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1.
刘兵兵  魏建新 《南方农机》2022,(14):136-140
激光雷达是一种新兴的遥感技术,利用其可以获取高精度的森林冠层高度。本研究概述了现有的各种测量森林冠层高度的技术手段,然后利用塞罕坝机械林场的无人机激光雷达数据,对30 m空间分辨率的全球森林冠层高度产品(简称GFCH)进行了验证。结果表明,该产品与激光雷达获取的冠层高度相关性较弱(R2=0.24),且该产品精度偏低(RMSE=5.58 m),这主要与反演该产品时输入模型的数据质量有关。  相似文献   

2.
孙泉  耿磊  赵奇慧  杨佳昊  吕平  李莉 《农业机械学报》2022,53(S1):270-276,308
为研究温室内番茄冠层作物水分胁迫指数(CWSI)问题,通过布设多参数传感器,实时获取温室内外各环境参数。利用灰度关联分析,计算各环境参数与番茄冠层CWSI的关联度,根据关联度对环境参数进行排序,同时考虑对模型精度的影响,最终从9个环境参数中选取7个作为模型输入,建立基于LightGBM的温室番茄冠层CWSI预测模型。结合贝叶斯算法优化其中的关键参数,将模型预测结果与通过Jones经验公式计算出的CWSI做相关性分析,在相同的运算环境下,分别与GBRT和SVR模型对比。试验结果表明,基于贝叶斯优化LightGBM模型的决定系数(R2)、平均绝对误差(MAE)、均方根误差(RMSE)和运算时间分别为0.9601、0.0218、0.0314和0.0518s,与GBRT和SVR模型相比,其R2分别提高2.14%和14.05%,MAE分别降低0.0093和0.0612,RMSE分别降低0.0097和0.0591,时间分别缩短0.0459s和0.0612s。表明本研究提出的LightGBM模型性能更有效地提高了温室番茄冠层CWSI的预测精度,为实现温室番茄按需灌溉提供了参考。  相似文献   

3.
为快速获取大豆冠层叶片氮素含量(Leaf Nitrogen Content, LNC)信息,采用无人机获取大豆冠层LNC多光谱影像光谱特征,通过分析光谱变量与LNC的相关性,选出对大豆冠层LNC敏感的光谱变量。利用逐步回归分析方法建立黑河43、龙垦310、龙垦3401在3个关键生育时期(R1、R3、R5)大豆LNC估测模型。研究结果表明:(1)在3个品种的3个生育期,除R5时期龙垦3401品种外,NDVI与LNC具有高度相关性,说明NDVI可以较好地进行大豆冠层LNC的反演。(2)在建模的过程中发现,在R1时期龙垦3401、黑河43、龙垦310所建模型的R2和RMSE依次为0.857、0.133,0.845、0.156,0.821、0.187;在R3时期龙垦3401、黑河43、龙垦310所建模型的R2和RMSE依次为0.835、0.204,0.881、0.113,0.849、0.162;在R5时期龙垦3401、黑河43、龙垦310所建模型的R2和RMSE依次为0.835、0.208,0.814、0.215,0.836、0...  相似文献   

4.
基于椭球函数的棉花叶倾角分布动态模   总被引:4,自引:0,他引:4  
根据试验资料,在系统分析棉花冠层叶倾角时空分布规律的基础上,将整个生育期分为4个生长阶段,并利用高斯五点距离法将冠层分为5层,用椭球分布函数模拟不同生育阶段、不同高度层上的叶倾角分布密度.模型能较全面地反映整个生育期冠层不同高度上的叶倾角分布情况,且方便用于分层的光合作用模型.利用不同播期的试验资料对模型进行验证,叶倾角频率分布的模拟结果与1:1直线之间的决定系数R2和均方根误差(RMSE)分别为0.945和6.3%,表明模型具有较好的预测性和实用性.  相似文献   

