Incidence characteristics and influencing factors of sunburn on tea trees in tea gardens of Meitan,Guizhou

【Objective】To explore the incidence characteristics and influencing factors of tea tree sunburn in tea gardens of Meitan,Guizhou,and to provide theoretical references for the regional development of drought mitigation in tea gardens. 【Method】A typical sample plot survey method was used to investigate the incidence characteristics of tea tree sunburn in 150 tea gardens in Meitan,Guizhou,to analyze the effects of factors such as tea tree characteristics,cultivation management and topographic conditions on the incidence characteristics of tea tree sunburn; a random forest(RF) model was used to study the relative importance of the effects of various factors on the incidence degree of tea tree sunburn. 【Result】The incidence rate of sunburn in tea gardens in Meitan,Guizhou was as high as 85.3%,and the average value of the incidence degree was 30.8%. There were differences in the incidence degree of sunburn among different tea cultivars,among which Fuding Dabaicha had the highest incidence degree of sunburn,with a mean value of 45.9%,which was significantly higher than that of Qianmei 601,Qianmei 502 and Qianmei 809(P<0.05,the same below). The land use manner before tea planting had significant effect on the incidence of sunburn,among which the land use of paddy fields had the highest incidence of sunburn,with a mean value of 52.9%,followed by drylands,forest lands and barren grasslands.Compared with the tea garden without shade trees,the incidence of sunburn in tea gardens planted with shade trees was reduced by 13.3%(absolute value,the same below),and the degree of incidence was significantly reduced by 10.8%. The degree of incidence of tea tree sunburn in tea gardens at different altitudes varied significantly,with the average value of the degree of incidence in tea gardens with altitude of ≤820 m as 46.3%,significantly higher than that of tea gardens with altitude >820 m. The incidence degree of sunburn in tea gardens with different terrain positions was the highest in gully,with an average value of 50.8%,and the lowest in slope waist,with an average value of 24.6%. The incidence of sunburn in tea gardens with different slopes was the highest in flat,with an average value of 40.9%,and the lowest in steep slopes,with an average value of only 10.3%. Random forest model analysis showed that the primary factor affecting the incidence of tea tree sunburn was land use manner before tea planting,which had the highest relative importance of 23.9%,followed by tea tree cultivars. 【Conclusion】Tea tree sunburn disease incidence characteristics are affected by land use manner before tea planting,tea cultivars,terrain slope,altitude,terrain position and shade trees,of which the land use before tea planting is the primary influence factors. Drought prevention should be strengthened in tea gardens with cultivars of Fuding Dabaicha,land use manner of paddy fields before tea planting,low altitude in the region,in the gully and on flat slope,and appropriate planting of shade trees can effectively mitigate the impact of drought and high temperature on tea trees.