2016 Volume 2016 Issue 122 Pages 15-20
In Kuma, Kumamoto, owing to large variations in the inland climate, there is a concern of withering damage to wintering buds from lower winter temperatures than those in the major tea-producing areas. This study examined the danger of withering to wintering buds and the method of skiffing that could ensure a stable yield of the first tea crop.
In this study, which was over 2 years, 25-80 % of wintering buds in autumn skiffing suffered from cold injury and/or died. This implies that in the tea fields of Kuma, which were subjected to autumn skiffing, the damage to wintering buds was so large that it affected the yield of the first tea crop every year.
Damage to dead buds was observed 1.2-2.4 cm from the canopy surface. Parts of the wintering buds that were exposed to the canopy surface owing to autumn skiffing suffered cold injury, suggesting that damage to dead buds was up to several cm away from the canopy surface. In addition, the combination of preliminary autumn and spring skiffing resulted in a lower proportion of dead buds and cold injury than just autumn skiffing. In 2015, dead buds were within 3 cm of autumn preliminary skiffing although autumn preliminary skiffing was 3 cm higher than spring skiffing, which suggested that it is impossible to prevent withering of wintering buds by surface spring skiffing each year.
No difference was observed between the time of bud opening and spring or autumn skiffing. Although not statistically significant, spring skiffing tended to show 2-27% higher yields than autumn skiffing.
The combination of autumn preliminary skiffing in late October and spring skiffing 20 days before bud opening increased the yield of the first crop by 24% as compared to that autumn skiffing. Furthermore, assuming a timely harvest but late plucking date, the results suggested an additional yield increase of 5 cm autumn from preliminary skiffing.
In conclusion, preliminary autumn skiffing, which was done at 5 cm higher than skiffing in late October, and spring skiffing, which was done 20 days before bud opening, can increase the yield of first tea crop in Kuma.
