Management method for seedling culture and open-air cultivation of prinsepia utilis

Abstract

The invention discloses a prinsepia utilis seedling culture and open-air cultivation management method, and belongs to the technical field of ornamental plant seedling breeding and cultivation management. After dozens of years of practice and summarization, the inventor practices a set of complete technology and management method suitable for open-air cultivation of the prinsepia utilis in China. According to the method, through a series of management and cultivation work such as pond cleaning and airing, germination accelerating, seedling raising, field planting, fertilization and pest control, the maximum diameter of the leaves of the prinsepia utilis can reach 2.3 m, the average diameter of the leaves of the prinsepia utilis can reach 1.75-1.8 m, the leaves of the prinsepia utilis can bear the weight of 80 kg or below, meanwhile, more seeds with breeding capacity can be harvested, and the overall conservation level of the prinsepia utilis can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of ornamental plant seedling propagation and cultivation management, and in particular to a Victoria amazonica seedling raising and open-air cultivation management method. Background Art

[0002] Victoria amazonica (Poepp.) Klotzsch is the common name for plants of the genus Victoria in the family Nymphaeaceae. Victoria amazonica is native to tropical America, the Amazon River Basin, the Paraná River Basin, Argentina, Bolivia and other places. It likes high temperature, high humidity and a sunny growth environment. The optimum temperature for growth is 25-35℃. It grows slowly when it is below 20℃. Victoria amazonica is a perennial plant in its native place. Victoria amazonica has huge leaves that float on the water surface, with a diameter of 1-3 meters. The edges of the leaves are rolled up, and the entire leaf floats on the water surface, which is very spectacular. Victoria amazonica has the most beautiful, huge and unique round leaves in the world, and the flowers are beautiful, fragrant and delicate. The flowers are white when they first bloom and can gradually turn into deep red as the flowering process continues. The leaf viewing period can reach 150 days and the flower viewing period can reach 90 days. Using it in waterscape gardening can form a unique waterscape.

[0003] The flower of Victoria amazonica is very large, solitary, 25-40 cm in diameter, with 4 green-brown sepals, ovate and triangular, all covered with thorns on the outside; there are many petals, obovate, 10-22 cm long, many stamens, flat filaments, 8-10 mm long; the lower part of the ovary is covered with dense and thick thorns. Victoria amazonica blooms in summer or autumn, and opens above the water in the evening. It is very fragrant. The first day is white, with the fragrance of white orchid, and gradually closes on the second day. It opens again in the evening, and the petals turn light red to dark red. On the third day, it closes and withers and sinks into the water, and the seeds mature in the water. Victoria amazonica flowers have the characteristic of pistil maturing first. When they just open, the pistil is already mature, while the stamens are not yet mature and shed. Victoria amazonica fruits around September, the berries are spherical, the seeds are black, and when the fruit is ripe, it contains 300-500 seeds, and as many as 700.

[0004] Although Victoria amazonica is a perennial plant, it needs to be re-sown, raised and transplanted every year in my country. There is no complete set of planting technology. The average leaf diameter of Victoria amazonica in China is 1.4-1.5m. In addition, there are the following problems: 1. The seeds germinate unevenly during seedling raising, and the seedlings are of different sizes; 2. A Victoria amazonica plant only blooms one flower at a time, and another one blooms after the flower withers. The flowering is rare and the flowering period is different. At the same time, there are few pollinating insects. If the cultivation technology is not in place, the plant will grow poorly, the number of flowers is small, and the fruit setting rate is not high, resulting in many fruits being empty after the fruits mature, resulting in few Victoria amazonica seeds and insufficient seedling supply. 3. During planting, the roots and leaves are easily damaged, and the growth recovery period is long. 4. The plant ages quickly. At the end of October, the roots and stems of Victoria amazonica rot and the whole plant will float. How to extend the life of the plant?

[0005] In addition, seedling raising and open-air cultivation management involve many aspects, such as germination of Victoria regia seeds, flowering and fruiting, etc., all of which require exploration. After decades of practice and summary, the inventor has summarized a complete set of technologies and management methods suitable for open-air cultivation of Victoria regia in China.

