Abstract
Covering methods with some kinds of grasses and chemical textures were studied from 1973 to 1975 for the effectiveness in preventing the bark splitting injury that is a kind of cold injury caused by frost and is mostly found in young tea plants grown in warm regions.
1. It was proved that all the covering methods protected young tea plants from being exposed to extremely low temperature in occurrence time and consequently reduced the damage of the bark splitting injury.
2. The type of grasses that are tolerable to a low temperature, such as oats, showed greater effect than sorghum or crotalaria which is tender to a low temperature.
3. The covering method with oats showed great effect in the case that they had perfectly covered the young tea plants, when the amount of insolation was 40-60cal/cm2, before the occurrence season of the bark splitting injury.
The best result was obtainded in the case that the seeds fo about 4kg/10a had been sowed in belt on both sides about 30cm apart from a row of the tea plants in late August.
4. Straw mat and chemical textures (BB-tex, Tuffubel and cheesecloth) used as covering materials were also effective to prevent the injury but the covering effect of the chemical textures was smaller than that of the straw mat.
5. The covering method with oats showed greater effect than any other methods probably because the method kept low the maximum air temperature under tea plants' crown and controlled the supply of moisture and nitrogen in soil to tea plants through competition.
