Abstract:

To master the variation characteristics of heat injury of early rice in Guangxi, and provide decision-making support for rice cultivation and damage prevention, based on the meteorological data of 89 meteorological observatories and the corresponding geographic information data in Guangxi from 1958 to 2018, we analyzed the change characteristics of the time and spatial distribution of heat injury of early rice by GIS technology, M-K abrupt change analysis and Morlet wavelet analysis. The results showed that: (1) the incidence of heat injury of early rice in Guangxi showed an increasing trend from 1958 to 2018, the 1990s was a trough, while the 2010s was a period of high incidence;(2) the occurrence of heat injury of early rice in Guangxi increased sharply in 2009, except serious heat injury, there was an abrupt change in the occurrence of both mild and moderate heat injury;(3) the occurrence frequency of heat injury had a significant periodic change of about 18 years and 32 years, it was expected that heat injury would still be in a high incidence season for early rice in Guangxi after the year of 2018; (4) heat injury areas of early rice in Guangxi were mainly distributed in the valleys of Zuojiang River and Youjiang River, Guizhong Basin and Xijiang River - Xunjiang River - Yujiang River Basin. The occurrence frequency of heat injury in coastal areas was less than that in inland areas. The conclusions above could have important practical significance for realizing high, stable and optimal yield of rice.

Key words: rice, heat injury, GIS technology, temporal-spatio variation trend, abrupt change characteristics, Morlet wavelet