基于无人机数码影像的棉叶螨严重度监测

棉叶螨是影响棉花产量和品质的主要虫害之一。为快速、准确、有效地监测棉叶螨发生情况，利用无人机搭载数码相机获取数码影像，并计算多种可见光植被指数作为初选特征因子，然后采用ReliefF-Pearson特征降维方法选取最佳建模特征，分别构建偏最小二乘回归(PLSR)、BP神经网络(BPNN)、随机森林(RF)的棉花冠层叶片叶绿素相对含量(SPAD)值遥感估测模型和棉叶螨严重度遥感估测模型。结果表明，棉叶螨严重度与棉花冠层叶片SPAD值呈显著负相关关系。经过精度评价，确定RF模型具有最佳性能，模型验证的决定系数和均方根误差为0.74、2.13。该研究结果表明利用棉花冠层叶片SPAD值遥感估测模型可准确估测棉叶螨为害情况，为棉叶螨的无损监测和病虫害防治提供参考依据。     

基于信息熵特征选择的小麦冠层叶绿素含量估测方法

为运用图像颜色特征估测作物的叶绿素含量,以自然环境下的小麦冠层图像为研究对象,提出一种基于熵权法的颜色特征选择方法,并应用机器学习方法建立小麦冠层叶绿素含量估测模型。熵权法通过信息熵来衡量颜色特征指标权重,实现冠层图像特征排序,机器学习方法选用多元线性回归（Multiple linear regression, MLR）、岭回归（Ridge regression, RR）和支持向量回归模型（Support vector regression, SVR）估测小麦冠层叶绿素含量。试验结果表明,与皮尔逊相关系数法和主成分分析法选取的特征集进行对比,熵权法得到a*、R-G-B、R-G、（a*+b*）/L、a*/b*、(R-G)/(R+G+B)、(R-B)/(R+B)、H/S、(R-G)/(R+G)等9个特征组成的特征集,可以利用较少的特征指标达到最优的预测效果。在选取相同特征指标参数的情况下,SVR的预测能力优于其它模型,其R2和RMSE的平均值分别为0.80、1.89,相比于MLR和RR模型R2分别提升2.8%、1.1%,RMSE分别下降0.13和0.05。将基于熵权法建立的SVR模型应用到2021年采集的小麦冠层图像数据,结果表明模型具有很好的稳定性。     

基于无人机图像的玉米冠层叶绿素含量检测与分布研究

为了快速、无损地获取大田作物叶绿素含量空间分布,基于无人机遥感技术研究了大田玉米冠层叶绿素含量检测及分布图绘制方法。利用无人机遥感技术采集了150幅大田玉米的航拍图像,并通过Pix4dmapper软件对其进行了拼接;在实验田中,等距获取80株玉米叶片样本,通过化学法萃取叶绿素,并使用分光光度计测量叶绿素含量,形成了基础数据源。在数据处理方面,采用Arc GIS软件对样本点的POS(Position and orientation system)数据与无人机图像进行匹配;对无人机拍摄的RGB图像,首先进行R、G、B三通道分量值提取,构建了绿红比值、绿红差值、归一化红绿差值、超绿等10种颜色特征,并计算了均值、标准偏差、平滑度、三阶矩等6种纹理特征,然后建立了基于BP(Back propagation)神经网络的玉米冠层叶绿素含量检测模型。实验结果表明,基于BP神经网络的玉米冠层叶绿素含量检测模型的均方根误差RMSE为4. 465 9 mg/L,决定系数R~2为0. 724 6。通过BP神经网络检测模型计算出大田玉米图像每个像素点的叶绿素含量,基于伪彩色技术绘制大田玉米叶绿素含量可视化分布图,分析田间玉米冠层叶绿素含量分布图可以直观区分田间道路与冠层区域,显示地块叶绿素分布差异。通过无损检测大田玉米冠层叶绿素含量及叶绿素分布可视化,可为田间作物长势评价和精细化管理提供技术支持。     

