【作者】 刘志刚；

【导师】 李萍萍；

【作者基本信息】 江苏大学 ， 农业生物环境与能源工程， 2014， 博士

【摘要】 有机基质栽培已经成为设施园艺中避免连作障碍的一种有效技术。但是对于基质的水分特性及其检测方法还少有研究,这就导致基质栽培中的水分灌溉尚达不到合理和精确的程度,影响作物生长及产量提高。如何能够精确地监测基质中的水分含量,优化基质栽培的水分灌溉量,并实现智能化节水灌溉,是基质栽培高产高效迫切需要解决的一个问题。针对存在的问题,本文从基质水分监测传感器的选择、基质湿润体变化特征到温室基质栽培的生菜根系与基质湿润体的匹配等方面进行了系统而深入的研究,并提出了基质栽培的灌溉控制策略、开发了智能灌溉控制系统。主要研究工作有：1)通过对现有土壤水分传感器的优缺点分析,根据设施基质栽培的特点选取EC-5电容传感器作为基质含水率的检测设备,分析了基质类型、基质温度、基质容重和基质电导率等因素对EC-5传感器检测基质含水率精度的影响,确定主要影响因素并提出了简单易行的传感器修正方法。通过对基质剖面含水率的动态变化监测以及对不同深度基质层含水率的变异性和相关性分析,采用聚类分析法确定EC-5传感器的布设位置。2)研究了滴灌情况下滴灌流量、滴灌历时、滴灌量和基质初始含水率对基质湿润体和基质水分分布的影响。结果表明：滴灌各基质的湿润体的形状近似于旋转抛物体,其水平入渗半径最大的地方不在基质表面,而是在基质表面下3-6cm处。滴灌流量、基质初始含水率和滴灌历时均相同时,基质湿润体积大小为T4(醋糟+泥炭25%+蛭石25%)>T3(醋糟+泥炭25%)>T2(醋糟+泥炭50%)>T1(T1醋糟)。相同灌溉量,不同滴灌流量情况下,滴灌流量为0.15L/h时基质水平入渗距离至少比0.5L/h的大23.3%,垂直入渗距离最多比0.5L/h的大5.5%,且形成的基质湿润体积较流量为0.5L/h大,滴箭8cm以下相同位置基质的平均含水率至少比0.5L/h的高20%。相同灌溉历时情况下,不同滴灌流量情况下,滴灌历时60min,滴灌流量为0.5L/h时基质水平入渗距离至少为0.15L/h的1.04倍,垂直入渗距离至少为0.15L/h的1.34倍,且形成的基质湿润体积较流量为0.15L/h大,各基质的最大基质含水率比滴灌流量为0.15L/h的高9%-13.5%。相同滴灌流量,不同灌溉量情况下,基质的垂直入渗距离至少比水平入渗距离大62%,滴灌历时为198min时,距滴箭水平方向3cm处基质含水率至少比滴灌历时为60min的高30%。相同滴灌历时,随基质初始含水率的增加,基质垂直入渗距离至少减小13%,水平入渗距离至少增加31%,基质表层下方含水率等值线愈加弯曲。3)研究了微喷灌情况下基质初始含水率和微喷灌量对基质垂直入渗距离和基质水分分布的影响。结果表明：各基质处理均出现中间层,约在垂直方向4-10cm范围内,基质含水率在该层变化较大；相同基质初始含水率,基质水分的垂直入渗距离随灌溉量的增加而增大,喷灌历时为30min时的中间层平均基质含水率至少比15min的大22%。相同灌溉量,随基质初始含水率的增加,复配基质T2,T3和T4水分垂向平均运移速率增加56%,而基质T1在低基质初始含水率时的水分垂向运移速率较大,比复配基质水分平均运移速率大58%,中间层平均基质含水率至少增加7.4%,但其基质含水率等值线密度则随基质初始含水率的增加而降低。4)采用无量纲分析法,建立了微灌情况下基质湿润体特征模型,并在此基础上建立了基质湿润体半经验模型,通过试验数据进行验证,结果表明,滴灌情况下,4种基质的水平入渗距离和垂直入渗距离的预测值与实际值之间相关系数R2均达0.8以上,回归估计标准误差RMSE和平均误差ME最大分别为1.06cm和1.18cm和-0.154和-0.53cm；微喷灌情况下,4种基质的垂直入渗距离的预测值与实际值之间相关系数R2均达0.9以上,RMSE和ME最大分别为1.06cm和1.3cm,表明该模型能较准确的模拟微灌情况下基质湿润体变化。5)分析了影响生菜根系生长和分布的主要因素。以积温作为定量发育进程的尺度,构建了预测生菜根长和根深的模拟模型,以积温和根深为自变量,建立了根区半径动态变化模型。结果表明：通过对不同采样期的生菜根长、根深和不同根深处的根区半径进行方差分析,最小的P值均大于0.05,没有显著差异性,可以忽略本实验所用栽培基质种类的影响；不同灌溉方式下,生菜根长密度主要集中在0-6cm基质层内,约占总根长密度70%以上。所建的生菜根长、根深和根区半径动态模型对滴灌和微喷灌生菜的根长、根深和根区半径的预测值与实际值之间回归估计标准误差RMSE和相对误差RE最大分别为290cm、0.81cm、0.63cm和15%、12%、13%,模型能较好的预测生菜营养生长阶段根系的生长情况。6)分析了影响灌溉控制的影响因素并进行蒸散量估算,提出了基于蒸散量、生菜根系与基质湿润体剖面面积重叠度的滴灌控制策略、匹配原则,以及基于蒸散量、生菜根深与基质垂直湿润锋的微喷灌控制策略。对设施基质栽培灌溉控制系统进行需求分析,提出系统设计原则,采用ZigBee网络技术设计了一种基于ZigBee技术的设施基质栽培智能灌溉控制系统,并进行了灌溉试验,达到优化控制目标。结合前文灌溉开始后基质湿润体变化预测,根据生菜定植后的生长时间对生菜根系变化的预测,采用本灌溉控制策略决策是否灌溉以及灌溉的量,以达到精确优化灌溉的目的。更多还原

