Determining the planting year of navel orange trees in mountainous and hilly areas of southern China:a remote sensing based method  

作　　者：LEI Juncheng WANG Sha WANG Yuandong LUO Wei 

机构地区：[1]School of Geography and Environmental Engineering,Gannan Normal University,Ganzhou 341000,China [2]School of Chemistry and Chemical Engineering,Gannan Normal University,Ganzhou 341000,China

出　　处：《Journal of Mountain Science》2024年第10期3293-3305,共13页山地科学学报（英文）

基　　金：sponsored by the Science and Technology Project of the Education Department of Jiangxi Province [Grant No. GJJ211427];Open project of discipline construction of the School of Geography and Environmental Engineering of Gannan Normal University;National Natural Science Foundation of China [Grant No. 42161019]

摘　　要：Remote sensing has demonstrated validity in determining the planting year of deciduous fruit trees;however,its effectiveness in ascertaining the planting year of evergreen fruit trees remains unverified.Furthermore,the sources of error associated with using remote sensing to determine the planting year of fruit trees remain unclear.This study investigates several cultivated sweet orange(Citrus sinensis)varieties,which are extensively cultivated throughout subtropical China.We analyzed Landsat time series data from 132 navel orange orchards in Gannan,covering the period from 1993 to 2021.For each orchard,Google Earth Engine was employed to extract three vegetation indices—Enhanced Vegetation Index(EVI),Normalized Difference Vegetation Index(NDVI),and Normalized Burn Ratio(NBR)—for each available date,thereby generating three distinct vegetation index time series.The planting year of navel orange trees was identified based on abrupt changes observed in these time series.The principal sources of error in determining the planting year were investigated using the Wilcoxon signed-rank test,Spearman's correlation analysis,and Kruskal-Wallis H test.Key findings include:(1)Following the planting of navel orange trees,EVI,NDVI,and NBR exhibited fluctuations and a gradual increase over time,peaking approximately 10 to 15 years later.(2)The vegetation index time series derived from Landsat imagery effectively determined the planting year of evergreen navel orange trees in orchards,even within highly fragmented landscapes.Among these indices,NDVI and NBR time series outperformed the EVI time series.Specifically,the average determination errors for EVI,NDVI,and NBR time series were 6.4,1.8,and 2.8 years,respectively.(3)Major sources of error included the methods used to construct the time series,the selection of vegetation indices,and the orchard management practices.Overall,this study provides a viable method for determining the planting year of evergreen navel orange trees in fragmented landscapes and offers insights int

关 键 词：Time series Remote sensing Google Earth Engine Gannan SUBTROPICS 

分 类 号：S666.4[农业科学—果树学] S127[农业科学—园艺学]