高光谱遥感在农作物长势监测中的应用

该研究是加拿大Saskatchewan Scott农作物轮作系统(ACS)研究的一部分。研究始于1994年,历时18a,评价9个可耕种农作物产量系统的可靠性。由3种处理水平(organic,reduced,high)和3种作物多样性水平(low,diversified annual grains,diversified annual perennials)结合而产生的9个农作物产量系统,被用于监测和评价加拿大牧场不同处理和不同作物种植轮作下可耕种农作物的产量。在2003年生长季共收集了3次叶面积指数和光谱反射率的数据:生长季前期(6月)、生长季旺盛期(7月)、生长季后期(8月)。叶面积指数是由LAI-2000植物冠层分析仪监测的,光谱测量是由覆盖了350-2500 nm波长范围共2215个波段的ADS便携式高光谱仪完成的。结果显示,光学测量可以用于监测农作物生长状况的差异。从生长季的早期到中期,光谱和叶面积指数在不同处理下有显著差异。7月中期是用遥感资料监测农作物长势的最佳季节;红光波段与近红外波段反射率的比值和基于这两个波段构造的归一化植被指数,是检测农作物长势的最佳植被指数。

Monitoring Growth Vigour of Crop Using Hyperspectral Remote Sensing Data

This study was conducted as part of the Alternative Cropping Systems(ACS) study at Scott,Saskatchewan.The 18 year study was initiated in 1994 to evaluate the sustainability of nine arable crop production systems.The nine cropping systems,derived from combinations of three input levels(organic,reduced,and high) and three cropping diversity levels(low,diversified annual grains,and diversified annual perennials),were designed to monitor and assess alternative input use and cropping strategies for arable crop production on the Canadian Prairies.Optical field data including leaf area index and spectral reflectance were collected three times along the growing season of 2003: early growing season(June),maximum growing season(July) and late growing season(August).Leaf area index(LAI) was measured with an LAI-2000 plant canopy analyzer.The spectral measurements were made with a handheld ADS spectroradiometer,which covers wavelengths from 350 nm to 2500 nm with 2215 bands.Results showed that optical measurements can be used to indicate different crop conditions.The spectral and LAI differences among input levels were significant at early to mid growing seasons.Mid July is the best season and the red over near infrared spectral ratio as well as the normalized difference vegetation index based on these two bands are the best vegetation indices to use remotely sensed data for crop vigor monitoring.