From November to late spring, specifically February, pruning is an essential practice for ginkgo trees. Grafting seedlings are typically planted in a short-dry natural form without the need for extensive shaping. The primary goal of pruning is to remove dead, diseased, or crowded branches, as well as drooping and overlapping ones. Short and old branches should be cut back to encourage new growth and the formation of fruiting branches. This helps in developing a more productive and balanced canopy.
When planting grafted seedlings, the recommended spacing is 4 meters by 5 meters. For non-grafted seedlings, the spacing can range from 5x6 meters to 7x8 meters. To ensure proper pollination, it's advised to plant 1/15 to 1/20 male trees per female tree. In areas where intercropping with other crops is practiced, wide belts with 8-meter row spacing and 4–5-meter plant spacing are ideal. Trees are often planted along roadsides, village edges, irrigation channels, and riverbanks. In parks and industrial zones, ginkgo trees are used as ornamental plants, offering both beauty and economic value. A planting hole of 80 cm in size and 60 cm deep is recommended, filled with 50 kg of organic fertilizer (such as compost or manure), plus 0.5 kg of superphosphate.
In early spring, around March, large ginkgo trees (with over 50 kg of seeds) should receive 100 kg of well-rotted manure or human waste, 2 kg of urea, and 2 kg of superphosphate per tree. This fertilization supports the development of female flowers, flowering, and seed production. Seed sowing is commonly done with a spacing of 20–25 cm between rows and 8–10 cm between seeds, using about 60–70 kg of seeds per acre. Seedlings under 10 years old should be soaked in fresh water for 16 hours before planting, ensuring a 100% survival rate. Using cuttings and seedlings helps maintain the desirable traits of the female parent and allows for earlier fruiting.
Ginkgo grafting involves two main methods: large anvil grafting and seedling grafting. Seedlings grafted at 1–2 years old use scions from 1–3-year-old branches that match the rootstock in thickness. Techniques include cleft grafting, splice grafting, tongue grafting, and bark grafting. Small rootstocks can also use bud grafting, which can lead to fruiting 2–3 years earlier. For larger rootstocks over 5 years old, skin grafting or subcutaneous grafting is preferred, with the graft site located 1.5–2 meters up the trunk. Scions from 3–4-year-old short branches, around 20 cm long, can produce results within 2–3 years and help control canopy size. Stakes are often used to support upright growth.
In April, during the flowering period, ginkgo is dioecious, meaning there are separate male and female trees. Males are usually taller with narrower crowns and produce more pollen. Pollen should be collected when female flowers are fully open, and pollination should be done evenly to avoid overproduction, which can lead to alternate bearing. In some regions, male trees have been removed, causing a lack of pollen, so artificial pollination is necessary.
From May to June, another round of fertilizer is applied, using the same amounts as in early spring. Winter green manure is plowed in, and summer green manure such as mung beans, black beans, and kidney beans are sown. When canopy coverage is below 0.5, intercropping with peanuts, soybeans, broad beans, rapeseed, ginger, and daylilies is still possible.
During July and August, summer weeding is important. Manual weeding or chemical methods like glyphosate (265g per 50kg water, 40–50kg per mu) or trifluralin (50g per 15kg water, 50–60kg per mu) can be used to control weeds.
From late September to mid-October, it's the ideal time for seed collection. Popular varieties include Home Buddha Finger, Dongting Yellow, Golden Fruit Bergamot, Damei Nuclear, and Yuanguo Bergamot. Seeds should be harvested when the outer layer turns orange and begins to fall naturally. Harvesting too early leads to poor germination and low yield. After harvesting, seeds should be spread on mats or flat surfaces, covered with straw, and not watered or buried. The layer should not exceed 40 cm. Once the seed coat softens, it should be removed carefully, washed, and dried for 2–3 hours until the shell becomes shiny. Handling seeds requires gloves due to their corrosive nature. Leaves can also be collected and dried, but not in summer.
After harvest, apply 100 kg of fertilizer per tree, digging a ring-shaped trench around the tree and avoiding damage to major roots. Watering after fertilization improves nutrient absorption. In winter, green manure such as yellow peony or purple sorghum can be sown to enrich the soil.
Whitening Ingredient
Whitening supplements usually refer to nutritional supplements or food ingredients that can help improve uneven skin tone, reduce dark spots, and enhance skin brightness, thus achieving whitening effects. These components usually work by antioxidants, inhibiting melanin production, promoting melanin breakdown, or accelerating epidermal metabolism.
Here are some common whitening supplements:
1. Vitamin C (Ascorbic acid)
A powerful antioxidant, can inhibit tyrosinase activity, reduce melanin production, while promoting collagen synthesis, improve skin quality.
2. Glutathione
It is an endogenous antioxidant that can be used orally or topically to help reduce pigmentation and improve skin brightness.
3. Niacinamide (vitamin B3)
It can prevent the transfer of melanin to the skin surface, reduce the formation of stains, and has anti-inflammatory and moisturizing effects, improve skin barrier function.
4. Lipoic acid
A powerful antioxidant that can work with other antioxidants such as vitamins C and E to enhance the whitening effect.
5. Arbutin
Natural extract, can inhibit tyrosinase activity, reduce melanin production, commonly found in whitening skin care products.
6. Polyphenols (such as green tea extract, grape seed extract)
With antioxidant properties, can prevent skin damage caused by ultraviolet light, indirectly help whitening.
7. Collagen peptide
Although the direct whitening effect is limited, it can improve the elasticity and water retention of the skin, making the skin look fuller and brighter.
It is important to note that the effectiveness of whitening supplements varies from person to person, and usually requires a combination of good sun protection and reasonable lifestyle habits (such as adequate sleep, balanced diet, moderate exercise) to achieve the best results. When choosing a whitening supplement, it is recommended to consult a professional to ensure safety and suitability.
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