不同生育期核桃树冠层叶绿素含量高光谱估算研究  

Study on hyperspectral estimation of chlorophyll content in walnut tree canopy at different growth periods

作　　者：王鑫梅 张劲松[1,2] 孟平[1,2] 汪贵斌[2] 孙圣[1] WANG Xinmei;ZHANG Jinsong;MENG Ping;WANG Guibin;SUN Sheng(Research Institute of Forestry,Chinese Academy of Forestry,Beijing 100091,China;Coinnovation Center for Sustainable Forestry in Southern China,Nanjing Forestry University,Nanjing 210037,China)

机构地区：[1]中国林业科学研究院林业研究所,北京100091 [2]南京林业大学南方现代林业协同创新中心,江苏南京210037

出　　处：《河北农业大学学报》2021年第2期63-71,共9页Journal of Hebei Agricultural University

基　　金：中央级公益性科研院所基本科研业务费专项基金(CAFZC2017M005、CAFYBB2017ZX002);国家科技支撑计划课题(2015BAD07B05)。

摘　　要：无损、实时、精准地对核桃树冠层叶绿素含量进行高光谱估算,对核桃树生长监测、营养诊断具有重要的指导意义。本研究以连续2年测定126棵核桃树不同生育期冠层光谱反射率及叶绿素含量,分析果实膨大期、果实硬核期、油脂转化期和果实成熟期4个生育期冠层光谱变化规律及叶绿素含量变化特征;在冠层光谱反射率400~1 000 nm范围内计算任意两波段组合生成的RVI、DVI和NDVI指数与各生育期冠层叶绿素含量的相关性,确定各生育期最佳敏感波段组合;基于RVI、DVI和NDVI指数构建不同生育期冠层叶绿素含量估算模型,并用第2年监测数据对估算模型进行精度验证。结果表明:(1)核桃树冠层叶绿素含量随着生育期的推进,呈现先增加后降低的趋势,各生育期叶绿素含量的变异系数和标准偏差存在明显差异,冠层叶绿素含量在油脂转化期最大,果实膨大期最小;(2)从果实膨大期到果实成熟期,在可见光波段冠层光谱反射率与冠层叶绿素含量呈负相关关系,在760~1 000 nm的近红外波段由负相关变为正相关;(3)基于两波段组合生成的RVI、DVI和NDVI指数均在油脂转化期与叶绿素含量相关性最大,估算模型拟合效果更好,且精度更高。其中,RVI指数构建的模型在核桃树中后期估算精度较高,前期较低;DVI指数构建的模型在核桃早中期估算精度较高,后期较低;而基于NDVI指数构建的估算模型,在各生育期对叶绿素含量的估算效果均最为理想,验证精度最高。因此,基于两波段组合生成的NDVI指数构建的估算模型,适用于核桃树整个生育期冠层叶绿素含量的估算研究。Non-destructive, real-time and accurate estimation of Juglans regia canopy chlorophyll values using hyperspectral remote sensing has a strong guiding significance for Juglans regia tree growth monitoring and nutritional diagnosis. This study determined the canopy spectral reflectance and chlorophyll values of 126 Juglans regia trees at different growth periods for 2 consecutive years. The characteristics of canopy chlorophyll values and canopy spectral changes were analyzed during fruit expansion period, fruit core-hardening period, oil conversion period and fruit ripening period. The correlation between the RVI, DVI and NDVI vegetation indices generated by any two-band combination and the canopy chlorophyll values in each growth period in the canopy spectral reflectance range of 400-1 000 nm were calculated, thus to determine the best sensitive band combination in each growth period. An estimation model of canopy chlorophyll values based on RVI, DVI and NDVI vegetation indices at different growth periods was established, and the accuracy of the estimation model was verified by the second year monitoring data. The canopy chlorophyll value estimation models of Juglans regia trees were established based on RVI, DVI and NDVI vegetation indices at different growth periods, and the accuracy of the estimation model was verified by the second year monitoring data. The results showed that:(1) The canopy chlorophyll value of Juglans regia canopy layer increased firstly and then decreased with the growth period. The coefficient of variation and standard deviation of canopy chlorophyll value in each growth period were significantly different. The canopy chlorophyll values was maximum in the fruit fat-conversion period, and minimum in the fruit expansion period;(2) From the fruit expansion period to the fruit ripening period, the canopy spectral reflectance in the visible light band was negatively correlated with the canopy chlorophyll values, and the negative correlation in the near infrared band from 760 to 1 000 nm became

关 键 词：核桃 生育期 冠层叶绿素含量 光谱反射率 估算模型 

分 类 号：S664.1[农业科学—果树学] S127[农业科学—园艺学]