[0006] After searching, it is found that there is no complete set of methods suitable for the open-air cultivation and management of Victoria amazonica in the prior art. Summary of the invention

[0007] Based on the above technical problems, the present invention intends to provide a method for raising seedlings and open-air cultivation of Victoria regia to solve the problems in open-air cultivation management in the prior art, so that the landscape effect is formed quickly, the number of flowers is large in the later stage, the fruit setting rate is high, a large number of seeds with breeding capacity can be obtained, the plant ages slowly, and the viewing period of Victoria regia is extended.

[0008] A method for raising Victoria amazonica seedlings and cultivating them outdoors comprises the following steps:

[0009] S1 Preparation of planting pond: When the temperature reaches 25℃, clean and dry the pond, and remove all aquatic plants, fish and golden apple snails in the pond; after cleaning, fully expose it to the sun for 5-7 days, and then disinfect and sterilize it;

[0010] S2 Planting baskets (pits) and their settings: Planting baskets (pits) are set up in places with deep water levels. The diameter of the planting baskets (pits) is 1.5-2m, and the height is greater than 70cm. The distance between the two baskets is at least 5-6m, and the top of the planting baskets (pits) is 1-1.5m from the water surface;

[0011] S3 Base fertilizer preparation: Fertile pond mud is placed at the bottom of each planting basket (pit), and then compound fertilizer and decomposed organic fertilizer are added; the organic fertilizer includes chicken manure, cow manure or oil residue;

[0012] S4 seed germination: Use black plastic bags to soak in shallow water and expose to strong light for germination. When the temperature reaches above 25℃, find a sunny location in the pond, put the seeds into the black plastic bag, immerse it in clean water and fix it at a depth of 10-15cm. Leave it for 10-15 days until the seeds germinate 1-2cm.

[0013] S5 Seedling cultivation: Soak the germinated seeds in a bucket with a water depth of 10-15cm, and cultivate the seedlings in a sunny environment. When the primary seedlings grow 2-3 leaves and 2-4 roots, move them into a flower pot with a diameter of 10-15cm; after planting, put them in water so that the leaves float on the water surface;

[0014] S6 Planting: When the leaf diameter reaches 15-30cm, it can be planted out of the nursery. The small pot for raising seedlings should be removed. The planting depth should not be too deep. It is better to bury it to the height of the soil ball in the small flower pot when raising seedlings. Do not bury the stem tip growth point (heart leaf bud) of the Victoria amazonica in the soil. Topdressing should be started 15 days after the seedlings are planted and survived. Fertilizer balls should be used for topdressing.

[0015] S7 Daily management, pruning of branches and leaves, and control of diseases and pests: Prune branches and leaves in time after entering the growth period. When pruning, cut off old leaves, yellow leaves, and appropriately cut off newly grown young leaves, leaving the growing leaves, and maintain 8-10 leaves per plant; and promptly remove snails and control diseases and pests.

[0016] Furthermore, the S4 seed germination method can be replaced by a constant temperature box germination method: the seeds are placed in a culture dish, the water surface covers the seeds, the culture dish is placed in a 28°C constant temperature box, and the water is changed once a day.

[0017] Furthermore, the mass ratio of the compound fertilizer in S3 to the decomposed organic fertilizer (chicken manure, cow manure or oil residue) is 1:5-1:6.

[0018] Furthermore, in the step S6, the fertilizer balls are made by mixing soil with good viscosity, compound fertilizer and urea in a ratio of 1:2:2 and kneading them into fertilizer balls with a diameter of 5-8 cm.

[0019] Furthermore, in the step S6, during topdressing, fertilizer balls are inserted into the soil 10-30 cm deep at a distance of 50-60 cm from the plants from different directions, and topdressing is performed once every 7-10 days. During the seedling stage, each plant is topdressed with one fertilizer ball divided into four portions. As the Victoria amazonica grows, the number of fertilizer balls can be increased to 2-4 per time per plant.

[0020] Furthermore, when fixing the plastic bag in the step S4, the bag mouth should not be tied too tightly, so that the water in the pool can be exchanged with the water in the plastic bag, thereby eliminating the work of changing the water every day.

[0021] Furthermore, in the S5, as the Victoria amazonica grows, the water level is adjusted to maintain at 50 cm, and the water is changed every 3-5 days depending on the water quality; the potting soil uses fertile pond soil, and the planting depth is preferably such that the seed shell is higher than the soil surface, and the roots must not be damaged during planting; topdressing begins 15 days after planting, and is applied once every half a month, each time using 3-5 grains of compound fertilizer pressed into the soil 5 cm away from the roots of the plant.

