What causes autumn yellowing in citrus? Detailed explanation of solutions
As autumn arrives, some citrus plants develop yellowing, which is known as autumn yellowing. Autumn yellowing is a fairly common phenomenon and also one that gives fruit growers headaches. It is related to how well the fruit trees grow and affects both yield and quality, so what causes citrus autumn yellowing? Let's take a look.
1. Nutrient imbalance
Autumn is the fruit expansion and ripening period, and at this time a large amount of nutrients is needed. The same is true for the sprouting of autumn shoots, and root development is also at its peak. If the plant's nutrient supply is insufficient at this time, or because too many fruits are hanging on the tree, it can lead to nutrient imbalance. In particular, when trace elements are lacking, autumn yellowing can occur. Common nutrient problems are generally deficiencies of elements such as zinc, iron and magnesium.
2. Root damage
The root system is an important organ through which the plant obtains nutrients, and the growth and development of the planting cannot be separated from it. If the root system is damaged at this time, its absorption capacity declines, and since the plant needs a lot of nutrients, autumn yellowing is very likely to occur. The factors that damage the root system are mainly high temperature and drought, waterlogging that suffocates the roots, soil compaction, and root burn caused by high fertilizer concentration. These factors that cause root damage should be kept firmly in mind.
3. Pests and diseases
Damage from pests and diseases is also one of the causes of autumn yellowing. They harm the plant's leaves, twigs and root system, affect the plant's photosynthesis and respiration, hinder nutrient synthesis and nutrient absorption, and cause the plant to develop autumn yellowing. The main pests and diseases are root rot and nematode disease. The former causes the root system to rot, and in severe cases the planting dies; the latter parasitizes the root system in the later stage, causing the root system to be covered with knots and unable to absorb nutrients normally.
4. Soil pH imbalance
An imbalance in soil pH will reduce the solubility of trace elements such as phosphorus, magnesium and zinc, causing the plant to show deficiency symptoms and produce a phenomenon similar to nutrient imbalance; while excessive pH will increase the solubility of elements such as aluminum, manganese and copper, causing the plant to suffer toxicity and leading to yellowing.
5. Poor soil capacity to retain fertilizer and water
When the soil's aggregate structure is poor, water is easily lost through evaporation and fertility is easily lost. Its capacity to retain fertilizer and water declines, and its air permeability also becomes worse, affecting the normal respiration of the root system and hindering root growth. In addition, the massive loss of nutrient elements easily causes the plant to show deficiency symptoms and normal yellowing.
6. Solutions
For the autumn yellowing phenomena caused by the various nutrient problems above, the methods to solve them mainly revolve around improving the soil and nourishing the roots. First, reasonably increase the application of organic fertilizer, increase the organic matter in the soil, raise the content of trace elements, improve the soil structure, and enhance the soil's capacity to retain fertilizer and water. In addition, pH imbalance can also be adjusted through fertilizer.
The above are the causes of citrus autumn yellowing and the solutions. We hope this can help you. If you want to learn more about citrus cultivation, please stay tuned to us.