How are light pruning and deep pruning carried out on mature tea plants?

Light pruning

(1) Light pruning: The purpose of light pruning is to promote the sprouting and growth of tea buds, increase the production density, and strengthen the vigor of the tea plant. It is an indispensable technical measure for creating and maintaining a good plucking surface. The degree of light pruning is measured by cutting off 3-5 cm of branches and leaves from the top of the canopy, or alternatively by cutting off the previous year's autumn shoots while leaving the summer shoots. For tea plants of the small and medium-leaf varieties, the light pruning form is best done by cutting the canopy surface into an arc shape, as this can increase the width of the plucking span and is beneficial for raising the per-unit yield. For tea plants in the young and mature stages, light pruning can be carried out once a year or every other year, each time raising the cut 2-3 cm above the original cut.

(2) Deep pruning: After many years of plucking and light pruning, dense and weak branches form on the plucking surface; these are what are commonly called "chicken-claw branches," and the yield and quality of the tea gradually decline. To renew the plucking surface of the tea plant, deep pruning techniques can be used, cutting away the dense and weak layer of "chicken-claw branches" so that the tea plant sends out new shoots again, improving the sprouting capacity of the tea plant and extending the number of years of high and stable yield. Deep pruning should cut off 1o 15 cm of branches and tips from the canopy surface; too shallow a cut cannot achieve the purpose of renewing the plucking surface. After deep pruning, the tea plant should still be lightly pruned once a year or every other year, appropriately leaving more new leaves, and the plucking surface should be re-established.

Deep pruning

3. Heavy pruning and collar pruning of senescent tea plants. For senescent tea plants, heavy pruning and collar pruning can be used to re-establish the canopy, rejuvenate the tree vigor, and achieve high yield and quality.

(1) Heavy pruning: The object of heavy pruning is semi-senescent tea plants and those that have declined before their time. The degree of heavy pruning must be properly controlled; too light a cut gives no significant effect, while too heavy a cut means slow recovery and affects yield. Generally, for tea plants over 80 cm tall, the retained height can be kept at 35-40 cm; for some low-growing tea plants, it is best to cut off 1/2 of the original plant height. After heavy pruning, the tea plant should present a level form. The pruning period is best before the spring tea, which is favorable for recovery of tree vigor. If part of the high-grade tea is to be plucked during the spring tea period to increase economic returns, it can also be pruned after the spring tea.

(2) Collar pruning: The purpose of collar pruning is the same as that of heavy pruning: it is a more thorough pruning technique for transforming the canopy. The object of collar pruning is extremely senescent tea plants, so as to re-establish a completely new canopy. However, tea gardens after collar pruning generally have some impact on yield in the short term, and the degree of impact is related to the foundation of the tea garden and the level of cultivation and management after transformation. The impact is greater where the original per-unit yield was higher or where management is neglected after transformation; the impact is small where the original per-unit yield was low or where management is strengthened after transformation, and cases where the yield in the second year after transformation exceeds the original level are not uncommon in production. The collar pruning height for senescent tea gardens is generally best at 5 cm above the ground. The collar pruning period is the same as that for heavy pruning. The collar pruning tool can be collar pruning shears or a collar pruning machine. The cut should be made as smooth as possible and slightly slanted. Tea plant pruning requires the cooperation of other technical measures for the effect to be significant, such as strengthening fertilizer and water management, carrying out rational plucking suited to each plant, and doing a good job of tea plant pest and disease control, all of which are extremely important.