Analysis of climatic resources and drought characteristics during rice growth stages with

different sowing dates in Chengdu plain：A case study of Guanghan

LIAO Chengrui1，3， CHEN Yongren2， XIAO Tiangui3

（1. Guanghan Meteorological Bureau of Sichuan Province， Guanghan 618300， Sichuan， China；

2. Meteorological Disaster Defense Technology Center of Sichuan Province， Chengdu 610072， China；

3. Chengdu University of Information Technology， Chengdu 610225， China）

Abstract： As a major rice-producing area in Southwest China, the Chengdu Plain has faced increasingly severe drought problems in recent years. In order to determine the most suitable sowing date for rice in this region and improve the drought resistance, this paper takes Guanghan area as an example, and adopts the climate tendency rate method to analyze the characteristics of climate resources at the rice growth stages for different sowing dates from 1991 to 2020, and evaluates the degree of drought at different growth stages of rice at growth stages by using the Crop Water Deficit Index (CWDI). The results show that the climatic characteristics of rice for different sowing dates in the study area over the past 30 years showed a trend of decreasing sunshine, increasing mean daily temperature and increasing precipitation. With the delay in sowing, the number of sunshine during the whole life cycle of rice decreased, and the average daily temperature and precipitation both increased. The CWDI values gradually decreased with rice development, and the water deficit rate was higher at the first and middle stages for each sowing date. Light and moderate drought, followed by severe drought, and exceptional drought were observed during the growing stages of rice for different sowing dates. From late March to early April was the most suitable period for rice sowing in the study area, and drought-resistant varieties should be selected for sowing in early and mid-March, while sowing in mid-to late-April people should guard against the effects of severe drought on the water demand period of the crop.