Reasonable summer topdressing for fruit trees helps you achieve high yields

Fruit trees grow fast in summer, and their roots are exactly at the stage when they need guaranteed fertilizer and water. During this period, nutrient deficiency is prone to occur, and at this time reasonable summer topdressing for fruit trees can promote high yields!

1. Timing and types of summer topdressing for fruit trees

In early to mid-June, topdressing should mainly be phosphorus, to enlarge young fruit and plump up flower buds; from July to August, topdressing should mainly be potassium, with an obvious increase in yield and bright fruit color. Seize the two best opportunities for topdressing, the critical nutrient period of the fruit trees and the fruit enlargement period, and this year the fruit will be large and the yield high, while next year the flower buds will be plump and fruit set abundant.

For topdressing at the critical nutrient period, the best time is from early to late June. During this period flower buds begin to differentiate and young fruit rapidly expand. What most needs to be supplemented at this stage is phosphorus, which can plump up the branches, improve leaf function, and increase the amount of nutrients produced and exported by the leaves. For topdressing at the fruit enlargement period, the best time is from mid-to-late July to early August. During this period the fruit trees have the strongest ability to absorb nutrients and the highest fertilizer use efficiency. According to the growth and development characteristics of fruit trees, this period should focus on phosphorus and potassium fertilizers, especially the supplement of potassium.

2. Summer topdressing methods for fruit trees

Summer topdressing for fruit trees has the effect of promoting fruit enlargement and flower bud differentiation. Topdressing methods include root application under the tree and foliar spraying.

For root topdressing, summer topdressing for fruit trees should mainly use phosphorus and potassium chemical fertilizers, together with a small amount of nitrogen fertilizer. The amount of topdressing depends on tree species, tree age, fruit load and the status of base fertilizer. For young trees that have not yet entered the fruiting stage, 0.2-0.25 kg of phosphorus and potassium chemical fertilizers can be applied per tree. For general large fruiting trees, apply 2.5-3 kg of superphosphate, 10-15 kg of plant ash, and 2 kg of ammonium sulfate per tree. The topdressing method is to dig circular holes from the vertical line of the tree canopy inward to 1 m, with a hole spacing of 30-40 cm and a hole depth of 15-20 cm, then cover with soil after application. Orchards with the conditions should irrigate after topdressing.

For foliar spraying, carrying out foliar spraying during the fruit enlargement period has the effect of strengthening tree vigor, promoting fruit enlargement, and improving quality. The spray concentrations are 0.2% ammonium sulfate, 0.3%-0.5% urea, 0.3% potassium sulfate, 1%-3% superphosphate, and 0.3% monopotassium phosphate. Foliar spraying on fruit trees in mountainous areas has an even better effect.

3. Precautions for summer topdressing of fruit trees

1. First, it is necessary to know that fruit trees absorb nutrients mainly through the root hairs in the root system. Therefore, applying fertilizer in the area where root hairs are concentrated can improve fertilizer use efficiency and prompt the fruit trees to grow early and quickly, increasing both yield and income.

2. It should mainly be applied at the edge of the tree canopy projection or slightly farther out, and not too close to the trunk, because near the trunk there are thick large roots and fewer fine roots and root hairs, which is not conducive to fertilizer absorption.

3. Fertilization should follow the principles below:

(1) Fruit trees with deep root distribution should be fertilized appropriately deeply, and vice versa shallowly.

(2) Organic fertilizer decomposes relatively slowly but has a longer fertilizer supply period, so it can be applied deeply; chemical fertilizer has greater mobility, so it can be applied shallowly.

(3) If organic fertilizer is applied to deep-rooted fruit trees such as pear trees, the depth should be 40-60 cm, while if organic fertilizer is applied to shallow-rooted fruit trees such as plum trees, the depth should be 30-40 cm. After fertilization, a new high-lipid film can be sprayed to improve fertilizer efficiency.

4. For orchards with closed rows or dense planting, shallow application can be carried out between rows and between plants, preferably without injuring or with as little injury as possible to the large roots, so as to fully exert fertilizer efficiency, improve fertilizer use efficiency, and achieve the goal of increasing yield and income.