基于红光和近红外反射光谱特征参数反演草地地上生物量

Pasture aboveground biomass estimatingbased on spectral reflectance characters of red and near-infra red bands

2013年6~10月测定东非狼尾草＋白三叶混播草地冠层反射光谱和地上生物量;分析红光波段和近红外波段反射光谱特征参数与牧草鲜重及干物质之间的相关关系;构建并检验基于红光单波段和植被指数（NDVI、RVI、DVI）反演草地地上生物量回归模型。结果表明：红光波段反射率与草地地上生物量之间存在显著相关性;地上生物量的增加能够显著降低＂红谷＂反射率,显著升高近红外850.0nm处反射率;选用红光单波段反射率、红光波段构建的植被指数RVI或红光与近红外波段构建的植被指数NDVI,均能够精确反演草地鲜草产量和干物质产量;适宜估产的植被指数因季节和草地生物量的差异而不同,在6月11日,植被指数RVI反演模型估测的草地生物量与实测值的模拟效果最好,10月12日,植被指数NDVI反演模型估测的草地生物量与实测值的模拟效果最好。

From June to October 2013,the mixed pasture（Pennisetum clandestinum and Trifolium repens）was selected to estimate the aboveground biomass through building the estimating model by measuring the canopy spectral reflectance of the pasture and analyzing the relationship between biomass and reflectance of special wavelengths,red edge parameter and vegetation indices.Results showed that there were significant relationships between spectral reflectance in red band and pasture aboveground biomass.Reflectance at red valley could be significantly decreased and reflectance at 850.0nm could be significantly increased by increased biomass from June 11 to October 12.Reflectance of red band and vegetation index RVI as well as vegetation index NDVI could be used for estimating pasture fresh forage and dry matter yield,but the most suitable vegetative indices varied with the season and forage yield.RVI was better used in June and NDVI was better in October.