[0022] Furthermore, from the end of September to the beginning of October each year, adding soil to the roots of the Victoria amazonica to prevent the plants from floating and dying can effectively extend the survival period of the Victoria amazonica by 180 days.

[0023] Furthermore, the pest control in S7 mainly adopts the method of manually removing snails or placing larger plant leaves (such as palm leaves) on the edge of the pond to lure snails at night. When the number of snails is large, sand or soil is mixed with snail-killing amine ethanolamine salt and spread on the shallow water edge of the pond in the evening; the armyworm can be sprayed with 800 times diluted 90% trichlorfon original medicine, and aphids can be sprayed with 1000 times diluted 50% aphid pine emulsifiable concentrate; when brown spot disease and leaf rot of Victoria amazonica appear, spray methyl thiophanate or carbendazim for prevention and control.

[0024] Furthermore, when the S6 is transplanted, when the seedlings with a leaf diameter of more than 50 cm are transported over long distances, the leaves of the Victoria amazonica seedlings should be protected with newspapers, molds, etc., and a large plastic sheet should be placed on the bottom and around the transport vehicle to prevent water from leaking. Then, half a truck of sawdust is put in with water to allow all the sawdust to fully absorb water. The sawdust will generate heat after absorbing water, and the Victoria amazonica can be transplanted in it after the sawdust has cooled down.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention performs a series of management and maintenance work such as pond cleaning and sun drying, germination, seedling raising, field planting, fertilization and pest control. Now the maximum diameter of the leaves of Victoria amazonica can reach 2.3 meters, the average diameter can reach 1.75-1.8 meters, and it can bear a weight of less than 80 kilograms. At the same time, more seeds with breeding ability can be harvested, and the conservation level of Victoria amazonica is effectively improved. In addition, the landscape effect is formed quickly, the amount of flowers in the later period is large, the fruiting rate is high, a large number of seeds can be obtained, the plant ages slowly, the stamina is sufficient, and the viewing period is extended.

[0027] 2. The present invention uses a black plastic bag for shallow water immersion and strong light exposure for germination. The black bag absorbs heat and is immersed in shallow water. The bag mouth does not need to be tied tightly, so that the water in the bag and the water outside the bag can be freely exchanged. There is no need to change the water frequently, there is no need to pick out the hilum on the seed coat, and no other devices are required. It is convenient and fast. At the same time, the buds obtained by this method are uniform, which is convenient for seedling cultivation and plant flowering and fruiting.

[0028] 3. The present invention cultivates soil at the roots of Victoria amazonica from the end of September to the beginning of October each year to prevent the plants from floating and dying, which can effectively extend the survival period of Victoria amazonica by 180 days. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a picture of Victoria amazonica leaves obtained by the method of the present invention,

[0030] Figure 2 The load-bearing diagram of Victoria amazonica leaves obtained by the method of the present invention;

[0031] Figure 3 This is a comparison of the maximum diameter of Victoria amazonica leaves obtained by different methods;

[0032] Figure 4 This is a comparison chart of the growth trend of Victoria amazonica leaves obtained by different methods;

[0033] Figure 5 This is a comparison of Victoria amazonica seeds obtained by different methods; Figure 5 A is the picture of Victoria amazonica fruiting in 2023. Figure 5 B is the picture of Victoria amazonica fruiting in 2018;

[0034] Figure 6 This is a comparison of the Victoria amazonica landscape after the pond was cleared. Figure 6 A is the landscape of the Victoria regia before the pond is cleaned, and 6B is the landscape of the Victoria regia after the pond is cleaned Figure 7 Figure 2 shows different germination methods, among which Figure 7 A is a constant temperature box for germination; Figure 7 B is a black plastic bag of the present invention that is immersed in shallow water and exposed to strong light for germination. Figure 7 C is the seeds in the mesh bag exposed to shallow water for germination;

[0035] Figure 8 Create graphs for different fertilizers, where Figure 8 A is a shade net wrapped with compound fertilizer and farmyard manure. Figure 8 B is a fertilizer ball made by the method of the present invention, Figure 8 C is organic fertilizer wrapped in newspaper;

