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1.
一个作物发育动态理论模型 总被引：1，自引：0，他引：1
在分析作物发育特性及作物发育与环境及措施因子关系的基础上，建立了一个作物发育动态的理论模型（ＣＰＴＭ），该模型为乘积形式的旨数模型。模型具有较好的解释能力，并适于生育进程的计算机模拟。应用于小麦的发育动态建模，模拟值与实测值非常接近，模拟性能良好。通过确定可控因子函数ｆＥＣ、影响效应值ＥＥｉ和参数ｋ与ｅｉ，作物发育的理论模型原则上适应于所有作物。 相似文献
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现代温室黄瓜发育动态模型研究 总被引：4，自引：0，他引：4
为了研究现代温室黄瓜发育动态模型,动态掌握作物的生长规律。通过对黄瓜生长的连续定期试验观测,将黄瓜生育期划分为7个阶段,采用生长度日法建立温室黄瓜发育进程模拟模型,同时对模型进行了检验,并确定了各生育阶段的生长度日参数。用逐日平均温度替代了各生育阶段的日平均温度,所建立的发育模拟模型能连续动态地模拟作物生长到任一阶段时的发育进程,从而有效地预测出黄瓜各生育阶段经历的天数。通过模拟值与观测值的比较表明所建立的黄瓜发育模型模拟精度较高,预测效果较好。该模型对作物生长发育具有较好的预测性和可行性,为进一步有效建立作物生长动态模型奠定了基础。 相似文献
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根据作物生理、作物生态、农业气象等学科的基本原理,建立了逐时水稻冠层光合生产动态模拟模型,模型包含辐射、气温２个气象因子和密度、Ｎ肥、播种期３个栽培因子．模拟模型由５个子模型耦合而成,即发育子模型,光合生产和干物质积累子模型,固化物分配和叶面积动态子模型,产量形成子模型和辐射、气温模拟子模型．利用模型对水稻生长的动态过程进行仿真,将模拟值和实测值进行比较,两者拟合程度较好 相似文献
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水稻计算机模拟及应用：Ⅰ.水稻生长及产量形成模拟模型构建 总被引：4，自引：0，他引：4
根据作物生理、作物生态、农业气象等学科的基本原理,建立了逐时水稻冠层光合生产动态模拟模型,模型包含辐射,气温２个气象因子和密度、Ｎ肥、播种期３个栽培因子。模拟模型由５个子模型耦合而成,即发育子模型,光合生产和干物质积累子模型,固化物分配和叶面积动态子模型,产量形成子模型和辐射,气温模拟子模型。利用模型对水稻生长的动态过程进行仿真,将模拟值和实测值进行比较,两者拟合程度较好。 相似文献
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《中国农业科技导报》2010,(3):83-83
从稻麦生产管理的信息化角度出发,运用定量遥感技术、作物模拟技术和GIS技术,依据遥感信息一作物模型一长势和产量一气候环境的系统动态关系,以定量遥感反演及其与作物模型的耦合为主线,分析遥感光谱特征、农学参数与生态环境因素间的动态关系,明确影响稻麦光谱特征的主要气候环境因子,建立基于主要气候因子的农学参数遥感反演模型; 相似文献
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作物生长发育过程的计算机模拟决策研究概述 总被引：11，自引：0，他引：11
种植业是农业的基础产业 ,作物生长发育过程的计算机模拟决策研究是种植智能化、数字化与精确化的桥梁与纽带。本文对作物计算机模型的定义、模型分类、产生和发展、应用及意义等进行了概述。作物模拟技术经历了初创、发展及完善与成熟阶段。作物模拟研究的作用主要有解释作物生长过程的机理、预测及调控指导 3个方面 ,其目的主要有定量关系、综合知识、检验假设、进行模拟、支持决策与教学及连接其它模型等 ,其意义主要表现在为人们提供了新的认知工具 ,使作物生产决策向动态、定量、目标与优化方向发展 ,实现智能化与精确化管理 ,推动农业信息化与可持续发展 相似文献
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《农业科学学报》2017,(2)
Variation in phenological stage is the major nonlinearity in monitoring,modeling and various estimations of agricultural systems. Indices are used as a common means of evaluating agricultural monitoring data from remote sensing and terrestrial observation systems,and many of these indices have linear characteristics. The analysis of and relationships between indices are dependent on the type of plant,but they are also highly variable with respect to its phenological stage. For this reason,variations in the phenological stage affect the performance of spatiotemporal crop status monitoring. We hereby propose an adaptive event-triggered model for monitoring crop status based on remote sensing data and terrestrial observations. In the proposed model,the estimation of phenological stage is a part of predicting crop status,and spatially distributed remote sensing parameters and temporal terrestrial monitoring data are used together as inputs in a state space system model. The temporal data are segmented with respect to the phenological stage-oriented timing of the spatial data,so instead of a generalized discrete state space model,we used logical states combined with analog inputs and adaptive trigger functions,as in the case of a Mealy machine model. This provides the necessary nonlinearity for the state transitions. The results showed that observation parameters have considerably greater significance in crop status monitoring with respect to conventional agricultural data fusion techniques. 相似文献
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作物物候期识别是农情遥感监测的重要内容,及时准确识别作物物候期,对有效评估作物生长趋势、提高农情信息化管理水平有重要意义。提出了基于时间序列全极化合成孔径雷达(polarimetric synthetic aperture radar, PolSAR)数据结合决策树模型的油菜物候期识别方法。首先,采用3种极化分解方法提取PolSAR极化参数,并分析各极化参数对油菜物候期的动态响应规律;其次,基于各极化分解方法提取的参数建立决策树模型,并对油菜物候期进行分类识别;最后,采用基于混淆矩阵的方法对油菜物候期识别结果进行精度评价。采用5期Radarsat-2 PolSAR数据和地面物候观测数据进行实验验证。结果表明:提取的PolSAR参数中对物候期变化较为敏感的参数有H/A/alpha分解中的散射角(Alpha)、特征值(L2、L3)、伪熵(P2)、目标方位角(Beta1)参数,Freeman-Durden分解中的地面散射(Ground)和奇次散射(Odd)参数,Yamaguchi分解中的奇次散射(Odd_Y)和螺旋体散射(Helix)参数;决策树模型对油菜物候期识别结果较为准确,识别结果中组合3种极化分解方法提取参数建立的原始决策树模型分类总体精度最高,达94%。总体上,PolSAR极化分解参数对油菜物候期变化比较敏感,决策树模型能有效识别油菜物候期。 相似文献
