Key Technical Points for Fine Post-Harvest Management of Greenhouse Nectarines

After the fruit of greenhouse nectarines is harvested, the tree vigor needs to be restored, and the quality of flower buds and tree structure for the following year must be taken into account. Therefore, soil, fertilizer and water management, pest and disease control, and shaping and pruning at this stage are crucial.

I. Post-Harvest Pruning

?? ?By the fruiting stage, the tree canopy has already formed within a unit area, and the space is basically filled. However, after the greenhouse covering is removed, the trees have the same growing time as those in the open field. If pruning is not done carefully, serious crowding and shading will inevitably result. At this time, the outside temperature is relatively low, and greenhouse peaches need a period of slow growth, which is exactly a good time for moderate heavy pruning.

1. Conventional pruning method ① Thin out slender weak branches, diseased and pest-infested branches, dead branches, drooping branches, overly dense branches and excessively vigorous outer branches to open up the light path, which is beneficial to flower bud differentiation. ② Retract branch groups, that is, retract branch groups originally composed of more than 4-6 fruiting branches into 2-4 branches, and cut back the vigorous branches within the group to 2-4 buds to promote new branch growth and cultivate new branch groups. ③ Large branch groups on the lower part of the canopy may droop after fruiting, so they should be propped and supported to restore their growth vigor. ④ In dense plantings, the phenomenon of strong top and weak bottom often occurs. At this time, the vigorous upper branches should be heavily pruned, removing the strong and keeping the weak, to inhibit growth.

2. Heavy pruning method ① For high-density cultivation using the trunk form and "Y" form, after fruit harvest, heavily retract the branch groups to 2-3 buds at the base (about 5-10 cm long), so that single-bud branches or latent buds at the base sprout and grow around the trunk and main branches. When new shoots grow to 30 cm, spray the leaves with 15% paclobutrazol at 100-300 times dilution 2-3 times, and later spray monopotassium phosphate to promote flower bud formation. ② Heavy retraction can be carried out in steps: first, prune one side first, and prune the other side 1 week later; second, prune the lower branches, and prune the upper branches 1 week later, but part of the light-blocking branches on the upper part should first be thinned out, especially when the top is strong and the bottom is weak, part of the upper branches should be thinned out to promote sprouting on the lower part. ③ Each heavy pruning should leave a small number of fine branches with intact leaves as a source for producing organic nutrients, and they must not all be cut bare at once. The branch-breaking method can also be used, that is, heavily prune part of the branches and break part of the branches, then cut them off after new buds sprout about 10 cm.

?II. Topdressing and Base Fertilizer Application

?? ?In combination with heavy pruning after harvest, carry out one round of trench fertilization. Dig small trenches 50 cm long, 30 cm wide and 25-30 cm deep between the rows, with the trench located between two trees. If the plant and row spacing is relatively large after thinning, the fertilization trench can be larger. When the row spacing is 2-3 m, a continuous trench can be dug. Apply decomposed organic fertilizer in the trench, then mix in nitrogen, phosphorus and potassium compound fertilizer, 0.25-0.5 kg per tree.