[0036] Fig. 9 This is a comparison of the stem and root of Victoria amazonica. Fig. 9 A is a picture of the rotting rhizome of Victoria amazonica. Fig. 9 B is the picture of the new root growth of Victoria amazonica. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0038] Example 1 A method for raising Victoria amazonica seedlings and cultivating them outdoors

[0039] A method for raising Victoria amazonica seedlings and cultivating them outdoors comprises the following steps:

[0040] S1 Preparation of planting pond: When the temperature reaches 25℃, clean and dry the pond, and remove all aquatic plants, fish and golden apple snails in the pond; after cleaning, fully expose it to the sun for 5-7 days, and then disinfect and sterilize it;

[0041] S2 Planting baskets (pits) and their settings: Planting baskets (pits) should be set up in places with deep water levels. The diameter of the planting baskets (pits) should be 1.5-2m, and the height should be greater than 70cm. The distance between the two baskets should be at least 5-6m, and the top of the planting baskets (pits) should be 1-1.5m above the water surface.

[0042] S3 Base fertilizer preparation: put fertile pond mud at the bottom of each planting pit (basket), then add compound fertilizer and decomposed organic fertilizer;

[0043] S4 seed germination: Use black plastic bags to soak in shallow water and expose to strong light for germination. When the temperature reaches above 25℃, find a sunny location in the pond, put the seeds into the black plastic bag, immerse them in clean water and fix them at a depth of 10-15cm. Leave them for 10-15 days. The seeds will germinate evenly and the buds will be 1-2cm long.

[0044] S5 Seedling cultivation: Soak the germinated seeds in a bucket with a water depth of 10-15cm, and cultivate the seedlings in a sunny environment. When the primary seedlings grow 2-3 leaves and 2-4 roots, move them into a flower pot with a diameter of 10-15cm; after planting, put them in water so that the leaves float on the water surface;

[0045] S6 Planting: When the temperature reaches above 20℃ and the leaf diameter reaches 15-30cm, it can be transplanted out of the nursery. At this time, the Victoria amazonica has more roots, and the soil ball is not easy to loosen when it is removed from the pot, and the transplanting survival rate is higher; the planting depth should be 1-1.5m, not too deep, and it is better to bury it to the height of the original soil ball. The deeper part of the pool should be surrounded by stones or bamboo to form a planting pit; do not bury the growth point of the stem tip of the Victoria amazonica in the soil; start topdressing 15 days after the seedlings are planted, and use fertilizer balls for topdressing; planting too close to the water surface will affect the growth of the Victoria amazonica's leaves and flower buds in the later stage.

[0046] S7 Daily management, pruning of branches and leaves, and pest and disease control: After entering the growth period, the branches and leaves should be pruned in time. When pruning, old leaves and yellow leaves should be cut off, and newly grown young leaves should be cut off appropriately, leaving the growing leaves, and each plant should maintain 8-10 leaves; snails should be removed in time, as well as pest and disease control. Prune branches in time during the growth period from June to July. Too many leaves will lead to deformed leaves, affecting the normal growth, flowering and fruiting of Victoria amazonica, as well as its ornamental value; clean up yellow leaves and branches every 10 days; Victoria amazonica is native to a warm climate all year round, and requires a high and stable temperature for growth and development. It is very sensitive to temperature, 25-30℃.

[0047] Furthermore, the S4 seed germination method can be replaced by a constant temperature box germination: use a sharp knife to pick off the hilum on the seed coat, place the seeds in a culture dish, submerge the seeds in water, place the culture dish in a 28°C constant temperature box, and change the water once a day.

[0048] Furthermore, the compound fertilizer and the decomposed organic fertilizer (chicken manure, cow manure or oil residue) in S3 are in a ratio of 1:5-1:6.

[0049] Furthermore, the fertilizer ball is made by mixing soil with good viscosity, compound fertilizer and urea in a ratio of 1:2:2 and kneading them into fertilizer balls with a diameter of 5-8cm.

[0050] Furthermore, in the step S6, the fertilizer is inserted into the soil 10-30 cm from different directions at a distance of 60 cm from the plant, and is applied every 7-10 days. During the seedling stage, each plant is fertilized with one fertilizer ball divided into four portions. As the Victoria amazonica grows, the number of fertilizer balls can be increased to 2-4 per plant per time.

