Detailed Explanation of the Key Cultivation Techniques for Changyuan No. 1 Ponkan
Cultivation Key Points for Changyuan No. 1 Ponkan
1. Rootstock-Scion Combinations
Use sour orange, small-leaf trifoliate orange (Poncirus trifoliata), or Jiangxi red tangerine as rootstock. Sour orange rootstock gives high yields but begins bearing somewhat late; small-leaf trifoliate orange rootstock produces a dwarfed canopy, bears early, and has good yielding ability; Jiangxi red tangerine rootstock gives a moderate tree vigor, bears early, and has strong yielding ability.
2. Appropriate Close Planting
For trifoliate orange rootstock, plant 112-145 trees per mu (3 m x 2 m to 2.3 m x 2 m); for Jiangxi red tangerine rootstock, plant 112 trees per mu. After fruiting, as the canopy expands and branches cross, promptly carry out heading back and renewal pruning to maintain a good canopy.
3. Reasonable Fertilization
In the first two years after planting, the purpose of fertilizing young trees is to promote rapid canopy growth. Generally, fertilize 2-3 times for each flush according to its sprouting, growth, and turning green, with nitrogen fertilizer as the main type. After the trees begin bearing, apply fertilizer separately throughout the year as follows: First, fertilizer to promote flowering and strengthen flower buds. For trees of moderate vigor, apply decomposed manure 15 days before the flower buds turn white; use high-quality bran fertilizer or human and livestock urine fertilizer and compound fertilizer; for vigorous trees, apply only when flowers appear, applying more when there are many flowers and less when there are few, with the amount used accounting for about 25% of the total annual fertilizer application. Second, fertilizer to stabilize fruit after petal fall. Apply from after petal fall to the first physiological fruit drop period, spraying foliar fertilizers such as urea + monopotassium phosphate, magnesium sulfate, or Lvwang nitrogen and Lvwang potassium. Third, heavy application of autumn shoot fertilizer. Apply slow-release organic fertilizer 1 month before the autumn shoots emerge to strengthen the tree, and apply quick-acting fertilizer 10 days before the shoots emerge to promote them, with the application amount accounting for 35%-40% of the annual total. The organic fertilizer is peanut bran or chicken manure, and the quick-acting fertilizer is urea mixed with compound fertilizer. Fourth, fertilizer for fruit enlargement and flower bud differentiation, applied in mid-to-late October, mainly compound fertilizer or decomposed bran fertilizer and manure, with the application amount accounting for 15%-20% of the annual total. Fifth, fertilizer before harvest, applied before picking, mainly quick-acting nitrogen fertilizer, with the amount accounting for 10% of the annual total.
Pay attention to irrigation during the fruit enlargement period.
4. Canopy Training and Shoot Strengthening
Cultivate a canopy that bears early and yields well, along with strong fruiting mother branches. Starting from the first year after planting, adopt measures such as branch bending, shaping, bud removal and shoot release, and heading back to promote shoots, so as to form as quickly as possible a wave-like round-headed canopy that bears early and has strong yielding ability. For young trees, release shoots 3-4 times a year, requiring a two-year-old tree to have more than 100 effective autumn shoots. For fruiting trees, promptly remove early-declining shoots. 10-15 days before releasing autumn shoots, appropriately head back dense and weak branches in the middle and upper canopy, branches that dropped flowers and fruit, and excessively vigorous branches, to cultivate strong fruiting mother branches. For young and middle-aged trees, attention should also be paid to controlling winter shoots.
5. Fruit Retention and Fruit Thinning
(1) Fruit retention. During the flower bud stage, thin out strong vegetative spring shoots, promptly remove summer shoots, reduce physiological fruit drop, and spray growth regulators on the leaves. During the flower bud stage, spray 0.1% boric acid + 0.3% monopotassium phosphate + Lvwang nitrogen and potassium. Do a good job in drought prevention, waterlogging prevention, sunscald prevention, and pest and disease control to achieve fruit retention.
(2) Fruit thinning. To produce large fruit of high quality that meets specifications, in mid-to-late June first thin out diseased and insect-damaged fruit, deformed fruit, and small fruit inside the canopy. If the fruit load is especially heavy, part of the single terminal fruit can be thinned from the middle and upper canopy where autumn shoots are likely to emerge.
