Research on Impact Model and Grading Indicators of Rice Heat Damage Based on Hours Thermal Accumulated Temperature
[Objective]The impact model and grading indicators of rice heat damage based on hours thermal accumulated temperature were constructed to provide basis for carrying out refined services of reducing the rice heat damage.[Method]A rice field experiment with covering transparent film for improving temperature was carried out in Huaihua of Hunan from 2021 to 2022.Taking Y Liangyou 911 as the experimental variety,combining with hourly air temperature data,using quadratic equation fitting,LSD analysis of variance significance and correlation analysis,the model and grading indicators for quantitative assessment of high-temperature impacts on the fruiting rate from the booting stage to maturity stage of one-season rice were screened and established based on the hours thermal accumulated temperature at different high temperature thresholds,and was validated with independent samples.[Result]The reduction of rice fruiting rate was closely related to the hours thermal accumulated temperature of high-temperature threshold from 35-40℃,with the highest correlation with the 35℃(P＜0.001),followed by 36℃(P＜0.005)and 37℃(P＜0.010).The 2%,4%,and 8%reduction in fruiting rate were the thresholds causing light,medium,and severe heat damage,respectively.The high-temperature thresholds and the lower limit of their corresponding hours thermal accumulated temperature for light,medium,and severe heat damage was 35℃,146℃·h,196℃·h and 365℃·h;36℃,112℃·h,176℃·h and 334℃·h;37℃,85℃·h,140℃·h and 270℃·h,respectively.The model and indicators validation results had good agreement with the measurements,among which the model with 35℃ as the high temperature threshold had the lowest mean absolute error(MAE),root mean square error(RMSE)and the highest correlation coefficient(r),and the index validation results had the best consistency with the measured data.[Conclusion]The model for rice heat damage and grading indicators based on hourly thermal accumulated temperature indexes can well reflect the actual situation of fruiting rate affected by high temperature,and can be applied to the monitoring and early warning of heat damage in rice production,disaster prevention and mitigation services.
high temperaturehours thermal accumulated temperatureone-season ricegrowth periodquantita-tive assessment modelgrading indicators for heat damageY Liangyou 911
NETL
NSTL
万方数据
