Current issues in grape fertilization

1. Long-term reliance on chemical fertilizers has resulted in a severe shortage of organic fertilizers.
Long-term, excessive application of chemical fertilizers can lead to soil compaction and degradation, reducing the soil’s organic matter content, microbial activity, and humic acid levels, thereby lowering fertilizer use efficiency.
Long-term reliance on chemical fertilizers, with little or no organic fertilizer application, leads to progressively declining fruit quality, impaired fruit coloration, diminished pulp flavor, widespread physiological disorders, reduced storage life, and a lower proportion of marketable fruits.
2. Overemphasis on nitrogen fertilizer application and underemphasis on potassium fertilizer application.
Excessive application of nitrogen fertilizer can severely impair the grapevine’s uptake of calcium, potassium, and other nutrients, leading to nutritional imbalances, underdeveloped bud eyes, thin and large leaves, delayed cessation of shoot growth, difficulty in flower‑bud formation, an increase in physiological disorders, reduced fruit quality, diminished plant vigor, and a heightened incidence of diseases such as sour rot and powdery mildew.
Potassium plays a catalytic role in grapevine metabolism, enhancing photosynthesis, regulating stomatal opening and closing, reducing transpiration, and improving plant stress resistance. It also exerts a crucial influence on fruit quality development by promoting fruit enlargement, increasing sugar content, facilitating coloration, and elevating overall fruit quality. Conversely, insufficient potassium application can weaken tree vigor, diminish stress tolerance, stunt new shoot growth, and cause premature cessation of elongation; leaf margins may turn chlorotic and yellow, often curling upward, then gradually turning brown and scorching, ultimately leading to early leaf abscission.
3. Emphasizing the application of macronutrients while neglecting meso- and micronutrients.
Grapes are perennial fruit trees that, once established, remain productive for many years. During fertilization, growers often focus solely on supplying macronutrients such as nitrogen, phosphorus, and potassium, while rarely applying fertilizers containing secondary and micronutrients.
This often leads to soil nutrient imbalances, low fertilizer use efficiency, severe micronutrient deficiencies, an increase in physiological disorders, and a gradual decline in grape quality, making it difficult to raise the proportion of high‑quality fruit. Therefore, when applying fertilizers, it is essential not only to replenish macronutrients in a timely manner but also to supplement meso‑ and micronutrients appropriately.
4. Uncertainty and arbitrariness in the timing of fertilization
The timing of fertilizer application for fruit trees is closely linked to their growth cycle. Fruit growers often rely on subjective judgment to determine the fertilization schedule, failing to align it with the crop’s nutrient‑requirement patterns. This approach not only undermines the intended benefits of fertilization but may also result in production losses.
In recent years, orchards have often delayed the application of base fertilizer until spring, preventing its nutrients from being promptly available during the tree’s peak demand period. This delay in nutrient release promotes vegetative growth, causing new shoots to fail to cease growth on time or even to re‑sprout, thereby inhibiting reproductive development and adversely affecting the tree’s growth and fruiting in the following year. Moreover, excessive vegetative growth diverts a greater share of nutrients away from the fruits, resulting in reduced fruit yield and quality.
5. Improper soil fertilization practices reduce fertilizer use efficiency.
When applying fertilizer to the soil, it is essential to maintain appropriate application depth and keep a proper distance from the root zone. During fertilization, increase the application area to ensure even distribution, thoroughly incorporate the fertilizer into the soil, and combine fertilization with irrigation.
If fertilizer is applied too shallowly, it is easily leached away, leading to waste; if applied too deeply, it remains too far from the root zone to be effectively utilized by the plant, also reducing fertilizer efficiency.
If fertilizer is not thoroughly mixed with the soil, resulting in localized concentrations that are too high, root burn may occur, adversely affecting plant growth, reducing yields, and even causing plant death.