基于AT89S51的蔬菜大棚温控系统设计

以AT89S51单片机为控制核心,以数字温度传感器DS18B20为测温元件,采集温室内的温度信息。通过对当前温室环境的现状进行分析,对温室温度参数进行调节,以达到栽培作物生长发育的需要,为作物的生长提供最适宜的温度环境,大幅提高作物的产量和质量。     

基于经济最优目标的温室环境控制策略

将温室作物整个生长季节分为营养生长阶段和生殖生长阶段。在营养生长阶段,以温度优先为控制策略,即以温度为主控参数,根据温室内加温和降温的幅度等级来选择相应的执行机构,实现温室内作物栽培的环境参数控制要求。在作物生殖生长阶段,综合控制成本模型、温室环境的预测调控模型和作物生长模型,以温室产出与投入比最大为温室环境控制目标进行决策,为温室内作物生长提供经济适宜的环境参数和生长条件。以黄瓜为栽培对象,进行了温室周年生产。实践表明,按经济最优目标的控制策略来实现温室环境控制,既保证了作物正常生长的需要,又兼顾了经济成本。     

温室环境对番茄干重影响的参数优化

番茄是设施蔬菜栽培的主要作物之一.为此,以温室番茄的干重作为温室环境控制的目标进行优化,为温室作物生长提供经济适宜的环境参数和生长条件;重点研究了温室内番茄生长的环境参数(温度、相对湿度、光照强度)对番茄干重的影响规律和温室环境系统最佳参数.试验结果表明,影响试验指标的主要因素是温度、相对湿度、光照强度,其较优组合是温度为31℃、相对湿度为69%、光照强度为71klx.     

基于PLC与WinCC组态软件的智能温室控制系统设计

对温室环境中温度、湿度、光照、CO2浓度等环境因子进行调控是实现设施作物生产高产、优质、高效的关键。以WinCC组态软件为上位机编程软件,以PLC为控制器,设计一种基于PLC的智能温室控制系统。该系统人机界面友好,性能稳定可靠,性价比高,能很好地实现对智能温室环境因子的自动控制,满足温室作物生长环境控制要求。     

基于经济最优目标的温室黄瓜试验研究

黄瓜是设施蔬菜栽培的主要作物之一。为此,以黄瓜温室产出与投入比的最大值作为温室环境控制的目标进行决策,为温室作物生长提供经济适宜的环境参数和生长条件。同时,重点研究了温室内黄瓜生长的环境参数（温度、相对湿度、光照强度）对成本的影响规律和温室环境系统最佳参数。试验结果表明,影响试验指标的主要因素是温度,试验因素主次排列为温度、相对湿度、光照强度。其较优组合是温度为31℃、相对湿度为85％、光照强度为16klx。     

温室环境自动控制系统的研究

该文通过对作物生长环境因素的剖的,确定了蔬菜作物最佳生长发育的环境条件,并以引进的意大利玻璃温室为研究对象,设计了以８０３１单片机为核心的温室内温度环境的闭环控制系统。     

单栋塑料温室内多因子综合CFD稳态模拟分析

为分析单栋塑料温室内的综合环境:气流场、温度场、湿度场、CO2浓度场,建立了包括温室内外空间、室内作物和土壤层等的温室环境几何模型。将温室内的湿空气看作水蒸气、CO2和干空气的混合气体,在分析温室中太阳辐射、作物与环境的质热交换,动量及质能传递过程的基础上,对单栋塑料温室内的环境因子进行了稳态模拟。温室内热辐射传递过程采用蒙特卡罗法模拟方法;将室内作物简化为连续固体换热模型,采用剪应力输运模型(SST)表述温室内的空气紊流。结果显示:温室通风对温度、湿度和CO2分布的影响很大,温室内部上风向温度低,湿度小,同时CO2浓度也不高;温室下风向作物冠层的环境未达到优化状态;模型的预测值低于实测值,但变化规律相似,温度、湿度、CO2含量的预测相对误差分别低于8%、6%和7%。     

