How to prevent and treat peach tree chlorosis? A full breakdown of practical methods

1. Causes  

1. Iron deficiency The main causes of iron deficiency in protected-cultivation peach trees:

① Planting density is high, some even reaching 1 m×0.8 m, the land nutrient area occupied by each tree is small, roots cross each other, and the iron ions released in the soil cannot meet the absorption needs of the root system.

② After the peach tree bears fruit, the load is heavy, organic nutrients are supplied preferentially to fruit growth, root growth is inhibited, the ability of the root system to secrete acidic substances is weakened, and the iron ions in the soil cannot be effectively absorbed by the root system.  

③ Affected by soil pH, iron ions in neutral and slightly alkaline soils are easily fixed by hydroxide ions, forming insoluble ferric hydroxide, which cannot be absorbed by the peach tree root system, resulting in iron deficiency symptoms, and these mainly occur on new leaves.  

2. Too-heavy pruning after fruit harvest Before fruit harvest, various organic and inorganic nutrients are mainly supplied to fruit growth, and root growth is inhibited. After fruit harvest, the root system urgently needs organic nutrients supplied by the leaves. If heavy renewal pruning is carried out at this time, the aboveground part loses a large number of nutrient-bearing branches and leaves, causing insufficient nutrient supply for underground root growth, causing fine roots to die due to excessive pruning, and the root system cannot absorb nutrients well, resulting in insufficient nutrient supply to the aboveground part.  

3. Too much chemical fertilizer, too little organic fertilizer Long-term heavy application of chemical fertilizers causes soil compaction, poor physical and chemical properties, barren soil, poor structure, low organic content, and reduced soil active bacteria, affecting the decomposition and release of soil nutrients. Heavy, sticky soil and poor permeability affect root growth. 

4. Root diseases Peach tree root diseases are another important cause of peach leaf yellowing. If a plant suffers from crown gall, violet root rot, root rot, and other diseases, root growth is affected, nutrient and water absorption by the root system is hindered, tree vigor declines, and in severe cases the plant dies.  

2. Prevention and control  

1. Prevention and control of iron deficiency ① Sparse planting: planting density of 2.5 m×1 m to 3 m×1 m, increasing the soil range for root absorption of nutrients and water, so that iron ions in the soil can meet root absorption and create a good growing environment for plant growth. ② Reasonable load: determine yield according to the peach tree condition, generally no more than 3000 kg per mu, then break down the per-mu yield to each tree. The formula for the fruit retention amount per tree is: fruit retention amount (number of fruits) ≈ per-tree yield (kg) / single fruit weight (kg). ③ Spray foliar fertilizer: spray the leaves with 0.1% ferrous sulfate plus 500 times rice vinegar essence solution. ④ Infusion treatment: when individual shoots on the plant are iron deficient, hang a bottle containing a mixed solution of 0.1% ferrous sulfate and 0.5% acetic acid on the tree, and insert the iron-deficient shoots directly into the bottle. The above mixed solution can also be put into an infusion bottle, hung upside down on a branch, a hole drilled in the trunk, and infused with a medical infusion set.  

2. Light pruning after fruit harvest After fruit harvest, prune the fruiting branches, mainly by thinning, removing back branches, upright branches, thin and weak branches, diseased and pest-damaged branches, and crossing branches, combined with artificial pinching, shoot twisting, branch bending, etc., retaining a certain number of nutrient branches to balance tree vigor.  

3. Reasonable fertilization; increase application of high-quality organic fertilizer, control application of chemical fertilizer For plots with heavy, sticky soil, apply high-quality organic fertilizer in autumn to improve soil permeability and improve soil physical and chemical properties. If the soil is relatively sticky and heavy, filling some river sand into the planting pit has a certain effect.  

4. Prevention and control of root diseases Check whether seedlings have diseases. Soak the roots for 1 minute with 1% copper sulfate solution or 2% lime water, or soak the roots for 5 minutes with K-84 (Aikangning), then plant. If crown gall-infected plants are found, cut off the root tumors with a sharp knife and disinfect with 100 times 1% copper sulfate solution.