基于TM影像的冬小麦苗期长势与植株氮素遥感监测研究

叶面积指数和叶片氮素含量是决定小麦群体长势的重要生理指标,也是制定栽培管理措施的必要依据。利用遥感监测小麦返青后的叶面积指数和叶片氮素含量,便于及时采取施肥、灌溉、中耕等调控措施,达到优质、高产稳产、高效的目的。本文使用TM影像数据与实地GPS定位相结合的方法,研究了冬小麦返青后叶面积指数及植株氮素含量的变化态势。结果表明:(1)TM影像的NDVI的地域性差异较大,且随纬度呈现极明显的线型负相关变化态势;(2)将用NDVI反演的LAI与实测的LAI进行比较,二者较为一致,其均方差根(RMSE)为0.111;(3)利用NDVI监测的小麦植株氮素含量与实地观测的植株氮素含量较为相近,二者的RMSE为0.085。总之,利用TM影像的NDVI可以快速、精确地监测返青期小麦的LAI和植株氮素营养状况。同时,本研究结果也可为冬小麦返青期的苗情诊断和管理决策提供及时、准确的信息支持。

Study on Monitoring the Winter Wheat Growth and Nitrogen Based on Land-sat TM Image

Wheat LAI and leaf nitrogen content are important physiological indices for determining the growth condition and necessary basis for establishing cultivation and management measure.Remote sensing technology could be easily used to monitor and forecast growth condition,nitrogen level and yield and quality formation of crop.The dynamical change characteristics of wheat LAI and leaf nitrogen content after recovery of seedling was analyzed by TM image and GPS.The results showed that NDVI of TM image changed in negative correlation with latitude,and the monitored LAI and leaf nitrogen content deduced from NDVI were consistent with observed values,with the root mean square error(RMSE) of 0.111 and 0.085 respectively.This study provided a new method for seedling diagnosis and information capture,which could be used to make decision on crop production.