玻璃温室自然通风热环境时空分布数值模

温室内温度的时空分布及变化与外界气候环境之间有较强的耦合性.以Venlo型两连栋空玻璃温室为研究对象,基于计算流体动力学(CFD)技术,应用离散坐标(DO)辐射模型对温室内温度时空分布及变化进行了3-D稳态数值模拟与试验验证.结果表明:白天各时刻空温室内平均温度的模拟值与实测值吻合良好,最大相对误差为11.3%,平均相对误差为7.6%;温室内温度的空间分布梯度明显,作物区温度分布比较均匀,约在28.5～28.8℃左右.DO辐射模型模拟太阳辐射对玻璃温室内热环境的影响是可行的.     

荷兰温室环境控制系统的发展

温室中的环境指的是温室中作物在地面以上的生长空间。温室中的环境由许多个因子组成,诸如光、温度、相对湿度、二氧化碳浓度等是其中较为重要的几个。种植者可以利用农场管理系统对上述因子进行人为的影响,即环境控制,以给作物提供一个最佳的温室内生长条件。温室环境控制的方法这些年在荷兰发展得非常快,本文将就这些发展变化及其未来的发展趋势做一些简要的介绍。     

农业温室大棚智能环境监测系统设计

环境控制对于提高温室大棚的利用效率、使之利于作物生长实现增产增收具有重要意义。本课题设计的温室大棚环境监测系统,采用先进的温湿度传感器采集温湿度信号,以单片机为硬件核心,采用基于专家控制系统的智能控制器对数据进行分析和处理,对大棚内的环境包括温度和湿度进行实时监测并做出相应控制指令。     

Recent changes in the climatic yield potential of various crops in Europe

Recent changes in the simulated potential crop yield and biomass production caused by changes in the temperature and global radiation patterns are examined, using the Crop Growth Monitoring System. The investigated crops are winter wheat, spring barley, maize, winter rapeseed, potato, sugar beet, pulses and sunflower. The period considered is 1976-2005. The research was executed at NUTS2 level. Maize and sugar beet were the crops least affected by changing temperature and global radiation patterns. For the other crops the simulated potential yield remained stable in the majority of regions, while decreasing trends in simulated potential yields prevailed in the remaining regions. The changes appear in a geographical pattern. In Italy and southern central Europe, temperature and radiation change effects are more severe than elsewhere, in these areas potential crop yields of more than three crops significantly decreased. In the UK and some regions in northern Europe the yield potential of various crops increased.In a next step the national yield statistics were analyzed. For a large majority of the countries the yield increases of wheat, barley and to a lesser extent rapeseed are leveling off. Several explanations could be given, however, as the simulated yield potential for these crops decreased in various regions, the changing temperature and radiation patterns may also contribute to the diminishing yield increases or to the stagnation. In more than 50% of the investigated countries the maize, potato and sugar beet yields continue to increase. This can be attributed to improving production techniques, new crop varieties, sometimes in combination with an improving climatic potential. In some regions in northern Europe, yields continue to increase.     

作物生长多传感信息检测系统设计与应

简述了作物生长多传感信息检测系统的硬件平台及实现.光箱系统采用卤素灯和D65型标准光源两组独立可调的均匀光照系统,结合温湿度控制装置,可以实现对多种作物生长环境的模拟.信息采集系统集成了包括光谱、多光谱图像、冠层温度、冠层光照及环境温湿度等多传感信息探测器,可以充分利用多种信息对作物生长信息进行监测.应用该系统就油菜氮素和水分的光谱、多光谱图像特征及光照对检测的影响进行了研究,结果表明:该系统能够克服环境因素的影响,能够利用多传感信息对作物营养进行较准确的定量分析,其中,油菜氮素光谱特征模型的相关系数达到0.92,均方根误差为0.53.     