基于高光谱的甜菜SPAD值估算研究

叶绿素作为植物体内参与光合作用的重要色素,其含量对作物生长状况、产量和品质有很大影响。为此,利用野外便携式ASD光谱仪,实测了田间甜菜冠层光谱数据,且用SPAD-502叶绿素仪测定叶片SPAD值。基于原始光谱和一阶导数光谱与SPAD值相关性,选取植被指数和波段深度信息建立SPAD值预测模型,并用对照田试验数据对模型进行验证。通过对比植被指数建立的回归模型及波段深度分析,结合多元逐步回归建立的估算模型可知,波段深度比(BDR)结合SMLR建立的估算模型验证结果最好(RMSE=2.54,RE=4.5%)。研究结果表明:导数处理能提高光谱数据与SPAD值相关系数,波段深度信息结合多元逐步回归相比植被指数能提高SPAD值估算精度。     

田间冬小麦抽穗期长势分析——基于可见-近红外光

为了快速估测大田冬小麦叶绿素含量指标,指导冬小麦抽穗期追肥管理,基于光谱分析技术在可见光和近红外波段(325~1 075 nm)处,对陕西省杨凌区揉谷镇粮食基地的冬小麦进行长势检测、分析。试验在1 000 m×600 m区域内划分为30个采样区进行数据采集,使用ASD Field Spec Hand Held光谱辐射仪(Analytical Spectral Devices.,USA)采集冬小麦的冠层光谱反射率数据,使用SPAD-5 0 2 Plus便携式叶绿素仪测量小麦倒一叶和倒二叶的叶绿素指标(SPAD值),使用G738 CM型手持式GPS记录采样点的位置信息。分别进行冠层光谱反射率小麦倒一叶和倒二叶的预处理,结果表明:冠层反射光谱倒二叶的SPAD值相关系数高于倒一叶。基于相关性分析,选取4个敏感波段538、661、740、850 nm分别与预处理前后的光谱数据进行多元线性回归分析,结果表明:预处理后的模型精度较高,建模精度R2=0.8 3,验证建模精度R2=0.7。同时,绘制了大田作物长势分布图,可为冬小麦抽穗期追肥提供支持。     

基于高光谱成像的马铃薯叶片叶绿素分布可视化研究

针对马铃薯作物叶片进行了叶绿素含量无损检测技术及分布图绘制方法研究,用以指示作物长势并指导精细化管理。首先利用高光谱成像技术采集了65个马铃薯叶片的400个样本点高光谱图像和相应的SPAD值,提取并计算叶绿素测量区域的叶片平均光谱后,分别采用蒙特卡罗无信息变量消除算法（MC-UVE）和自适应重加权算法（CARS）筛选出了12个和23个叶绿素含量敏感波长,建立了马铃薯叶片叶绿素含量偏最小二乘（PLS）回归模型。建模结果如下：基于MC-UVE算法筛选的12个敏感波长的PLSR诊断模型,建模精度R2C为0.79,验证精度R2V为0.73;基于CARS算法筛选的23个敏感波长建立的PLSR诊断模型,建模精度R2C为0.82,验证精度R2V为0.80。择优选取CARS-PLSR模型计算马铃薯叶片每个像素点的叶绿素含量,从而利用伪彩色绘图绘制了马铃薯叶片叶绿素含量可视化分布图,最终实现马铃薯叶片含量无损检测以及叶绿素分布可视化表达,以期为后续马铃薯作物大田冠层叶绿素分布诊断提供支持。     

基于L-系统的3D虚拟植物冠层光合作用模拟模型

为定量分析植物冠层结构与光分布及光合作用之间的关系,模拟实际环境中植物冠层的实时光合速率,为诸如作物模型中产量估测提供一种植物冠层尺度光合生产力计算方法,本文构建了基于L-系统的3D虚拟植物冠层光合作用模拟模型。模型主要分为3部分:基于L-迭代文法系统与三维图形绘制技术构建3D虚拟植物冠层结构,利用正向光线跟踪及天空可见率算法模拟虚拟冠层内光辐射(Photosynthetically active radiation,PAR)传输,基于太阳几何参数、大气影响参数及地理位置等参数计算真实环境中虚拟冠层顶部实时PAR强度。利用此模型,直接输入或插值处理光合环境因子数值,采用单叶光合作用模型和相关呼吸作用模型,可计算冠层内净光合作用速率并进行周期内植物体生物量的积累估算。以实测的幼龄杉木为模拟对象,计算其冠层内净光合作用速率及周期内生物量积累,模拟结果表明,基于虚拟冠层的PAR分布模拟及其冠层光合作用速率计算,是一种对植株光合生产力估算的有效方法。     

