Deterrence of Freeze-injuryon Tea Bushes Using Airflow Barriers
at Plantations

To deter the threat of injuries bysubfreezingtemperature in winter on tea bushes at plantations in Jiangxi,means to physicallyalter the airflow by using barriers was investigated.Barrier materials, such ascloth and film, were used to block or divert cold airflow in winter to minimizedirect contactof the plants with subfreezing temperature.Deterrence effect andcontribution rate of the treatmentson freeze-injury of plants were determined,and threshold temperature of injury calculated. Compared with control, thewrapping or the wrapping+filming treatment effectively reduced the number ofdays, duration, and accumulation of subfreezing temperature (≤0℃) to which the tea bushes were exposed. Thetreatments reduced the days of subfreezing temperature surrounding the bushesby 1-3d, the duration by 10.16%~17.11%, and the accumulated subfreezingtemperature by 5.72%-20.23%. Therange of daily air temperature fluctuation alsodeclined by 12.08%~18.64%, and the freeze-injury percentage of tea plants by2.11-8.08.The rate of freeze-injury on the plantsinversely correlated to theaverage lowest daily temperature, extremelylow daily temperature, and averagedaily temperature (p＜0.01), while positively tothe duration of daily subfreezing temperature and daily accumulated subfreezingtemperature (p＜0.01), but not to the averagedaily temperature fluctuation range (p＞0.05). Theprincipal component analysis showed the major factors that affected the plantfreeze-injury to be the average lowest daily temperature, average dailytemperature, and subfreezing temperature duration which comprised a combinedcontribution rate of 89.69%. The average threshold of the lowest dailytemperature that caused 10% injury incidence was -0.77 ℃, as calculated by curve fitting.The experimental airflow barriertreatments appeared effective inminimizingsubfreezing temperature-inducedinjury on tea plants. The wrapping+filming method could be implemented atplantations to reduce potential damage to the tea bushes in winter.