低温弱光对典型大棚作物生长影响的试验研究

【目的】分析低温弱光逆境典型大棚作物(辣椒、茄子、黄瓜)生长发育的影响及不同作物对低温弱光逆境响应程度。【方法】对典型大棚作物黄瓜、茄子及辣椒控制不同的光照和温度,观测其株高、茎粗、作物叶面积以及叶绿素质量浓度。【结果】作物对逆境的响应主要表现为生长被抑制与外形差异上,作物的株高、茎粗增长量均有降低,逆境处理时间越长,抑制作用越明显,辣椒的茎粗增长量受抑制的程度明显大于茄子。随着处理时间的延长,茄子与黄瓜的叶面积增长量降低,而辣椒叶面积增长量降低较少。在0～5 d叶绿素质量浓度比对照显著降低;随处理时间延长,作物对逆环境的适应,叶绿素质量浓度基本维持稳定。【结论】低温弱光下作物的株高、茎粗增长量降低,不同作物生长量受低温弱光的抑制程度不同;作物叶片中叶绿素的质量浓度前期显著降低后逐步趋于稳定。     

Effects of rising atmospheric CO2 on crop evapotranspiration in a Mediterranean area

In the assessment of plant response to the climate changes, the effects of CO₂ increase in the atmosphere and the subsequent rise of temperatures must be taken into account for their effects on crop physiology. In Mediterranean areas, a decrease of water availability and a more frequent occurrence of drought periods are expected. The objective of this study was to assess the impact of elevated CO₂ concentration and high temperature on reference evapotranspiration (ETo) and crop evapotranspiration (ETc) in the Mediterranean areas. The Penman-Monteith equation was used to simulate the future changes of reference evapotranspiration (ETo) by the recalibration of the canopy resistance parameter. Besides, crop coefficients (Kc) were adjusted according to the future climate trend. Then the modified empirical model (ETc = ETo × Kc) was applied providing an effective quantification of the climate change impact on water use of irrigated crops grown in Mediterranean areas. In the studied area, water use assessment was carried out for the period from 1961 to 2006 (measured data) and for a period from 2071 until 2100 (simulated data), showing a future climatic scenario. Water and irrigation use of crops will change as a function of climate changes, thermal needs of single crops and time of the year when they grow. Climate simulation model foresees the tendency for a significant increase of temperatures and a decrease of total year rainfall with a change of their distribution. The temperature increase and the concomitant expected rainfall decrease lead to a rise of year potential water deficit. About the autumn-spring crops, as wheat, a further increase of water deficit, is not expected. On the contrary, for spring-summer crops as tomato, a significant increase of water deficit and thus of irrigation need, is foreseen. Actually, for crops growing in that period of the year, the substantial rise of evapotranspiration demand cannot be compensated by crop cycle reduction and partial stomatal closure.     

CFD数值模拟技术在温室环境因子调控中的应用

为了给作物提供适宜的生长环境,使作物免受外部气候条件的影响和虫害的入侵,控制温室内部的微环境十分重要。温室内部的微环境包括温度、湿度和通风速率等环境因子,对作物生长起着至关重要的作用。计算流体力学（CFD）作为一种数值模拟仿真技术,近年来已经广泛用于温室内微环境的模拟,利用CFD对温室内微环境进行模拟,实现温室内流场分布的可视化,有利于优化和改善环境调控措施。讨论了近年来国内外有关CFD在温室通风降温中的研究概况,介绍其在温室微环境模拟中的发展现状、面临的挑战及未来的应用前景。      

Canopy-air temperature of crops grown under different irrigation regimes in a temperate humid climate

