(1) Symptoms
a. The leaves growing at the top of the early shoots in early spring are smaller than normal. The new shoots are short, and the top leaves are crowded together in a cluster, forming a pathological condition, also known as lobular disease. In the early stages, irregular yellow or chlorotic areas appear between the veins. These isolated chlorotic parts gradually merge into a yellow elongate zone, from the midrib to the leaf margin, forming a continuous chlorotic edge at the leaf edge.
b. Most of the leaves have a wider green portion along the veins and around the yellow area, which is different from the manganese deficiency. The leaves at the top of the summer shoots are yellowish, and there are only a few green parts along the veins. Red or purple stains sometimes appear in these chlorotic areas, which later die and fall off, forming voids.
c. The zinc-deficient tree knot has small fruit and fruit shape. The fruit at the top of the big branch appears to be small and flat. Mature peaches are broken.
d. On a tree, leaf and fruit symptoms can only appear on one large branch or several large branches, while the rest of the tree appears to be healthy.
(2) Conditions of occurrence
a. The sandy orchard soil is thin and contains less zinc; the water permeability is good, the soluble zinc salt is easy to be lost; the irrigation is too much, and the soluble zinc salt is also easy to be lost, so the incidence is heavier.
b. Fertilizer application, especially excessive nitrogen fertilizer, requires an increase in the amount of zinc in fruit trees, so orchards that intercropped as vegetables tend to be severely affected. Due to the high pH of the saline-alkali soil, zinc is easily fixed, is not easily absorbed by the roots, and the incidence is also heavy.
c. Soil viscosity, shallow soil layer, root dysplasia, is also prone to zinc deficiency.
(3) Correction method
a. Add organic fertilizer. It can lower the soil pH, increase the solubility of zinc salt, and facilitate the absorption and utilization of fruit trees.
b. Supplement zinc. Spray 3% to 5% of zinc sulphate on the pre-emergence tree or spray 1% zinc sulphate solution at the beginning of germination. The effect is obvious in the year. Before germination or initial germination, apply 1% to 2% zinc sulphate solution on the diseased branches to promote the growth of new shoots. Studies have shown that spraying 0.2% zinc sulphate plus 0.3% urea or 300 mg gram of zinc naphthenate 3 weeks after flowering has a significant effect on reducing the disease. For 2 consecutive years, the recovery rate of diseased branches can reach 97%. Production increased by 16%-20%. Combined with spring and autumn base fertilizer, each plant is planted (about 15 years old) with 0.25-0.5 kg of zinc sulphate, which is effective in the second year after application and lasts for 3-5 years.
c. Improve the soil. For orchards with poor soil conditions such as saline-alkali land, clay land and sandy land, biological measures or engineering measures should be used to improve the soil, release the fixed zinc element, create favorable conditions for root development, and fundamentally solve the problem of zinc deficiency. .
Huaxian Agricultural Technology Promotion Center Lu Shuguang
a. The leaves growing at the top of the early shoots in early spring are smaller than normal. The new shoots are short, and the top leaves are crowded together in a cluster, forming a pathological condition, also known as lobular disease. In the early stages, irregular yellow or chlorotic areas appear between the veins. These isolated chlorotic parts gradually merge into a yellow elongate zone, from the midrib to the leaf margin, forming a continuous chlorotic edge at the leaf edge.
b. Most of the leaves have a wider green portion along the veins and around the yellow area, which is different from the manganese deficiency. The leaves at the top of the summer shoots are yellowish, and there are only a few green parts along the veins. Red or purple stains sometimes appear in these chlorotic areas, which later die and fall off, forming voids.
c. The zinc-deficient tree knot has small fruit and fruit shape. The fruit at the top of the big branch appears to be small and flat. Mature peaches are broken.
d. On a tree, leaf and fruit symptoms can only appear on one large branch or several large branches, while the rest of the tree appears to be healthy.
(2) Conditions of occurrence
a. The sandy orchard soil is thin and contains less zinc; the water permeability is good, the soluble zinc salt is easy to be lost; the irrigation is too much, and the soluble zinc salt is also easy to be lost, so the incidence is heavier.
b. Fertilizer application, especially excessive nitrogen fertilizer, requires an increase in the amount of zinc in fruit trees, so orchards that intercropped as vegetables tend to be severely affected. Due to the high pH of the saline-alkali soil, zinc is easily fixed, is not easily absorbed by the roots, and the incidence is also heavy.
c. Soil viscosity, shallow soil layer, root dysplasia, is also prone to zinc deficiency.
(3) Correction method
a. Add organic fertilizer. It can lower the soil pH, increase the solubility of zinc salt, and facilitate the absorption and utilization of fruit trees.
b. Supplement zinc. Spray 3% to 5% of zinc sulphate on the pre-emergence tree or spray 1% zinc sulphate solution at the beginning of germination. The effect is obvious in the year. Before germination or initial germination, apply 1% to 2% zinc sulphate solution on the diseased branches to promote the growth of new shoots. Studies have shown that spraying 0.2% zinc sulphate plus 0.3% urea or 300 mg gram of zinc naphthenate 3 weeks after flowering has a significant effect on reducing the disease. For 2 consecutive years, the recovery rate of diseased branches can reach 97%. Production increased by 16%-20%. Combined with spring and autumn base fertilizer, each plant is planted (about 15 years old) with 0.25-0.5 kg of zinc sulphate, which is effective in the second year after application and lasts for 3-5 years.
c. Improve the soil. For orchards with poor soil conditions such as saline-alkali land, clay land and sandy land, biological measures or engineering measures should be used to improve the soil, release the fixed zinc element, create favorable conditions for root development, and fundamentally solve the problem of zinc deficiency. .
Huaxian Agricultural Technology Promotion Center Lu Shuguang
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