Assessing winter oilseed rape freeze injury based on Chinese HJ remote sensing data

作     者：Bao SHE Jing-feng HUANG Rui-fang GUO Hong-bin WANG Jing WANG 

作者机构：Institute of Agricultural Remote Sensing and Information Technology Application College of Environmental and Resource SciencesZhejiang University Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Feidong Agricultural Technology Extension Center 

出 版 物：《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 (浙江大学学报（英文版）B辑（生物医学与生物技术）)

年 卷 期：2015年第16卷第2期

页      面：131-144页

核心收录：

学科分类：09[农学] 0904[农学-植物保护] 0901[农学-作物学] 

基　　金：Project supported by the National Natural Science Foundation of China(No.41171276) 

主　　题：Brassica napus Freeze injury Remote sensing Crop monitoring HJ-CCD 

摘      要：The winter oilseed rape（Brassica napus L.） accounts for about 90% of the total acreage of oilseed rape in China. However, it suffers the risk of freeze injury during the winter. In this study, we used Chinese HJ-1A/1B CCD sensors, which have a revisit frequency of 2 d as well as 30 m spatial resolution, to monitor the freeze injury of oilseed rape. Mahalanobis distance-derived growing regions in a normal year were taken as the benchmark, and a mask method was applied to obtain the growing regions in the 2010–2011 growing season. The normalized difference vegetation index（NDVI） was chosen as the indicator of the degree of damage. The amount of crop damage was determined from the difference in the NDVI before and after the freeze. There was spatial variability in the amount of crop damage, so we examined three factors that may affect the degree of freeze injury： terrain, soil moisture, and crop growth before the freeze. The results showed that all these factors were significantly correlated with freeze injury degree（P0.01, two-tailed）. The damage was generally more serious in low-lying and drought-prone areas; in addition, oilseed rape planted on south- and west-oriented facing slopes and those with luxuriant growth status tended to be more susceptible to freeze injury. Furthermore, land surface temperature（LST） of the coldest day, soil moisture, pre-freeze growth and altitude were in descending order of importance in determining the degree of damage. The findings proposed in this paper would be helpful in understanding the occurrence and severity distribution of oilseed rape freeze injury under certain natural or vegetation conditions, and thus help in mitigation of this kind of meteorological disaster in southern China.