Summary Canopy temperatures of wheat, barley, rape and perennial rye grass crops, grown under temperate humid climatic conditions at different irrigation regimes were measured during two growing seasons, 1986 and 1987, by determining the emission of radiation in the wavelength interval 8<<14 m. Global radiation, net radiation, air temperature, relative humidity and wind speed were measured simultaneously. The canopy temperature of the crops either fully irrigated or under water stress fluctuated up to 6 °C within a few minutes in response to rapid changes in global radiation. At high level of global radiation (800–1000 W m^–2) canopy-air temperature differences up to 8 °C were measured whereas at low level of global radiation (100–200 W m^–2) canopy-air temperature differences were found to approach zero or become negative even at severe crop water stress. Canopy temperature differences between water stressed and fully irrigated crops up to 6 °C were measured under conditions of high evaporative demand whereas under conditions of low evaporative demand canopy temperature differences between water stressed and fully irrigated crops approached zero even at severe crop water stress. For each crop the lower base line, i.e. the relationship between canopy-air temperature difference and vapor pressure deficit for a fully irrigated crop, was estimated by linear regression. In most cases a poor correlation was obtained which is attributed to considerable temporal variability in global radiation and wind speed and to the narrow range of prevailing values of vapor pressure deficit. However, from the base line for rape and barley it was possible to calculate apparent values of the aerodynamic resistance and the crop resistance which were of the same order of magnitude as those found for other crops by using this method under more arid climatic conditions.     

Infrared canopy temperature of early-ripening peach trees under postharvest deficit irrigation

Canopy temperature measurements with infrared thermometry have been extensively studied as a means of assessing plant water status for field and row crops but not for fruit trees such as peaches. Like in many regions of the world, the lack of water is beginning to impact production of tree fruit such as peaches in the San Joaquin Valley of California. This is an area where irrigation is the only source of water for agricultural crops in the summer growing season. A two-year field study was conducted to assess plant water stress using infrared canopy temperature measurements and to examine its feasibility for managing postharvest deficit irrigation of peach trees. Twelve infrared temperature sensors were installed in a mature peach orchard which received four irrigation treatments: furrow and subsurface drip irrigation with or without postharvest water stress. During the two-year period, measured midday canopy to air temperature differences in the water-stressed postharvest deficit irrigation treatments were in the 5-7 °C range, which were consistently higher than the 1.4-2 °C range found in the non-water-stressed control treatments. A reasonable correlation (R² = 0.67-0.70) was obtained between stem water potential and the canopy to air temperature difference, indicating the possibility of using the canopy temperature to trigger irrigation events. Crop water stress index (CWSI) was estimated and consistently higher CWSI values were found in the deficit irrigation than in the control treatments. Results of yield and fruit quality assessments were consistent with the literature when deficit irrigation was deployed.     

保护性耕作条件下棵间蒸发量模型初探

为计算保护性耕作条件下农田棵间蒸发量,以一年两熟地区保护性耕作体系试验数据为基础,进行了以叶面积指数、地表秸秆覆盖率、地温比值、地表含水量等参数为自变量,日棵间蒸发量为因变量的4种回归分析.结果表明,影响日棵间蒸发因素强弱顺序依次是地温比值、地表含水量、叶面积指数及地表秸秆覆盖率,并建立了一年两熟地区保护性耕作条件下的蒸发积分模型.     

基于VB的温室温湿度实时监测上位机系统设计

研究并设计了一种基于VB的温室温湿度实时监测上位机系统。该系统能实现对现场采集的温湿度数据进行实时监测，并针对不同的作物，当环境温湿度参数越限时，启动声音报警，以便管理员介入进行自动或手动调控。提供温室作物最佳的温湿度生长环境，提高温室的自动化程度和生产效率。该系统应用软件工程的设计思想，以Microsoft Visual Basic 6.0为开发环境，Microsoft Access为后台数据库，采用模块化的设计方法，利用面向对象、数据库等技术完成系统数据的实时显示、信息和数据的存储、历史数据查询、统计分析、打印和异常报警等功能，实现了上位机系统的监测任务。介绍了系统的总体设计和各功能模块的设计，说明了该系统的主要功能，并给出了系统的运行界面和部分代码，在系统和数据库安全方面也采取了一定措施。