基于气流屏障下的茶园低温冻害防控研究

Deterrence of Freeze-injury on Tea Bushes Using Airflow Barriers at Plantations

为应对极端低温天气对江西茶区的困扰和威胁,探索科学有效的茶园冻害减灾避灾技术措施,本研究设置围挡措施,通过阻碍冷空气的平流运动对茶树叶片的直接接触,分析比较不同处理温度变化和冻害差异,探讨冻害影响因子之间的关联性、贡献率,并计算冻害发生阈值。结果表明:与对照相比,围布与围布+膜处理可以有效减少低温(≤0℃)发生天数、持续时间以及负积温,发生天数减少1~3 d,持续时间减少10.16%~17.11%,负积温下降5.72%~20.23%;可以缩小空气温度的波动范围,日较差降幅12.08%~18.64%;可以减轻茶树低温冻害,受冻率下降了2.11%~8.0%。相关性分析表明,茶树受冻率与平均日最低温度、极端日最低温度、平均日温度呈极显著负相关(P<0.01),与日低温持续时间、日低温积温呈极显著正相关(P<0.01),与平均日较差不相关(P>0.05)。主成分分析得出,平均日最低温度、平均日温度、日低温持续时间为低温冻害主导因子,贡献率为89.69%。此外,通过曲线拟合计算出10%冻害发生率的平均日最低温度阈值为-0.77℃。综上所述,围挡措施能有效缓解茶园冻害,围布+膜是当前茶园冻害预防值得推广的技术。

To deter the threat of injuries by subfreezing temperature in winter on tea bushes at plantations in Jiangxi,means to physically alter the airflow by using barriers was investigated.Barrier materials,such as cloth and film,were used to block or divert cold airflow in winter to minimize direct contact of the plants with subfreezing temperature.Deterrence effect and contribution rate of the treatments on freeze-injury of plants were determined,and threshold temperature of injury calculated.Compared with control,the wrapping or the wrapping+filming treatment effectively reduced the number of days,duration,and accumulation of subfreezing temperature(≤0℃)to which the tea bushes were exposed.The treatments reduced the days of subfreezing temperature surrounding the bushes by 1~3 d,the duration by 10.16%~17.11%,and the accumulated subfreezing temperature by 5.72%~20.23%.The range of daily air temperature fluctuation also declined by 12.08%~18.64%,and the freeze-injury percentage of tea plants by 2.11~8.08.The rate of freeze-injury on the plants inversely correlated to the average lowest daily temperature,extremely low daily temperature,and average daily temperature(P<0.01),while positively to the duration of daily subfreezing temperature and daily accumulated subfreezing temperature(P<0.01),but not to the average daily temperature fluctuation range(P>0.05).The principal component analysis showed the major factors that affected the plant freeze-injury to be the average lowest daily temperature,average daily temperature,and subfreezing temperature duration which comprised a combined contribution rate of 89.69%.The average threshold of the lowest daily temperature that caused 10%injury incidence was-0.77℃,as calculated by curve fitting.The experimental airflow barrier treatments appeared effective in minimizing subfreezing temperature-induced injury on tea plants.The wrapping+filming method could be implemented at plantations to reduce potential damage to the tea bushes in winter.