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基于本体的作物系统模拟框架构建研究 总被引：4，自引：0，他引：4
【目的】研究作物系统模拟框架（CSSF）可以为构建作物生长模型及设计可重用的作物系统模拟软件提供基础框架。【方法】将本体技术应用于作物模拟模型领域,以作物生长的基础生理生态过程为主线,基于仿真本体和作物模拟本体,综合分析与提炼稻麦棉油等作物的建模流程、生长模拟模型算法及模型参数中的共性概念及概念之间的相互关系,构建了CSSF。【结果】CSSF包括作物建模外部知识框架（CMOKF）和作物模型内部知识框架（CMIKF）,其中CMOKF提炼了作物系统受时间、空间和自然环境共同驱动的共享特征,CMIKF描述了生育期、生物量积累、干物质分配与产量形成、器官建成、作物-土壤水分动态和养分平衡等作物模型组分与模型算法的共性特征。【结论】CSSF实现了作物建模概念、流程、结构和方法的知识级共享,对设计可重用的作物模型软件体系结构具有指导作用。 相似文献
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Gregory S. McMaster D.A. EdmundsW.W. Wilhelm D.C. NielsenP.V.V. Prasad J.C. Ascough II 《Computers and Electronics in Agriculture》2011,77(1):118-125
Crop phenology is fundamental for understanding crop growth and development, and increasingly influences many agricultural management practices. Water deficits are one environmental factor that can influence crop phenology through shortening or lengthening the developmental phase, yet the phenological responses to water deficits have rarely been quantified. The objective of this paper is to provide an overview of a decision support technology software tool, PhenologyMMS V1.2, developed to simulate the phenology of various crops for varying levels of soil water. The program is intended to be simple to use, requires minimal information for calibration, and can be incorporated into other crop simulation models. It consists of a Java interface connected to FORTRAN science modules to simulate phenological responses. The complete developmental sequence of the shoot apex correlated with phenological events, and the response to soil water availability for winter and spring wheat (Triticum aestivum L.), winter and spring barley (Hordeum vulgare L.), corn (Zea mays L.), sorghum (Sorghum bicolor L.), proso millet (Panicum milaceum L.), hay/foxtail millet [Setaria italica (L.) P. Beauv.], and sunflower (Helianthus annus L.) were created based on experimental data and the literature. Model evaluation consisted of testing algorithms using “generic” default phenology parameters for wheat (i.e., no calibration for specific cultivars was used) for a variety of field experiments to predict developmental events. Results demonstrated that the program has general applicability for predicting crop phenology and can aid in crop management. 相似文献
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水稻生育期预测的非线性发育模型 总被引：2，自引：0，他引：2
殷新佑 《江西农业大学学报》1992,14(3):224-229
在水稻模拟研究中发育期预测是基础环节。因为它为模拟作物生产力提供时间上的框架。目前对水稻发育过程尚未完全研究清楚,难以用解释性模型来描述。生产上普遍使用的积温法有一定问题,因为它隐含着发育速度与温度呈线性关系。本研究发现:对于调节IR8(籼稻)和藤坂5号(粳稻)播种到开花期间的发育速度,夜温比昼温有更大的效应。这一现象假设是由于发育速度与温度呈非线性关系引起的,因为夜温通常比昼温低。基于这一假设,本研究提出一个解释性能较好的非线性模型来量化水稻发育对温度的反应,并用相乘法则来综合温度和光周期的效应。该模型比线性加性模型和CERES-Rice中的发育模型有更好的预测性能,尽管由于数据观察值本身的异质性,模拟值与观察值还有一定差异。这种异质性来源之一是移栽效应,它在基因型(品种)间的差异似乎较小。为改善模型的预测性能,移栽效应可以作为一个乘子引入模型中以修饰光温效应。 相似文献
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Longhui Li Gregory S. McMaster Qiang Yu Jun Du 《Computers and Electronics in Agriculture》2008,63(2):274-281
Predicting crop developmental events is fundamental to simulation models and crop management decisions. Many approaches to predict developmental events have been developed, however, most only simulate the mean time for reaching a developmental event. An exponential sine equation developed by Malo [Malo, J.E., 2002. Modelling unimodal flowering phenology with exponential sine equation. Funct. Ecol. 16, 413–418] to predict flower number over time was modified to incorporate the response of crop development rate to temperature. The revised model (ExpSine model) uses the base, optimum, and maximum cardinal temperatures specific to a crop or genotype. Most model parameters were estimated from the literature, and four of the five model parameters have physiological significance. Model evaluation for winter wheat (Triticum aestivum L.) was based on two controlled environment studies from the literature and two field experiments conducted in the North China Plain (NCP) and the Tibet Plateau (TPC). The r2 for the modified temperature response function was 0.74 and 0.91 for two different experiments and compared very well (identical mean r2's) to an existing function (Beta model) [Yin, X., Kropff, M.J., McLaren, G., Visperas, R.M., 1995. A nonlinear model for crop development rate as a function of temperature. Agric. Forest Meteorol. 