6. Pest and Disease Control
Changyuan No. 1 Ponkan is prone to many pests and diseases, so timely control is needed to protect leaves, protect fruit, ensure high and stable yields, and ensure high quality.
Use sour orange, small-leaf trifoliate orange (Poncirus trifoliata), or Jiangxi red tangerine as rootstock. Sour orange rootstock gives high yields but begins bearing somewhat late; small-leaf trifoliate orange rootstock produces a dwarfed canopy, bears early, and has good yielding ability; Jiangxi red tangerine rootstock gives a moderate tree vigor, bears early, and has strong yielding ability.
2. Appropriate Close Planting
For trifoliate orange rootstock, plant 112-145 trees per mu (3 m x 2 m to 2.3 m x 2 m); for Jiangxi red tangerine rootstock, plant 112 trees per mu. After fruiting, as the canopy expands and branches cross, promptly carry out heading back and renewal pruning to maintain a good canopy.
3. Reasonable Fertilization
In the first two years after planting, the purpose of fertilizing young trees is to promote rapid canopy growth. Generally, fertilize 2-3 times for each flush according to its sprouting, growth, and turning green, with nitrogen fertilizer as the main type. After the trees begin bearing, apply fertilizer separately throughout the year as follows: First, fertilizer to promote flowering and strengthen flower buds. For trees of moderate vigor, apply decomposed manure 15 days before the flower buds turn white; use high-quality bran fertilizer or human and livestock urine fertilizer and compound fertilizer; for vigorous trees, apply only when flowers appear, applying more when there are many flowers and less when there are few, with the amount used accounting for about 25% of the total annual fertilizer application. Second, fertilizer to stabilize fruit after petal fall. Apply from after petal fall to the first physiological fruit drop period, spraying foliar fertilizers such as urea + monopotassium phosphate, magnesium sulfate, or Lvwang nitrogen and Lvwang potassium. Third, heavy application of autumn shoot fertilizer. Apply slow-release organic fertilizer 1 month before the autumn shoots emerge to strengthen the tree, and apply quick-acting fertilizer 10 days before the shoots emerge to promote them, with the application amount accounting for 35%-40% of the annual total. The organic fertilizer is peanut bran or chicken manure, and the quick-acting fertilizer is urea mixed with compound fertilizer. Fourth, fertilizer for fruit enlargement and flower bud differentiation, applied in mid-to-late October, mainly compound fertilizer or decomposed bran fertilizer and manure, with the application amount accounting for 15%-20% of the annual total. Fifth, fertilizer before harvest, applied before picking, mainly quick-acting nitrogen fertilizer, with the amount accounting for 10% of the annual total.
Pay attention to irrigation during the fruit enlargement period.
4. Canopy Training and Shoot Strengthening
Cultivate a canopy that bears early and yields well, along with strong fruiting mother branches. Starting from the first year after planting, adopt measures such as branch bending, shaping, bud removal and shoot release, and heading back to promote shoots, so as to form as quickly as possible a wave-like round-headed canopy that bears early and has strong yielding ability. For young trees, release shoots 3-4 times a year, requiring a two-year-old tree to have more than 100 effective autumn shoots. For fruiting trees, promptly remove early-declining shoots. 10-15 days before releasing autumn shoots, appropriately head back dense and weak branches in the middle and upper canopy, branches that dropped flowers and fruit, and excessively vigorous branches, to cultivate strong fruiting mother branches. For young and middle-aged trees, attention should also be paid to controlling winter shoots.
5. Fruit Retention and Fruit Thinning
(1) Fruit retention. During the flower bud stage, thin out strong vegetative spring shoots, promptly remove summer shoots, reduce physiological fruit drop, and spray growth regulators on the leaves. During the flower bud stage, spray 0.1% boric acid + 0.3% monopotassium phosphate + Lvwang nitrogen and potassium. Do a good job in drought prevention, waterlogging prevention, sunscald prevention, and pest and disease control to achieve fruit retention.
(2) Fruit thinning. To produce large fruit of high quality that meets specifications, in mid-to-late June first thin out diseased and insect-damaged fruit, deformed fruit, and small fruit inside the canopy. If the fruit load is especially heavy, part of the single terminal fruit can be thinned from the middle and upper canopy where autumn shoots are likely to emerge.
6. Pest and Disease Control
Changyuan No. 1 Ponkan is prone to many pests and diseases, so timely control is needed to protect leaves, protect fruit, ensure high and stable yields, and ensure high quality.