Closed-loop drip irrigation control using a hybrid wireless sensor and actuator network

In this research, a closed-loop drip irrigation control hybrid wireless sensor and actuator network (HWSAN) prototype were developed and deployed in a crop field for soil property precise measurement and precision irrigation in accordance with the measured soil property. The HWSAN was composed of a wireless sensor and actuator network (WSAN) used for in-field soil property monitoring and irrigation control and a laboratory supervising system. The WSAN included ten sensor nodes, five irrigation control nodes...     

云计算农田会商平台规划和设计

面向西北旱区农业,基于云计算、大数据和物联网技术的集成应用会商平台,利用卫星、无人机和地面传感网等多遥感平台,对耕地平整、水肥药精准作业装备进行作业调度,形成精准作业调度、遥感的空间决策支持、多源农情信息视频会商、以及农情遥感信息适时发布系统于一体的综合性、业务化的会商服务平台.该平台提供专家会商、水肥管理、病害诊断防治、旱情预测预报和农业遥感信息适时发布等服务.     

基于ETLB-DEEC的精细农业无线传感器网络研究

无线传感器网络技术应用于精细农业信息获取与管理已成为一种趋势和必然,针对WSN在大规模农田种植监测领域中所面临的监测面积大、监测时间长、低功耗要求、地势复杂以及作物多样等问题,深入研究基于DEEC的等边三角形节点部署的负载均衡成簇协议ETLB-DEEC(Equilateral Triangle Load Balancing-DEEC),采用等边三角形网格节点部署方式与网络分区,提出"孤儿节点"和"收容节点"的概念.在此基础上,设计一种面向基站最短路径簇间多跳寻优机制,可找寻多条最短路径协议.仿真结果表明,改进的协议具备高效节省传感器节点数、实现全局网络负载均衡,提高网络能量利用率,延长WSN整体生命周期等功能和特点.     

三角形迷宫流道滴灌灌水器结构参数及水力特性研究

以滴灌灌水器三角形迷宫流道结构为研究单元,利用均匀设计方法,结合计算流体动力学软件Fluent6.2对流道内部流体的流动进行了数值模拟,通过多元回归计算,获得流道各结构参数与流量系数和流态指数的量化关系。分析这一量化关系表明,流道转角与流量成负相关,与流态指数成正相关;流道宽与流量成正相关,与流态指数成负相关;齿高与流量成负相关,与流态指数成正相关。同时分析了灌水器内部流道的水力性能和流场特性,为三角形迷宫流道滴灌灌水器的研发提供了相应的理论依据。     

黑龙江黑河市小麦和大豆的灌溉计划

以黑河市典型农作物大豆和小麦为研究对象,利用气象数据和相关研究成果,计算了黑河地区大豆和小麦的需水规律和需水量,并和降水分布和有效降水量进行对比。研究发现在小麦生长阶段内,小麦需水量和降水量基本同步,但是6月-7月份亏水量约72 mm。在大豆整个生育期内,各月有效降水量均不能满足大豆的需水量,6月份缺水量最大为88 mm,生育期内共缺水量182 mm。考虑到当地矮杆作物灌水技术一般采用喷灌,建议灌水定额采用40 mm,小麦需在6月份喷灌一次,大豆在整个生育期内喷灌4~5次,以实现小麦和大豆的高产稳产。     

甘肃景电灌区次生盐化土壤的性质及其发生机理

本文对甘肃景电灌区次生盐化土壤的理化性质进行了研究 .该区次生盐渍化土壤主要为硫酸盐氯化物和氯化物硫酸盐型 ,水溶性钠离子在阳离子中占绝对优势 .土壤通体碳酸钙含量很高 ,并有少量的石膏 .钠离子饱和度很高 ,具有钠质特性或钠质化现象 ,盐化与钠质化同时进行 .在此基础上对次生盐渍化的机理和改良进行了讨论     

Time-dependent soil-water distribution under a circular trickle source

Soil-water distribution in homogeneous soil profiles of Yolo clay loam and Yolo sand (Typic xerorthents) irrigated from a circular source of water, was measured several times after the initiation of irrigation. The effect of trickle discharge rates and soil type on the locations of the wetting front and soil-water distribution was considered. Soil-water tension and hydraulic conductivity, as functions of soil-water content, were also measured. The theories of time-dependent, linearized infiltration from a circular source and a finite-element solution of the two-dimensional transient soil-water equation were compared with the experimental results. In general, for both soils the computer horizontal and vertical advances of the wetting front were closely related to those observed. With both theories, a better prediction of the wetting front position for the clay loam soil than for the sandy soil is shown. The calculated and measured horizontal vertical advances did not agree over long periods of time. With the linearized solution, overestimated and underestimated vertical advances for the clay and sandy soils, respectively, were shown. The finite-element model approximate in a better way the vertical advances than the linearized solution, while an opposite tendency for the horizontal advances indicated, especially in sandy soil.Notation k constant (dK/d) - K hydraulic conductivity - K ₀ saturated hydraulic conductivity - J ₀,J ₁ Bessel functions of the first kind - h soil water tension - q Q/r ₀ ² - Q discharge rate - r cylindrical coordinate; also horizontal distance in soil surface - R dimensionless quantity forr - r ₀ constant pond radius - R ₀ dimensionless quantity forr ₀ - t time - T dimensionless quantity fort - x, y Cartesian coordinates - z vertical coordinate; also vertical distance along thez axis chosen positively downward - Z dimensionless quantity forz - empirical soil characteristic constant - dummy variable of integration - volumetric soil water content - matrix flux potential - dimensionless quantity for      

谈长龙灌区渠道整治措施

本文根据江西省赣州市中型灌区节水配套改造项目原则和要求,针对兴国县长龙灌区渠系及其建筑物目前存在的问题,分别提出了相应的整治措施,为确保灌区渠道输水安全,进一步提高灌区水的利用率和灌溉保证率,从设计方法上提供有益的经验.     

论郑州市花园口灌区发展引黄供水事业的制约瓶颈及良策

花园口引黄灌区是郑州市的一座中型灌区,成立较早,灌区建设早期主要承担农业灌溉任务,随着城市化进程的加快,灌区同时承担龙湖调蓄池、三河一渠的供水任务。笔者通过研究近几年灌区发展状况,提出了七个制约灌区良性发展的问题,并针对问题,提出解决对策。     

膜缝沟灌技术要素试验研究

试验选择了膜缝宽度、土壤初始含水率、土壤密度及水深四个因素,通过四因素-三水平的正交试验设计方案,采用极差分析方法,以入渗速率和水平与垂向湿润锋推进距离的比值为评价指标,得出了适宜室内试验条件下膜缝沟灌较为合理的技术要素组合,即当初始含水率为9%、土壤密度为1.45g/cm3时,最优膜缝宽度为5 cm,最佳水深为12 cm。这对提高田间水利用率和灌溉水利用率,有一定的理论和实践意义。