悬挂杆铰接处安装2维轴销测力传感器实现对其受力情况的实时检测。采用无线传感网络技术(wireless sensor network,WSN)实现传感器信号采集和数据短距离无线传输。采用嵌入式技术开发无线数据监测移动终端,实现牵引阻力的现场监测以及数据转发。利用Visual C++开发的远程监测软件,在远程计算机上实现牵引阻力的动态监测、实时显示、在线分析和批量存储。经计量,该系统模拟量检测最大误差为4 mV,线性度为0.04%。田间试验表明:系统实现了少免耕播种机牵引阻力的现场移动监测以及远程同步监测,系统使用方便并降低了田间测试的复杂程度。     

大型喷杆悬架系统测试平台设计与评价方法研究

目前喷杆悬架系统的性能田间测试受到测试地形、土壤属性、驾驶熟练度等随机因素的影响,需要有一种定量评估喷杆悬架性能的试验装置与方法。该文开发了一套喷杆悬架性能室内测试平台,包括一个多自由度底盘运动模拟平台、地形起伏模拟平台及基于NI PXI的同步触发测控系统。为准确模拟实际的工作环境,在喷雾机作业现场采集了底盘的运动姿态信号和喷杆两侧地形高程数据,并在室内进行精确复现。考虑测试时传感器安装位置和不同喷杆理想作业高度的差异,对传统的Hockley指数进行了修正,并使用标准差、变异系数、修正的Hockley指数等3种指标一起来描述喷杆悬架系统的性能,弥补了各自的局限性。通过喷杆悬架测试平台先后对28 m喷杆在无悬架、被动悬架、主动悬架等不同工况下进行了测试,多组重复测试结果的变异系数小于5.91%,无悬架时喷杆的Hockley指数为21.60,使用被动悬架时喷杆的Hockley指数为68.37,使用主动倾角控制系统时喷杆的Hockley指数为89.18,使用主动喷臂控制系统时的Hockley指数为92.83,表明测试平台与评价指标对不同悬架系统有较好的区分度和适用性。该文设计的测试平台可为喷杆悬架性能参数的限定和评价方法的完善提供参考。     

格网化小麦生长模拟预测系统设计与实现

利用作物生长模型模拟小麦区域生产力,分析气候变化对农业生产的影响是研究粮食安全的热点问题之一。拥有操作方便、计算快速特点的小麦区域生产力模拟系统,可有效提高作物生长模型区域应用能力。该研究在分解小麦生长模型WheatGrow算法基础上,利用Python语言构建了格网化小麦生长模型,实现了基于空间格网数据的小麦区域生产力模拟。验证试验结果表明:模拟产量的均方根误差为1 070 kg/hm~2,标准均方根误差小于20%,系统所集成的WheatGrow模型具有较好的预测性;同时,结合格网数据分块构建区域模拟的并行计算策略,优化了区域模拟的性能。在此基础上,采用GIS组件式开发模式,在.NET平台下开发格网化小麦生长模拟预测系统,实现作物生长模型与GIS耦合,为研究区域小麦产量潜力,评估气候变化对小麦生长影响,制定农业决策提供软件工具。     

农林院校计算机实验室管理模式和方法的研究

为了提高农林院校计算机实验室的管理水平,必须从理论上对实验室的管理模式进行深入研究,从而指导和应用于实践中去。分析了国内外实验室管理的现状、趋势以及农林院校计算机实验室面临的主要问题,阐述了采用各种管理模式的利弊,探索了管理好计算机实验室的方法和对策,并提出了农林高校计算机实验室必须建立以农林为特色的各类实验分室,实现网络化管理,同时要面向农村、面向基层、面向社会培养农林业计算机人才,为建设我国社会主义新农村做出应有的贡献。