INFLUENCES OF ROOT PRUNING ON SHOOT GROWT H AND YIELD OF THE FIRST CROP IN MATURE TEA PLANTS

Different root pruning treatments in conjunction with shoot pruning an d the application of nitrogen and organic material were carried out on 18-year-old tea plants (Camellia sinensis (L.) O. Kuntze) in 1990. Th e pruning treatments consisted of: 1) light pruning every late August and application of organic material (conventional); 2) heavy root prun ing and application of heavy nitrogen and organic material only in lat e September 1990 (late September I); 3) heavy root pruning plus shoot pruning only in late August 1990 (late August II); 4) heavy root pruni ng plus shoot pruning and application of heavy nitrogen and organic ma terial only in late September 1990 (late September II); and 5) no prun ing (control). The influence of the root pruning treatments on shoot g rowth and yield in the first crop tea were studied from 1991 to 1995. For the late August I treatment, no reduction in shoot growth and yiel d was observed in the subsequent year, possibly because only small roo ts had been removed. Young shoot size and yield gradually decreased ev ery year thereafter. Late September I treatment caused yield to gradua lly increase from the second year, although slight yield reduction was noted in the first year. Late August II and late September II treatme nts failed to result in yields better than the control throughout the five years. The renewal of root systems by root pruning is believed to be an effective technique for regenerating tea plants and improving s hoot growth and yield in the first crop tea.