77, 1–16]. Differences between observed and predicted flowering dates ranged from −2 to 3 days in the NCP and from −7 to 4 days on the TPC, with the mean percent error in both sites less than 1% and no apparent bias observed in the model. This modification of Malo's exponential sine equation expanded the predictive ability of the original equation to simulate phenology across a broader range of environments. The ExpSine model developed can be used as a phenological module in various crop or ecological simulation models. 相似文献
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A modified version of the widely used CERES-Wheat phenology model (CWm) was developed introducing variable thermal time from double ridge stage to flag leaf emergence and compared with the original model (CW V3.x). Both model versions were newly implemented and calibrated using routinely collected field ratings of phenological stages of winter wheat crops. Calibration for all parameters of both model versions was done using a step by step procedure thereby using different methods for parameter identification. For calibration and validation of the model a data set containing more than 6000 single observations of wheat phenology was used. The improved model version had a better prediction of phenological (BBCH) stages compared to the original CW approach for an independent validation data set. The average RMSE for BBCH 37 and BBCH 39 was decreased by two and five days, respectively. We could show that it was possible to calibrate the wheat phenology models using solely routinely available field ratings. Because the predictive quality for wheat phenology of actual wheat crop growth simulators without calibration especially often is still limited the presented approach may be seen as an approach for improving this type of models without especially designed experiments. 相似文献
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Characterizing Spatial Patterns of Phenology in Cropland of China Based on Remotely Sensed Data 总被引：3，自引：0，他引：3
WU Wen-bin YANG Peng TANG Hua-jun ZHOU Qing-bo CHEN Zhong-xin Ryosuke Shibasaki 《中国农业科学(英文版)》2010,9(1):101-112
This study used time-series of global inventory modeling and mapping studies （GIMMS） normalized difference vegetation index （NDVI） datasets at a spatial resolution of 8 km and 15-d interval to investigate the spatial patterns of cropland phenology in China. A smoothing algorithm based on an asymmetric Gaussian function was first performed on NDVI dataset to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination. Subsequent processing for identifying cropping systems and extracting phenological parameters, the starting date of growing season （SGS） and the ending date of growing season （EGS） was based on the smoothed NVDI time-series data. The results showed that the cropping systems in China became complex as moving from north to south of China. Under these cropping systems, the SGS and EGS for the first growing season varied largely over space, and those regions with multiple cropping systems generally presented a significant advanced SGS and EGS than the regions with single cropping patterns. On the contrary, the phenological events of the second growing season including both the SGS and EGS showed little difference between regions. The spatial patterns of cropping systems and phenology in Chinese cropland were highly related to the geophysical environmental factors. Several anthropogenic factors, such as crop variety, cultivation levels, irrigation, and fertilizers, could profoundly influence crop phenological status. How to discriminate the impacts of biophysical forces and anthropogenic drivers on phenological events of cultivation remains a great challenge for further studies. 相似文献
