Abstract:

 Clarifying the spatiotemporal characteristics of cold vortex−induced chilling injury during the booting stage of cold−region rice and the resulting yield losses, as well as analyzing the influence of cold vortex−type weather on rice yield formation, can provide meteorological references for the high−quality and safe production of cold−region rice. Using daily meteorological data and rice yield data from 65 meteorological stations in the rice−growing area of Heilongjiang province from 1964 to 2021, and based on the national standards of the People's Republic of China, authors identified obstacle−type low−temperature cold damage (referred to as cold vortex−type cold damage) caused by persistent northeast cold vortex activity during the rice booting stage. Using mathematical statistical methods, the occurrence patterns and spatiotemporal evolution characteristics of cold vortex−type chilling injury were analyzed and constructed a model to assess yield losses of rice due to cold vortex-type chilling injury. The results showed that a total of 223 occurrences of cold vortex-type chilling injury were recorded in the study area, with peak periods in the 1980s and 2000s. Spatially, there were significant regional differences, with more occurrences in the north and east compared to the south and west. At stations experiencing mild chilling injury, rice yield losses ranged from 3.4% to 9.2%, while moderate and severe chilling injury led to yield losses of 7.9% to 16.0% and 21.1% to 27.6%, respectively. This demonstrates that the greater the severity of cold vortex−induced chilling damage, the higher the yield reduction. The negative accumulated temperature (the accumulated temperature sums during the booting stage of rice, when the daily average temperature fell below the critical growth temperature) during the cold−vortex−induced chilling injury period was significantly correlated with the relative meteorological yield of rice (P<0.01). Within a specific range of negative accumulated temperature (−7.3℃·d to −0.6℃·d), with each 1℃·d decrease in negative accumulated temperature reducing relative meteorological yield by approximately 2.0, 4.4 and 3.5 percentage points in the western, central, and eastern regions, respectively. Overall, the greater the accumulation of negative temperature sums caused by cold vortex−type chilling injury, the lower the relative meteorological yield of rice.

Key words: Northeast cold vortex, Obstacle?type chilling injury, Negative accumulated temperature, Yield loss