5.
湿帘风机降温系统安装高度对降温效果的影响   总被引:10,自引:0,他引:10  
针对夏季温室内气温的垂直梯度大于10℃的问题,进行了湿帘风机安装高度对降温效果影响的对比试验。试验结果表明:对于冠层高度不超过2m的低矮作物,普通安装高度(湿帘高0.9m、风机高0.5m左右)时,中、下层温度分别在30℃和28℃左右,可以满足作物生长发育的温度要求;但对于番茄等植株高大的作物,其冠层常达到温室上层的高温区(34~35℃),适当提高安装位置(湿帘高2m、风机高1m左右),使得风机的流速场高于植株冠层顶部0.5m左右,使作物冠层的空气温度只有29~31℃,气温的垂直梯度只有4℃左右。  相似文献   

6.
基于圆柱面模型的仿形喷雾植物冠层密度超声量化测试   总被引:2,自引:0,他引:2  
基于低成本超声波传感器搭建了一套植物冠层超声回波信号检测系统,建立了基于圆柱面叶片分布模型的量化测试台。在正交中心复合设计试验基础上,建立了超声回波信号均值与冠层密度、探测距离的定量关系,即植物冠层密度量化模型。对已建立的植物冠层密度量化模型进行方差分析,结果表明,植物冠层密度量化模型具有显著性,且失拟性不显著。植物冠层密度量化模型决定系数R2和预测模型决定系数R2分别为0. 988 5和0. 911 4,表明试验值和预测值具有良好的一致性。为了验证已建立的植物冠层量化模型的可靠性,于室内测试台进行了4种植物在3种不同测试距离下的冠层密度验证测试,试验结果表明,实测值与模型测量值的相对误差最小为1. 230%,最大为13. 650%,平均相对误差为6. 120%,植物冠层密度量化模型对室内测试台的冠层密度测量有较好适用性。室外选择3棵不同的桂树,每棵树选择9个测试点进行验证测试,试验结果表明,实测密度与模型测量密度的最小相对误差为3. 959%,最大相对误差为20. 600%; 3棵桂树的实测密度与模型测量密度的平均相对误差分别为11. 244%、12. 246%和9. 628%,植物冠层密度量化模型对户外桂树密度测量有较好的适用性。  相似文献   

7.
为解析宁夏滴灌玉米冠层图像参数与果穗形态参数间的内在联系,提出了一种采用作物冠层图像特征参数拟合玉米果穗生长发育动态的数学方法,建立玉米灌浆期果穗发育动态估算模型,实现了基于作物冠层数字图像处理技术的玉米果穗形态无损监测。用手机相机获取不同氮素处理下滴灌玉米灌浆期的冠层图像,提取玉米灌浆期冠层图像特征参数,测定玉米穗长、穗粗和穗体积等形态参数;运用R语言进行相关性分析,其中归一化冠层覆盖系数(Cc)与玉米果穗形态参数相关性高,运用Origin软件建立Cc与果穗形态参数间的估测模型,通过R2、RMSE和nRMSE评价估测模型的精度。结果表明,Cc与玉米穗长、穗粗、穗体积等形态参数均满足指数函数关系,其中Cc与穗长的预测精度最高,决定系数R2达到0. 714,与穗粗的预测精度次之,R2为0. 601,与穗体积的R2为0. 575。由模型检验与评价结果可知,Cc与玉米果穗形态各参数间精度较高,其中R2均不小于0. 523,穗体积RMSE的值均不大于68. 986 cm3,nRMSE均不大于33. 621%。这表明基于冠层图像归一化覆盖系数的玉米果穗生长发育动态的估算具有一定的实用性,可为果穗形态参数估算和大面积玉米无损监测提供参考。  相似文献   

8.
【目的】快速准确获取大面积果园冠层叶片全氮含量(LNC ,Leaf Nitrogen Content)是实现现代精准农业的基本要求。【方法】本试验通过无人机高光谱成像仪(391.9nm ~ 1006.2nm)采集了甘肃省静宁县两个典型果园的果树冠层光谱图像,包括人工灌溉的苹果示范园与自然降雨的苹果园,综合比较两区共160份冠层叶片样本的原始光谱反射率(OD)、倒数光谱(RT)、对数光谱(LF)、一阶微分光谱(FD),构建任意两个光谱波段集组合的差值植被指数(Difference spectral index,DSI )、土壤调节植被指数(Soil Adjusted Vegetation Index ,SAVI)、归一化光谱指数(Normalized Different Spectral Index, NDSI),分析三种光谱指数与叶片氮含量的相关性,利用一元线性回归模型与光谱指数构建两区最佳苹果冠层LNC估测模型。【结果】研究表明:人工灌溉区的FD-SAVI(825,536)、自然降雨区的LF-SAVI(854,392)与LNC的相关性最强,并基于FD-SAVI、LF-SAVI构建一元线性回归模型。人工灌溉区构建的FD-SAVI-ULRM估测模型精度最高,验证集R2和RMSE为0.6601和0.0678;自然降雨区构建的LF-SAVI-ULRM估测模型精度最高,验证集R2和RMSE为0.6746和0.0665。本试验采用LNC模型绘制出两个试验区的苹果树冠层叶片LNC估测图,实现对果园叶片全氮含量的精准掌握及精细化管理。  相似文献   

