What kind of fertilizer is suitable for fruit trees during autumn fertilization?
I. Core Fertilizer for Fruit Trees in Autumn: Composted Organic Fertilizer
Composted organic fertilizer is the main fertilizer for autumn base fertilizer and cannot be replaced. All fruit trees should use organic fertilizer as the main component in autumn fertilization, accounting for more than 70% of the total base fertilizer amount throughout the year.
High-quality Composted Organic Fertilizers for Fruit Trees
1. Composted Sheep and Cow Manure: Mild in nature, with long-lasting fertilizer effect, high organic matter content, can effectively loosen compacted soil and improve soil aeration, suitable for most fruit trees such as apples, pears, peaches, citrus fruits, and grapes. It is risk-free for beginners and will not burn the roots.
2. Composted Farmyard Compost and Straw Fertilizer: Convenient to obtain raw materials, can improve soil aggregate structure, replenish soil organic matter, suitable for large-scale orchards, can continuously provide nutrients for fruit trees.
3. Commercially Composted Organic Fertilizer: Through high-temperature fermentation and sterilization, free of pathogens, insect eggs, and root burn risks, clean and convenient, suitable for courtyard fruit trees and densely planted orchards, adaptable to various large-scale planting scenarios.
Core Function of Organic Fertilizer
Improving soil, breaking soil compaction, enhancing soil water and nutrient retention capacity; slowly and continuously supplying nutrients, helping fruit trees accumulate wintering nutrition; promoting root growth, improving tree body's cold and drought resistance; improving fruit taste, reducing abnormal fruits, fundamentally improving fruit quality.
Prohibited Items
Do not use uncomposted raw manure or chicken manure! Raw manure will undergo secondary fermentation in the soil, generating high temperatures, directly burning the absorption roots of fruit trees, and carrying a large number of pathogens and insect eggs, aggravating the outbreak of diseases and pests in the following year, and causing soil salinization.
II. Essential Supplement Fertilizer: Compound Fertilizer (Balanced Type Dominant)
It is not recommended to use only nitrogen fertilizer in autumn fertilization, as it will cause fruit trees to grow excessively in autumn shoots, branches not aging, and wintering frost damage. Prefer balanced potassium sulfate compound fertilizer (nitrogen-phosphorus-potassium 15-15-15, 17-17-17), suitable for all fruit trees to use in autumn.
Main Functions
1. Supplement Phosphorus: Promote fruit bud differentiation and root germination, making the next year's fruit buds full and large, reducing the occurrence of years of abundance and scarcity.
2. Supplement Potassium: Strengthen the tree body, harden branches, improve the cold and drought resistance of fruit trees, and reserve nutrients for the expansion and sweetness of fruits in the following year.
3. Supplement Nitrogen: Mildly supplement the tree body's nutrition, avoid weak tree growth, prevent nutrient deficiency and yellow leaves, maintain balanced growth of the tree body.
III. Key Fertilizer for Quality Enhancement and Root Strengthening: Trace Element Fertilizer
Fruit tree nutrient deficiency is the main cause of yellow leaves, small leaves, fruit drop, cracking, and abnormal fruiting. If the soil is continuously applied with chemical fertilizers alone, it will lead to a lack of trace elements. Autumn is the best time to supplement trace elements, and the nutrients can be stored for a long time in the tree body.
Key supplementation of calcium, magnesium, boron, zinc, and iron:
- Boron and Zinc Fertilizer: Promote flower bud formation, stabilize fruiting, prevent problems of poor fruiting and low fruit set in the following year;
- Calcium and Magnesium Fertilizer: Prevent fruit cracking, bitter skin disease, and stem rot disease, enhance leaf photosynthesis, make the tree body stronger.
Trace element fertilizer does not need to be applied in large quantities each time, once a year in autumn is sufficient, effectively alleviating fruit tree nutrient deficiency diseases.
IV. Rooting Soil Improvement and Yield-Increasing Fertilizer: Biological Fertilizer
Biological fertilizer is a necessary fertilizer for improving the quality and yield of modern orchards, especially suitable for orchards with repeated cropping, compacted soil, saline-alkali soil, and old or weak trees.
Core Effects
1. Activate the soil and decompose the fixed nutrients in the soil, releasing phosphorus and potassium, and increasing the overall fertilizer utilization rate;
2. Inhibit harmful bacteria in the soil, reducing root rot, root damage, root knot nematode diseases, etc. in the root system;
3. Stimulate the growth of new roots in the trees, repair damaged root systems, and quickly rejuvenate weak and old trees.
V. Autumn Fruit Tree Golden Fertilization Combination Scheme (Universal Universal Formula)
This is a high-yield fertilization combination that has been verified in numerous orchards and is suitable for all deciduous and evergreen fruit trees such as apples, pears, peaches, plums, citrus, pomegranates, and grapes:
Composted organic fertilizer + balanced potassium sulfate compound fertilizer + micronutrient fertilizer + biological fertilizer
Usage Reference (Adult Bearing Trees)
1. Composted organic fertilizer: 20–80 pounds per tree (adjust according to tree age and tree crown size, reduce for young trees and increase for large trees);
2. Balanced compound fertilizer: 0.5–2 pounds per tree;
3. Micronutrient fertilizer: 0.2–0.5 pounds per tree;
4. Biological fertilizer: 0.3–1 pound per tree.
VI. Best Time for Autumn Fertilization and Core Taboos
Best Fertilization Time
September late - November early, before the fruit trees shed their leaves after the harvest is completed.
At this time, the ground temperature is high, the root system is active, nutrients are absorbed quickly and stored abundantly, and the fertilization effect is far better than winter or spring application. The earlier the fertilization, the more sufficient the tree's nutrient accumulation, and the better the growth and higher the yield in the following year.
Key Taboos
1. Do not apply shallowly: The fertilizer application depth should be maintained at 20–40 centimeters, away from the tree trunk and applied at the drip line of the tree crown, guiding the root system to grow downward to avoid root system floating and early tree decline;
2. Do not apply in a scattered manner: Do not apply fertilizer directly on the surface of the ground, as the nutrients will volatilize and lose effect almost completely;
3. Do not apply excessive nitrogen fertilizer: Avoid vigorous growth of autumn shoots, tender and weak branches, and easy winter damage due to cold;
4. Do not use uncomposted manure: To prevent root burn, rotting roots, and the occurrence of diseases and pests.