基于无人机多光谱遥感的夏玉米冠层叶绿素含量估计

为探讨利用无人机多光谱遥感影像监测夏玉米冠层叶绿素含量的可行性,基于2019年不同施氮水平下(0,105,210,315 kg·N/hm²)夏玉米多光谱遥感影像和田间实测冠层叶绿素含量数据,分析了不同施氮水平下夏玉米冠层叶绿素含量的变化规律,同时选取10种常用光谱植被指数与实测冠层叶绿素含量进行相关性分析,采用与实测叶绿素含量极显著相关的9种植被指数,构建了基于遥感光谱指数的夏玉米冠层叶绿素含量遥感监测模型,并通过精度检验确定最优估测模型.结果表明,施用氮肥能够提高夏玉米冠层叶绿素含量,过量氮肥不能持续提高叶绿素含量,同一施氮水平下不同追肥处理之间叶绿素含量没有明显差异.绿色归一化植被指数与叶绿素含量的相关性系数最高,达到了0.892.采用逐步回归分析方法建立的模型表现最优,决定系数为0.87,均方根误差及相对误差分别为0.15和2.68%.因此,无人机多光谱遥感结合逐步回归模型可以实现田间尺度的夏玉米冠层叶绿素含量的实时监测.     

基于PROSAIL模型偏差补偿的水稻叶绿素含量遥感估测

以东北水稻为研究对象,以提高叶绿素估测精度和模型可解释性为目标,提出了一种混合建模方法。以PROSAIL辐射传输机理模型为基础,模拟水稻冠层光谱,建立叶绿素含量的查找表,初步估测叶绿素含量,并采用最小二乘支持向量机(LSSVM)建立误差模型,对PROSAIL模型偏差进行补偿,弥补PROSAIL建模时产生的误差。为验证模型的估测能力,选取13种与作物叶绿素关系较为密切的植被指数,通过不同统计模型的模拟分析,筛选出4种较优的植被指数,分别建立单因子输入的最优预测模型(GNDVI、RSI、(S_(Dr)-S_(Db))/(S_(Dr)+S_(Db))的乘幂模型及MCARI的指数模型)。以4种植被指数作为输入,利用偏最小二乘法(PLS)、LSSVM回归法、BP神经网络及本文提出的混合建模方法分别构建水稻叶绿素含量多因子预测模型,并进行估测和验证。结果表明,相比单因子输入的最优预测模型,混合模型具有较低的预测偏差,其建模集R~2=0. 740 6,RMSE为0. 985 2 mg/dm~2,验证集R~2=0. 733 2,RMSE为1. 084 3 mg/dm~2。与采用其他多因子预测模型相比,本文方法具有较高的估测精度和良好的鲁棒性。另外,混合建模方法以PROSAIL模型为基础,物理意义较为明确,提高了预测模型的可解释性。本文可为作物叶绿素含量估测提供新的思路和方法,为诊断水稻氮营养含量和监测水稻长势提供参考。     

基于相对叶绿素含量的黄瓜叶色仿真

提出了一种基于相对叶绿素含量的植物叶片颜色仿真方法,通过连续对正常生长状态下的黄瓜叶片图像采集及相对叶绿素含量SPAD值测定,建立了黄瓜叶片颜色分量与SPAD值的数学关系模型,并采用均方根误差(RMSE)对模型进行验证,结果显示叶片的3个颜色分量R、G、B的实测值与模拟值之间的RMSE为13.43%、8.47%、7.42%,模拟效果较好。通过结合叶片色素浓度分布图对叶色空间分布进行仿真,并采用高级着色器语言实现了黄瓜叶片表观颜色变化过程的可视化模拟,获得了较好的真实感效果。     

Overland water and salt flows in a set of rice paddies

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.     

瓦房店市水果生产标准化发展研究

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。     

金谷子耐旱TG118引种试种及推广应用

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。     

对《种子法》存在问题的探讨

《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。     

Review of the Egyptian experience in implementing land drainage projects

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.     

和谐社会理论建设的几点哲学思考

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。     

A European irrigation map for spatially distributed agricultural modelling

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.     

粉质仪和拉伸仪在面粉生产中的应用

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。     

农村信息化服务的现状及建设措施

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。     

车辆ABS控制算法的研究及探讨

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。