How to Prune Grapevines During the Fruitbearing Stage
Pruning grapevines directly affects the quality and yield of the fruit, especially during the fruitbearing stage, precise control of pruning is necessary. Scientific pruning not only optimizes the ventilation and light conditions of the plant but also distributes nutrients supply reasonably. This article will systematically analyze the pruning essentials during the fruitbearing stage and the two key stages of winter.
Key Techniques for Pruning Grapevines During the Fruitbearing Stage
1. Principles of Pruning Branches
Retain robust fruit-bearing branches with diameters of 0.8-1.2 cm, using the "Three-Cut Method": first cut the withered and yellow branches, second cut the dense and crossed branches, third cut the weak and fruitless branches. Pay attention to retaining the main vines with evenly spaced buds, leaving 4-6 buds on each fruit-bearing branch, ensuring the total number of buds per plant is controlled between 25-30.
2. Techniques for Thinning Fruit
Follow the "Three Remove and Three Retain" principle: remove deformed fruit, remove sun-scalded clusters, and remove clusters affected by diseases and pests. Retain 1-2 clusters per fruit-bearing branch, with each cluster containing 50-80 grapes. Use a flat-cut pruning shears, leaving a 0.5 cm stub of the fruit stem to prevent the invasion of pathogens.
Winter Pruning Strategy for Grapevines
The best window period for pruning is 15 days after defoliation to 20 days before germination. Use the "Combination of Long and Short Shoots Pruning Method": extend the main vine by 8-12 buds for long pruning, and cut the fruit-bearing branches by 2-4 buds for short pruning. Focus on removing weak branches with diameters less than 0.6 cm, maintain a spacing of 20-25 cm between the branches, ensuring 12-15 fruiting units per square meter of trellis.
Through double pruning management during the fruitbearing stage and the dormant period, the annual yield of grapevines can be increased by over 30%. It is recommended to coordinate with water and fertilizer control, supplement phosphorus and potassium fertilizers promptly after pruning, use 0.3% potassium dihydrogen phosphate foliar spray to promote wound healing and flower bud differentiation. Regularly check the pruning results and establish pruning records to document the growth dynamics of the branches.