When to propagate kiwi
The editor introduces to you when to propagate kiwi and the related knowledge of kiwi planting techniques and management. Next, the editor of this site will introduce to everyone.
Kiwi has a soft texture, sweet and sour taste, and is rich in nutrients. It contains not only organic substances such as kiwi alkaloid, proteinase, and pectin, but also trace elements such as calcium, potassium, zinc, and 17 types of amino acids required by the human body. It also contains vitamin C, tartaric acid, malic acid, and other minerals, and is known as the "king of fruits." In recent years, with the improvement of people's living standards, the demand for kiwi has been increasing, and the price is high. Liupanshui City is located in the abdominal mountains of the Yunnan-Guizhou Plateau, which is the watershed of the Yangtze River and the Pearl River. The climate is warm, the air is fresh, and the sunshine is abundant, making it the only city in China named after the climate. The temperature difference between day and night is significant, with low latitude and high altitude, creating a climate environment suitable for kiwi growth, and is known as the "hometown of wild kiwi in China."
1 Key points of kiwi cultivation techniques
1.1 Site selection
When selecting a site, it is necessary to fully consider factors such as sunlight, water, and soil organic matter. Kiwi has high requirements for the growth environment and is suitable for planting in warm and humid climates, mainly in subtropical and temperate humid and semi-humid climates, mainly distributed between 18° and 34° north latitude, with an average annual temperature of 11-17°C and a frost-free period of 160-270 days. Liupanshui City is located in the Wumeng Mountains in the western part of Guizhou Province, with complex terrain mainly consisting of mountains, hills, basins, plateaus, and tablelands. The terrain undulates significantly and belongs to the subtropical monsoon climate. Influenced by the terrain, the summer is cool and the winter is warm, with an average annual temperature of 13-14°C and a frost-free period of 200-300 days. The warm and humid environment has created favorable conditions for kiwi growth. Kiwi requires more water and belongs to a fruit tree with weak physiological drought resistance and weak humidity resistance. It has high requirements for planting soil and air humidity and is suitable for cultivation in areas with abundant rainfall and high air humidity. China's kiwi is mainly planted in environments with annual precipitation of 800-2,200 mm and air humidity of 74.3%-85%. Liupanshui City has an annual precipitation of 1,200-1,500 mm, with high altitude and frequent fog in mountainous areas, creating a humid environment conducive to kiwi growth. Kiwi loves sunshine but is sensitive to sunlight radiation, prefers diffused light, and dislikes direct strong sunlight. The natural light intensity is generally controlled at around 42%-45%. It is suitable for planting in sunny areas with 1,300-2,600 hours of sunlight, deep and well-drained, loamy soil with high organic matter content and slightly acidic pH. If the soil is strongly acidic or alkaline, it needs to be treated. It should be planted in an environment with a pH of 5.5-6.5. Kiwi requires a large amount of nitrogen, phosphorus, potassium, manganese, and other mineral elements during growth. Before planting, the soil components need to be measured, and a certain amount of green manure should be applied. The altitude of kiwi planting in Liupanshui City should be controlled between 1,000 and 1,600 meters. In addition, kiwi has weak wind resistance, which can easily cause young branches to break, leaves to shatter, fruits to be bruised or fall, affecting the yield and quality of kiwi. Therefore, it is best to avoid areas with strong winds and high mountains and plant on the leeward slopes.
1.2 Seed selection
Kiwi seed selection is directly related to the yield and quality of kiwi. When planting, try to choose local kiwi varieties, which have good adaptability and resistance and can better adapt to local climatic conditions, reducing the probability of diseases and pests. Liupanshui City's red-hearted kiwi is a large fruit variety with neat fruit shape, beautiful appearance, and bright green flesh inside when ripe. The cross-section of the fruit is red with red stripes radiating from the core, which is aesthetically pleasing. It obtained the national geographical indication agricultural product in 2012, and in 2020, the kiwi base in Shuicheng District of Liupanshui City was selected as the "National Torch Industry Base" and "China Characteristic Agricultural Product Advantage Zone." When selecting seeds, choose a main planting variety based on local conditions and pair it with another variety for planting.