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Emerging strategies and technologies in agriculture, such as precision farming and phenotyping depend on detailed data on all stages of crop development. Unmanned aerial vehicles promise to deliver such time series as they allow very frequent measurements. In this study, we analyse a field trial with two barley cultivars and two contrasting sowing densities in a random plot design over 2 consecutive years using the aerial images of 28 flight campaigns, providing a very high temporal resolution. From empirically corrected RGB images, we calculated the green-red-vegetation-index (GRVI) and evaluated the time-series for its potential to track the seasonal development of the crop. The time series shows a distinct pattern during crop development that reflected the different developmental stages from germination to harvest. The simultaneous comparison to ground based assessment of phenological stages, allowed us to relate features of the airborne time series to actual events in plant growth and development. The measured GRVI values range from ?0.10 (bare soil) to 0.20 (fully developed crop) and show a clear drop at time of ear pushing and ripening. Lower sowing densities were identified by smaller GRVI values during the vegetative growth phase. Additionally, we could show that the time of corn filling was strongly fixed and happened around 62 days after seeding in both years and under both density treatments. This case study provides a proof-of-concept evaluation how RGB data can be utilized to provide quantitative data in crop management and precision agriculture. 相似文献
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Synthetic aperture radar (SAR) is an effective and important technique in monitoring crop and other agricultural targets because its quality does not depend on weather conditions. SAR is sensitive to the geometrical structures and dielectric properties of the targets and has a certain penetration ability to some agricultural targets. The capabilities of SAR for agriculture applications can be organized into three main categories: crop identification and crop planting area statistics, crop and cropland parameter extraction, and crop yield estimation. According to the above concepts, this paper systematically analyses the recent progresses, existing problems and future directions in SAR agricultural remote sensing. In recent years, with the remarkable progresses in SAR remote sensing systems, the available SAR data sources have been greatly enriched. The accuracies of the crop classification and parameter extraction by SAR data have been improved progressively. But the development of modern agriculture has put forwarded higher requirements for SAR remote sensing. For instance, the spatial resolution and revisiting cycle of the SAR sensors, the accuracy of crop classification, the whole phenological period monitoring of crop growth status, the soil moisture inversion under the condition of high vegetation coverage, the integrations of SAR remote sensing retrieval information with hydrological models and/or crop growth models, and so on, still need to be improved. In the future, the joint use of optical and SAR remote sensing data, the application of multi-band multi-dimensional SAR, the precise and high efficient modeling of electromagnetic scattering and parameter extraction of crop and farmland composite scene, the development of light and small SAR systems like those onboard unmanned aerial vehicles and their applications will be active research areas in agriculture remote sensing. This paper concludes that SAR remote sensing has great potential and will play a more significant role in the various fields of agricultural remote sensing. 相似文献