How to fertilize grapes in winter?
Different types of grapes require different fertilizers at different growth stages. The fertilization should be matched and balanced according to the characteristics of fertilizer required at different growth periods and different fertilizers. The fertilizers consumed by grapes are nitrogen, phosphorus, potassium and calcium. After the grapes are harvested, a rejuvenating fertilizer should be applied in time to achieve the purpose of restoring the tree vigor. Apply 10-15 kilograms of urea and 2000 kilograms of agricultural fertilizer per mu. In the middle and late September when the root system of grapes is vigorous, it is important to apply the base fertilizer, and apply it after harvest to before and after the leaves fall. The application of base fertilizer is recommended for 1 kg of fruit and 4 kg of fertilizer. The base fertilizer is mainly organic fertilizer combined with phosphorus fertilizer and a small amount of nitrogen fertilizer. Special attention should be paid to the supplementary application of potassium fertilizer. When the base fertilizer is insufficient, extra-root topdressing is required. The ratio of nitrogen, phosphorus, and potassium is 2:1:2.4.
The method of fertilization mostly adopts strip ditch or radial ditch application. When digging the fertilization ditch, the distance from the main trunk is 50-70 cm and the depth is 30-40 cm. After the fertilizer is applied, the ditch is filled with soil.
How to prune the vine?
The pruning period of grapes in winter is 2-3 weeks after the plants are naturally deciduous and before bleeding, usually in the middle and late December. In general, the germination rate and seed setting rate of the bud eyes at the base of the parent branch of grapes are lower, while the middle and upper bud eyes are higher. For varieties with vigorous growth and low fruiting female shoots, medium and long shoots are mainly pruned; the flower buds at the lower part of weak branches are better differentiated, and short shoots are the main pruning method. For the pruning of Kyoho, Hongdi, and Qiuli grapes, the pruning method is mainly mid-top pruning, with a mixture of long and short shoots. For the pruning of the fruiting mother branches, 4-8 buds are generally left when using mid-shoot pruning; when short-shoot pruning is used, 2-3 buds are left, and when long-shoot pruning, 8-12 buds are left. For specific pruning, leave branches with full buds and tight scales, dense tissues, short internodes, large protrusions between nodes, deep purple in color and fully mature branches without pests and diseases. As for the number of cut residues of the resulting mother branches, it can be judged based on comprehensive factors such as variety characteristics, shelf characteristics, tree age, and yield. Generally, 8-10 fruiting mother branches are reserved per square meter on the shelf surface of the fence, and 6-8 fruiting mother branches per square meter on the shelf surface.