[0051] Preferably, when fixing the plastic bag in the step S4, the bag opening should not be tied too tightly, so that the water in the pool can be exchanged with the water in the plastic bag, thereby eliminating the need to change the water every day.

[0052] Preferably, in S5, as the Victoria amazonica grows, the water level is gradually adjusted to maintain at 50 cm, and the water is changed every 3-5 days according to the water quality; the potting soil uses fertile pond soil, and the planting depth is preferably such that the seed shell is higher than the soil surface, and the roots must not be damaged during planting; topdressing begins 15 days after planting, and is applied once every half a month, each time using 3-5 grains of compound fertilizer pressed into the soil 5 cm away from the roots of the plant.

[0053] The mass ratio of the compound fertilizer in S3 to the decomposed organic fertilizer (chicken manure, cow manure or oil residue) is 1:5-1:6.

[0054] The pest control in S7 is mainly carried out by manually removing snails or placing larger plant leaves (such as palm leaves) on the edge of the pond at night to lure snails. When the number of snails is large, sand or soil is mixed with snail-killing amine ethanolamine salt and spread on the shallow water edge of the pond in the evening; the armyworm can be sprayed with 800 times diluted 90% trichlorfon original medicine, and aphids can be sprayed with 1000 times diluted 50% aphid pine emulsifiable concentrate for prevention and control; when brown spot disease and leaf rot of Victoria amazonica appear, methyl thiophanate or carbendazim can be sprayed for prevention and control.

[0055] When the S6 is planted out of the nursery, the seedlings with a leaf diameter of more than 50 cm are planted at a long distance. During transportation, the leaves of the Victoria amazonica seedlings should be protected with newspapers, molds, etc., and a large plastic sheet is used to pad the bottom and surroundings of the transport vehicle to ensure that water does not leak out. Then half a car of sawdust is put in and a certain amount of water is added to allow all the sawdust to fully absorb water. The sawdust will heat up after absorbing water. The Victoria amazonica must be transplanted in it after the sawdust cools down. This can avoid the loss of water in the Victoria amazonica, maintain the integrity of the leaves, and ensure a 100% survival rate and ornamental effect of the Victoria amazonica. See the picture of Victoria amazonica. Figure 1 and Figure 2 .

[0056] Comparison of the maximum diameter of Victoria amazonica leaves in different years Figure 3 As shown, it can be seen that in 2023, the maximum diameter of Victoria amazonica can reach 2.28 meters, an increase of 50cm from 2020. Figure 4 It can be seen that the method of the present invention can make the leaves of Victoria regia grow faster and bigger. Figure 5 As shown, it can be seen that the Victoria amazonica seeds obtained by the method of the present invention are numerous and full.

[0057] Example 2 Effects of Pond Cleaning and Sun-drying on the Growth of Victoria amazonica

[0058] Compared with Example 1, pond cleaning and pond drying are not performed, and the other conditions are the same.

[0059] Results comparison: It was found that after pond cleaning and drying, the landscape of the garden water body in Example 1 was improved, light transmission was increased, the growth of algae was avoided, and the growth of Victoria amazonica seedlings was beneficial (see Figure 6 ). At the same time, by cleaning and drying the pond, tilapia and golden apple snails can be removed, aquatic plants in the pond can be removed to fully expose the pond mud to the sun, increase soil fertility, and use quicklime and carbendazim to disinfect and sterilize the entire pond, which is of great benefit to the later growth and management of Victoria amazonica plants.

[0060] Example 3 Effects of different germination methods on the growth and management of Victoria amazonica

[0061] Compared with Example 1, the difference is that other methods are used to accelerate germination:

[0062] 1. Germination in a constant temperature box: Use a sharp knife to pick out the hilum on the seed coat and place it in a constant temperature box for germination.

[0063] 2. Seeds in mesh bags are exposed to shallow water for germination:

[0064] 3. Use heating rod to accelerate germination: Put the heating rod into the bucket for germination.

[0065] Compared with Example 1, the three different germination methods have different results. Figure 7 shown.