9.
基于物联网的日光温室冠层特征温度时空变化规律分析   总被引:1,自引:0,他引:1  
针对日光温室冬季反季节生产中冠层温度时空分布不均的问题,以典型西北日光温室为研究对象,建立了40通道PT100温度场监测系统,对冬季番茄冠层全天候动态温度数据进行采集,在此基础上,采用克里金插值算法进行冠层温度场建模,通过差分进化算法获取温度极值点,分析了不同天气条件下冠层特征温度的时空变化规律。结果表明,晴天、多云天、阴(雨)天插值验证的R2均大于0.94,平均均方根误差分别为1.34、0.95、0.40℃,该算法更适用于阴(雨)天及夜间低温冠层温度场的插值;在不同天气条件下,温室冠层温度全天整体上呈现西高东低、内高外低的趋势,阴(雨)天温室内温度整体变化规律趋于一致,晴天、多云天气揭被后,受外界光辐射等因素影响室内温度分布差异性较大,晴天夜间温度的下降程度大于阴(雨)天;冠层极值点分布结果表明,在不同天气条件下,极值特征点在日光温室中分布区域基本相同,冠层最高温点主要位于温室中部[22.0m,2.5m]附近,最低温点主要位于温室东部外膜[4.0m,5.48m]附近。日光温室冠层极值特征点的获取为温室栽培、温度灾害监测与传感器部署等研究提供了理论基础。  相似文献   

10.
果园靶标冠层叶面积有效探测是施药量在线计算的基本依据。针对树形靶标稠密和稀疏2种冠层类型,搭建叶面积测量三维立体试验平台和激光雷达(Light detection and ranging,LiDAR)探测移动试验平台,构建不同厚度和稠密度树形靶标,采用偏最小二乘回归(Partial least squares regression,PLSR)算法与BP(Back propagation)神经网络算法建立了冠层叶面积探测模型。试验结果表明:PLSR算法获得稠密厚冠层、稀疏厚冠层、稠密薄冠层和稀疏薄冠层叶面积探测模型的决定系数(R2)分别为:0.9626、0.4130、0.8896、0.2699;BP神经网络算法获得模型的R2依次为:0.9727、0.5302、0.8993、0.4290。基于LiDAR的冠层叶面积探测模型对稠密冠层探测精度较高,R2不低于0.8896,对稀疏冠层探测精度较低,不高于0.5302,该探测方法可用于稠密冠层叶面积在线计算,指导果园精准变量喷药。  相似文献   

11.
Overland water and salt flows in a set of rice paddies   总被引:1,自引:0,他引:1  
Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m−1) and an infiltration rate of 5.8 mm day−1. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day−1), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day−1 was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.  相似文献   

12.
瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。  相似文献   

13.
对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明:该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。  相似文献   

14.
对《种子法》存在问题的探讨   总被引:1,自引:0,他引:1  
《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。  相似文献   

15.
About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.  相似文献   

16.
赵异 《湖南农机》2007,(3):31-32
在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。  相似文献   

17.
A European irrigation map for spatially distributed agricultural modelling   总被引:1,自引:0,他引:1  
We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.  相似文献   

18.
在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。  相似文献   

19.
农村信息化服务的现状及建设措施   总被引:2,自引:0,他引:2  
分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。  相似文献   

20.
车辆ABS控制算法的研究及探讨   总被引:1,自引:0,他引:1  
对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。  相似文献   

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