1.3 Breeding
Kiwi seeds are propagated through methods such as grafting, cutting, or layering. Every year during the kiwi maturity season, select kiwi fruits with correct shape, uniform size, and bright color. After the flesh matures and softens, mash the flesh, wrap it in gauze, squeeze the flesh into the gauze to separate the seeds from the flesh, then wash the seeds with clean water repeatedly until the flesh is clean. After washing, dry the seeds. Soak the seeds in 40-50°C warm water for 2-3 hours, then in cold water for 12 hours. When the soil temperature reaches 0-5°C, bury the seeds in moist river sand for 50-60 days. In the second year, when spring warms up, choose loamy soil for land preparation and fertilization, and broadcast the kiwi seeds in the seedbeds. Before sowing, prepare the seedbeds, apply decomposed organic fertilizer to the soil, control the seedbed width to 1 meter, finely crush and slightly press the soil, then water it. After sowing, cover the seed surface with a layer of sand, with a sand thickness of 1-2 cm. A greenhouse 2-5 meters high can be built on the seedbed. The greenhouse frame is made of bamboo or steel, fixed with double-stringed rafters on the roof, covered with plastic film to store heat, keep warm, and maintain humidity, and稻草 curtains are laid on the roof for timely ventilation. When the seedlings have 2-3 true leaves, start thinning, removing weak, diseased, and small seedlings, with a thinning distance of 2-3 cm. When the seedlings have 5 true leaves, start transplanting and setting.
1.4 Setting
Before setting, dig ditches according to the actual conditions of the orchard. For mountainous ditches, follow the contour lines to build terraces, with the ditch line facing inward and the width of the terraced fields being 3-3.5 meters. For flat land, follow the row spacing to dig ditches, generally 0.8-1 meter wide and 0.6-0.8 meter deep. When digging ditches, separate the surface soil and bottom soil and pile them up separately. Fill the bottom of the ditch with 2-3 layers of green grass, with an amount of 37,500 kg/hm2. If the planting area is red soil, add lime to improve the soil pH. Cover the green grass with surface soil, then apply organic fertilizer on the surface soil, with a fertilizer amount of 7,500 kg/hm2, mix the fertilizer and surrounding soil thoroughly, then cover with surface soil. Kiwi is a woody vine plant, and the planting density should not be too high. The row spacing is set to 30-50 cm, and the plant spacing is 10-15 cm. When planting, choose strong seedlings, dig a hole of 0.3-0.4 m2 in the orchard, place the seedlings in the hole, fully stretch the roots, bury the roots in the middle position of the soil, lift the seedlings twice to fully stretch the roots, then fill and compact the soil, and water thoroughly on the surface. Kiwi is a large deciduous woody vine plant with separate male and female flowers. When planting, it needs cross-pollination to bloom and bear fruit. When planting, a certain number of male plants need to be set up, with the male plant flowering 3-7 days earlier than the main cultivated variety, choosing varieties with a large amount of pollen and long flowering period. The male to female plant ratio is 5:1 or 6:1. The planting density of kiwi trees needs to be determined in combination with the cultivation trellis, with common trellises being T-type, flat-top trellis, and hedge trellis. The hedge trellis is 2.5-3 meters long, with a diameter of 0.12-0.15 cm and a ground net height of 1.8-2 meters, with a trellis density of 2 m×4 m. The T-type trellis is directly set with horizontal beams on the upright支柱, forming a T-shaped trellis. This trellis is 2.8-3 meters long, the beam is 1.2-1.5 meters long, and there are 3 anti-rust wires on the beam. The trellis is buried 0.8 meters deep in the ground, with a ground net height of 2 meters and a planting density of 3 m×4 m. The flat-top trellis is set up at every 5-6 meters, with a trellis height of 1.8-2 meters and a buried depth of 0.8 meters. The trellis is arranged in a square pattern, with the pillars around the棚架 connected with steel, and the pillars connected with wire to form a shed, with a planting density of 3 m×5 m.
1.5 Grafting seedlings
Grafting is a key point in kiwi cultivation, directly affecting the yield and quality of kiwi. Choose the single-bud cutting method, select a sturdy scion with a small pith, cut off a 3-4 cm long branch segment with a bud, cut off the surface smoothly, and cut a 50°斜削 face on the reverse side of the cutting surface. Cut the scion 10-15 cm from the ground, with a cutting length greater than 3 cm and a depth of 2-3 cm, then cut 2/3 of the scion bark, insert the scion, and wrap it with plastic film until the scion bud grows, then loosen the plastic film. After the scion is successfully grafted, cut the scion at the cutting position.
