小麦冠层营养诊断光谱检测仪设计与试验

Design and Test of Nutrition Diagnosis System for Wheat Canopy Based on Spectroscopy

为了快速准确获取田间作物生长营养水平信息,设计了作物冠层营养诊断光谱检测仪,并进行了小麦大田测试。系统由光学传感器,信号采集驱动模块和控制器组成。光学传感器可测量300~1 100 nm范围内连续光谱,信号采集驱动模块用于提供稳定电压以及数据的A/D转换。开发了光谱采集控制软件安装于控制器,主要功能包括接收、处理、显示和存储采集到的数据。应用该仪器进行了标定试验,并针对大田冬小麦开展了大田试验,试验结果表明该仪器所测反射率与美国ASD Field Spec Hand Held 2光谱辐射仪所测的反射率之间具有较高的相关性,相关系数最低为0.991 8。分析了冬小麦叶绿素含量指标SPAD值与仪器所测反射率之间的相关性。选出相关性较高的550~900 nm波段进行主成分分析建立叶绿素预测模型,建模R2C为0.575,模型检验R2V为0.595。结果表明利用研发的便携式光谱检测仪能有效评估小麦营养叶绿素含量,为小麦的精细栽培提供理论与技术支持。

In order to realize precision management of wheat crop,a spectral analyzer was developed to diagnose crop canopy nutrition,and the performance experiment was conducted in a wheat field. The system consisted of optical system,signal acquisition driver module and controller. The optical sensor could collect spectral reflectance between 300 nm and 1 100 nm. The signal acquisition driver module was used to provide a stable voltage and A / D conversion. A spectral acquisition and control software was developed to receive,display,process and save the collected data. Calibration experiments and field experiments were carried out in wheat experimental field. The correlation between the result measured by the spectral analyzer and the result of ASD Field Spec Hand Held 2 were analyzed. The results indicated that high correlation existed between the reflectance datasets detected by the two equipments. The minimum coefficient of correlation was 0. 991 8. The correlation between the winter wheat chlorophyll content and reflectance measured by instrument was analyzed.Selecting the higher correlation band at 550 ~ 900 nm,the principal component analysis was applied to establish chlorophyll forecasting model. The determination coefficient R2 of the calibration model was 0. 575 and the R2 of the validation model was 0. 595. Results show that the developed instrument can effectively detect and evaluate chlorophyll content of wheat canopy,and provide theoretical and technical support for the precision cultivation of wheat.