Which is better, organic fertilizer or chemical fertilizer?

Let me give you a straightforward conclusion right away: 
When it comes to "growing fast and having high yields", chemical fertilizers are the clear winners. 
When it comes to the reasons for the fruit being sweet, the soil being fertile, the trees having a long lifespan, and the necessity of selling them for money, organic fertilizer is simply unbeatable. 
To truly cultivate an orchard well, both organic and chemical fertilizers must be used together; neither can be dispensed with. **

Let me explain it to you clearly: 

I. Advantages of Chemical Fertilizers (Quick Results in the Short Term) 

It takes effect the fastest, turning green and growing vigorously in just a few days. 
Pure nutrients, strong effect, and fast fruit expansion speed. 
Low cost, small amount used, and convenient. 

Disadvantages: 

The more soil is used, the more it becomes compacted and hard. 
The fruit is big but not sweet, insipid and tasteless. 
Trees with excessive vitality are prone to illness and oozing sap. 
If only chemical fertilizers are used for a long time, the trees will age quickly and the phenomenon of alternate bearing will be severe.

II. Advantages of Organic Fertilizer (Long-term Quality Assurance) 

Improve the soil and it will become looser and looser with each planting. 
The fruit is sweet, fragrant, has a good color and fetches a high price. 
Strong root system, stable tree growth, and few diseases. 
It yields steadily every year without alternate years of high and low production. 

Disadvantages: 

It takes a long time to show effect, and it will take 1 to 3 months to be effective. 
Large in quantity and labor-intensive. 
Its fertility is not as strong as that of chemical fertilizers. 

III. The Most Scientific Use of Orchards (How Experts Do It) 

Base fertilizer (in autumn): mainly organic fertilizer 

- 70% well-fermented manure (sheep manure/chicken manure) 
- 20% cake fertilizer (peanut cake/rapeseed cake) 
10% compound fertilizer 

Function: Nourish roots, promote flower bud formation, and ensure large and sweet fruits the following year. 

Fruit expansion period (summer): mainly chemical fertilizers 

High-potassium compound fertilizer / Potassium sulfate 
Spray potassium dihydrogen phosphate on the leaves in coordination. 

Function: Rapid fruit expansion, increased yield, enhanced sweetness

IV. Summary in the Briefest Form 

To grow strong trees, have fertile soil and produce sweet fruits for high prices → Organic fertilizer cannot be lacking 
If you want to grow trees quickly, produce fruits quickly and achieve high yields → Chemical fertilizers must be used 
The most efficient model of the orchard: 
Organic fertilizer as the base + chemical fertilizer for top-dressing = high yield, sweet taste and stable performance