1.6 Inter-cropping management
Kiwi is sensitive to water and fertilizer. Once nutrients are lacking, kiwi will show symptoms such as yellow leaves, small leaves, and stopped growth. During planting, it is necessary to top-dress kiwi in a timely manner to meet the nutrient needs of the fruit tree. When the seedlings grow to 50 cm, top-dress once with 60-75 kg/hm2 urea and 135-150 kg/hm2 superphosphate. Seedling fertilization should follow the principle of small and frequent applications to avoid burning the roots. Before the seedlings germinate, top-dress once with 90-150 kg/hm2 urea. During the flowering period and early fruiting period, top-dress once with 0.3% potassium dihydrogen phosphate and 0.2% urea solution. During the fruit expansion period, the demand for fertilizer is high, and 60-75 kg/hm2 compound fertilizer and 90-150 kg/hm2 organic fertilizer should be applied.
In the later stage of fruit growth, apply potassium fertilizer and phosphorus fertilizer, with potassium fertilizer at 90-120 kg/hm2 and phosphorus fertilizer at 75-105 kg/hm2. Kiwi is a broad-leaved fruit tree, which likes water but fears waterlogging, with shallow root distribution. It needs to maintain air and soil moisture during growth. After each fertilization, water promptly. In summer, with strong transpiration, more water is needed. In autumn, when rainfall is concentrated, drainage ditches should be opened. In the vigorous growth period of kiwi in summer, it is necessary to intercrop and remove weeds in a timely manner, loosen the soil, and maintain the moisture and drought resistance of kiwi trees. In winter, planters need to cut off the僵 fruit, diseased branches, and insect branches in the orchard and burn them together to reduce the probability of disease and pest infection the following year. Then, plow the empty land in the orchard to kill overwintering pests.
1.7 Shaping and pruning
When the fruit tree grows tall, it is necessary to prune the tree shape properly to promote tree growth. According to the kiwi trellis, choose different shaping methods. Hedge-type trees mainly reduce the main vines and prune them into a fan-shaped tree. T-type trellises mainly use light pruning to promote flowering and fruiting. After planting, the main trunk, main vines, and long branches growing from the rootstock, except for the reserved preparation branches, should be pruned. In the summer, when the young trees grow vigorously, it is necessary to control their growth to avoid growing too many new shoots, which can affect the growth of the main trunk. In the flowering period, it is necessary to uniformly remove 2-3 leaves on the fruiting branches. For mature kiwi trees, the tendrils should be pruned 3-4 leaves in advance and pruned at the 15th leaf of the spring shoot. Pruning mainly removes weak branches, crossed branches, diseased branches, dense branches, long branches, insect branches, and useless suckers to promote the growth of strong branches and main branches.
2 Disease and pest control of kiwi
Disease and pest control is a key point in kiwi cultivation management, directly affecting the quality of kiwi. The main diseases and pests of kiwi include gray mold, blossom blight, leaf spot, golden龟甲, and scale insects. According to different diseases and pests, choose different control methods, common methods including physical control, biological control, and chemical control. Golden龟甲 eats kiwi tender shoots and can be controlled using frequency vibration insect killer lights, taking advantage of the phototaxis of pests to attract and kill them. Scale insects are one of the main pests in orchards, with small bodies, fast reproduction, and difficult control. Biological control can be used, releasing predators such as Australian ladybirds, aphid lions, and chalcid wasps in the orchard to achieve pest control. Gray mold and blossom blight can be controlled using chemical measures, choosing low-toxic and high-efficiency chemical agents. 3-5 degrees of lime sulfur solution can prevent blossom blight, and 800 times liquid zineb can prevent gray mold. These chemical agents are fast-acting and can eliminate diseases and pests.
Kiwi has very high nutritional value and is a treasure among fruits. During planting, it is necessary to combine local natural environment and climate conditions, choose the right kiwi varieties, strengthen orchard management, water and fertilize in a timely manner to meet the nutrient needs of the fruit trees, promote tree growth, reduce the probability of diseases and pests, improve the quality of kiwi, and achieve agricultural efficiency and increased income for farmers.
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