【Abstract】 The organic matrix cultivation has become an effective technique to avoid continuous cropping obstacle in protected horticulture. But there is little research for the matrix moisture characteristic and its detecting method, this leads to the water irrigation in matrix is not reasonable and accurate, effects the crop growth and yield. How to monitor the moisture content in the matrix accurately and realize intelligent water-saving irrigation is an urgent problem to solve. In view of the existing problems, we deeply study the matrix moisture monitoring sensor, the matrix wetting body variation characteristics, the matching of the wetting body and the lettuce root, Put forward the irrigation control strategies in matrix cultivation and development of intelligent irrigation control system. The main research works are:1) Through the analysis of the existing soil moisture sensor,and features of facilities substrate cultivation,the article selected EC-5capacitive sensor to detect the moisture content of the substrate. Analysis the type of substrate, substrate temperature, substrate density and conductivity of the substrate effecting on detecting precision of EC-5moisture sensor, determine the main factors and proposes a simple correction method of sensor. Through the dynamic monitoring of moisture of cross-section substrate and the variability and correlation analysis of matrix moisture at different depths, the article uses cluster analysis to determine the final layout position of EC-5sensor.2) Study on the influence of irrigation flow, drip lasted, drip irrigation initial water content of the matrix on matrix wetting body and water distribution under drip irrigation. The results show that:the wetting body shape of the matrix is similar to the paraboloid of revolution under drip irrigation. The maximum radius of level infiltration is not on the substrate surface, but3-6cm under the surface of the matrix. The size of the wetting body is T4>T3>T2>T1when drip flow, matrix initial water content and drip duration are the same. The horizontal infiltration distance at0.15L/h is more23.3%than at0.5L/h at least,the vertical infiltration distance is more5.5%than at0.5L/h at most under the same irrigation amount and different drip flow. The horizontal infiltration distance at0.5L/h is1.04times of0.15L/h at at least, and the vertical infiltration distance is1.34times of0.15L/h at at least under the same irrigation duration (60min)and different drip flow, the maximum matrix moisture increased9%-13.5%. The vertical infiltration distance is more62%than the horizontal infiltration distance at least, and the matrix water content is increased30%under the same drip flow and different irrigation duration (60min and198min). The horizontal infiltration distance increased31%and the vertical infiltration distance decreased13%with the matrix initial water content increase under the same irrigation duration.3) This paper studies the effects of the initial moisture content of matrix and micro sprinkler irrigation amount on vertical infiltration distance and water distribution of matrix in micro-sprinkler case. The results showed that:each matrix treatment appear the middle layer in the vertical direction about4～10cm range,and the matrix moisture content changes larger in the layer. In the same matrix intial water content, the vertical infiltration distance increases with the amount of irrigation, the average matrix water content in the layer at the irrigation perod (30min) was more22%than at15min at least. In the same micro-sprinkler irrigation amount, the average vertical migration rate of T2,T3and T4increased56%with the increase of the matrix initial water content, but the vertical migration rate of T1was more56%than compound matrixs at the low matrix initial water content,but the matrix moisture content contour density decrease with the initial water content increase.4) The matrix characteristic value model and matrix wetting body semi empirical model were established using dimensionless analysis method. The results show that the correlation coefficient between the prediction value and the actual value of the horizontal infiltration distance and vertical infiltration distance for4kinds of matrixs were was more than0.8, the RMSE and the ME were were1.06cm,1.18cm and-0.154,-0.53cm for drip irrigation; The correlation coefficient between the prediction value and the actual value of the vertical infiltration distance for4kinds of matrixs were was more than0.9, the RMSE and the ME were were1.06cm and1.3cm for micro-irrigation; It show that the models have high accuracy for prediction the matrix wetting front.5) Analysis the factors of influence the root growth and distribution characteristics for lettuce. Models for lettuce root length, root growth and root zone were established using the accumulated temperature. The results show that the effects of matrix types can be ignored; Under different irrigation methods, lettuce root length density is mainly concentrated in the0-6cm matrix layer and accounting for more than70%of the total, and the microsprinkler irrigation is advisable under the high temperature season for lettuce cultivation with matrix. The RMSE and RE between predictive value and actual value for lettuce root length, root depth and root zone radius were290cm,0.81cm0.63cm and15%,12%,13%, The model can predict the root growth of lettuce well.6) According the requirement of the irrigation control system using in the matrix cultivation to present the design principle. Using visual studio as the software development tool, c#as the programming language, sqlserver as database, design a irrigation control system using in the matrix cultivation based on ZigBee technology, analysis of the factors influencing the irrigation control and estimation the evapotranspiration. Prent the matching principle and the drip irrigation strategy based on the evapotranspiration,the overlap of section area of lettuce root and wetting body, and the microspray irrigation strategy based on the evapotranspiration,the overlap of the lettuce root depth and matrix vertical wetting front, then start the comprehensive irrigation control.As a consequence, according the flow information to estimate the change of the matrix wetting body after irrigation began and the growth time after lettuce planting to estimate the changes of lettuce root. Using the preset irrigation control strategy to decision whether irrigation and irrigation quantity in order to achieve the purpose of accurate irrigation.更多还原