基于光谱植被指数的烤烟氮碱量及氮碱比监测研究

[目的]为了实现烤烟氮碱量及氮碱比田间动态变化的实时无损监测,设计了基于MSR216型多光谱辐射计的烤烟氮碱量及氮碱比监测试验。[方法]设置2种施氮模式,以基于SPAD(叶绿素仪)值精准氮素施肥管理(阈值为43)进行建模,利用当地生产上农家常规施氮模式进行验证。用多光谱辐射计采集烤烟的冠层光谱数据,并对烤烟6个生长时期的氮碱量、氮碱比与可见光波段及近红外波段反射率组成的比值植被指数、归一化植被指数、差值植被指数进行相关性分析。[结果]叶片烟碱含量与归一化植被指数NDVI(870,510)的相关系数最高(r=0.900);全氮含量和氮碱比则与比值植被指数RVI(1 650,710)的相关系数最高(r=0.898、0.911)。氮碱量、氮碱比与植被指数均构建了最佳的监测模型,模型预测精度分别达到0.935、0.827、0.926,RMSE分别为0.574、0.553、1.245,预测效果较好。[结论]冠层光谱能够较好地监测和跟踪冠层氮碱量以及氮碱比的动态变化。

Monitoring Total Nitrogen, Nicotine and Nitrogen-Nicotine Ratio with Spectrum Vegetation Index in Flue-Cured Tobacco

[ Objective ] In order to provide technical support for the diagnosis of the non-destructive, real-time growth and intelligent control-ling in the the production of high-quality tobacco, mornitoring trial was carried out to monitor dynamic changes of total nitrogen, nicotine and nitrogen-nicotine ratio non-invasively in real-time by MSR216 multi spectral radiometer. [ Method] Two nitrogen application patterns had been set, modeled by SPAD value-based real-time nitrogen management （RTNM） mode （ threshold was 43 ） and verified by nitrogen application pattern from local production. The relationships between the spectrum vegetation index and total nitrogen, nicotine and nitrogen-nicotine ratio at six different growth stages on the management of SPAD value-based real-time nitrogen were investigated. [ Result] The correlation coefficient of normalized difference vegetation index NDVI （870, 510 ） to nicotine was the highest （r = 0. 900 ） and the correlation coefficient of ratio vegetation index RVI （ 1 650,710） to nitrogen, nitrogen-nicotine were the highest（r =0. 898, r =0. 911 ）. By modeling and verifying, the co-efficients of determination respectively reached 0. 935, 0. 827, 0. 926 and RMSE were 0. 574, 0. 553, 0. 870 respectively. The predictive re-suits were reasonable. [ Conclusion ] The model could be used to monilor and predict the dynamic changes of total nitrogen, nicotine and nitro-gen-nicotine ratio.