基于CGMD302光谱仪的甜玉米生长发育指标监测研究

Growth Parameter Monitoring of Sweet Corn by CGMD302 Spectrometer

为了明确甜玉米不同生育期生长发育指标与光谱仪冠层光谱参数的定量关系,进而为甜玉米生长指标快速监测提供决策依据,开展了正甜68不同施钾水平的田间试验,于拔节期、大喇叭口期以及抽雄期利用CGMD302光谱仪采集玉米冠层光谱反射率,并同步测定各处理茎粗、叶面积指数(LAI),研究各光谱参数与生长指标之间的关系。结果表明,归一化植被指数(NDVI)与茎粗和LAI呈正相关关系,而比值植被指数(RVI)与茎粗和LAI呈负相关关系。经检验,基于NDVI和RVI构建的单个时期监测模型可以有效地反演甜玉米茎粗和LAI,模型检验结果良好,预测精度均在0.9以上,均方根误差均小于10%,平均相对误差均小于5%。

In order to clarify the quantitative relationship between the growth parameters and ca- nopy spectral index of sweet corn and provide the decision basis for rapidly monitoring the growth indicators of sweet corn, the field experiment of Zhengtian 68 was carried out, with different levels of K application. The spectral reflectance of corn canopy was measured by CGMD302 spectrome- ter at different growth stages,while the stem diameter and leaf area index（LAI） were measured at the same time, and then the relations between canopy spectral index and growth parameters were analyzed. The results showed that NDVI had positive correlation with stem diameter and LAI,while RVI had negative correlation with stem diameter and LAI. The monitoring model for a single stage was constructed based on NDVI and RVI,which could well reflect the stem diame- ter and LAI of sweet corn and give the good test result. The prediction accuracy was above 0.9, the error of mean square root was less than 10% ,and the average relative error was less than 5%.