[0066] It is found that the method of Example 1 is used for germination. The black bag absorbs heat and is immersed in shallow water at the same time. The bag mouth should not be tied tightly, so that the water in the bag can be freely exchanged with the water outside the bag. There is no need to change water frequently, there is no need to pick out the hilum on the seed coat, no other devices are needed, and there is no need to change water frequently. It is convenient and fast, and the buds obtained are uniform. In the constant temperature box, the seeds are easily infected by pathogens and rot and mold; the gauze bag seeds are exposed to shallow water for germination. The gauze bag cannot gather heat. After the water is exchanged, the temperature in the bag is lower, and the germination is slow and uneven. When the heating rod is tried for germination, it is necessary to change water in 2-3 days. If the water quality in the bucket is not changed, it is easy to grow moss, and the seeds that have just been exposed to white are easy to rot. Frequent water changes are troublesome, and the most important thing is that the germination is not uniform, which has a great impact on the later stage of Victoria amazonica seedling cultivation, growth, flowering and fruiting.

[0067] Example 4 Effects of different fertilization methods on the growth and management of Victoria amazonica

[0068] Victoria amazonica needs sufficient fertilizer during its growth period. Topdressing begins half a month after the seedlings are planted and survive. The main application is raw soil, compound fertilizer, and urea in a ratio of 1:2:2, and they are kneaded into fertilizer balls with a diameter of 5-8cm. When using, insert the fertilizer balls into the soil around the roots of the plants from different directions. Time: 7-10 days / time Depth: 10-30cm Distance: 60cm. Results are shown in Figure 8 B.

[0069] Compared with Example 1, two other methods were also used: newspaper wrapped compound fertilizer and sheep manure (results see Figure 8 C) Use shade nets to wrap compound fertilizer and unbroken sheep manure;

[0070] The results showed that when compound fertilizer and unbroken sheep manure were wrapped in shade nets, hard organic fertilizers such as sheep manure were not easily absorbed by plants. Figure 8 A: The fertilizer balls made by the formula of Example 1 are easy to operate when fertilizing, easily absorbed by plants, and fertility is not easily lost. The results are shown in Figure 8 B. Using newspaper to wrap compound fertilizer is not easy to operate when fertilizing. When the newspaper comes into contact with water, the fertilizer is easy to melt and the fertility is lost quickly. Figure 8 C.

[0071] Example 5 Prolonging the Vitality of Victoria Victoria

[0072] The new root system of the Victoria amazonica grows at the base of each new leaf. As the stem of the Victoria amazonica grows slowly, the new root system cannot contact the soil, and the old root system will slowly rot. If no measures are taken, the Victoria amazonica plant will float and die in mid-to-late October each year. If the method in Example 1 is used to cultivate the roots of the Victoria amazonica from the end of September to the beginning of October each year, the growth period of the Victoria amazonica plant can be extended by 180 days. Fig. 9 ,from Fig. 9B shows that the new roots of the Victoria amazonica grown in the newly cultivated soil grow at the base of each leaf, which extends the growth period of the Victoria amazonica.

Claims

1. A method for raising and cultivating Victoria amazonica seedlings in the open air, comprising the following steps: S1 Preparation of planting pond: When the temperature reaches 25℃, clean and dry the pond, and remove all aquatic plants, fish and golden apple snails in the pond; after cleaning, fully expose it to the sun for 5-7 days, and then disinfect and sterilize it; S2 Planting baskets (pits) and their settings: Planting baskets (pits) are set up in places with deep water levels. The diameter of the planting baskets (pits) is 1.5-2m, and the height is greater than 70cm. The distance between the two baskets is at least 5-6m, and the top of the planting baskets (pits) is 1-1.5m from the water surface; S3 Base fertilizer preparation: Fertile pond mud is placed at the bottom of each planting basket (pit), and then compound fertilizer and decomposed organic fertilizer are added; the organic fertilizer includes chicken manure, cow manure or oil residue; S4 seed germination: Use black plastic bags to soak in shallow water and expose to strong light for germination. When the temperature reaches above 25℃, find a sunny location in the pond, put the seeds into the black plastic bag, immerse it in clean water and fix it at a depth of 10-15cm. Leave it for 10-15 days until the seeds germinate 1-2cm. S5 Seedling cultivation: Soak the germinated seeds in a bucket with a water depth of 10-15cm, and cultivate the seedlings in a sunny environment. When the primary seedlings grow 2-3 leaves and 2-4 roots, move them into a flower pot with a diameter of 10-15cm; after planting, put them in water so that the leaves float on the water surface; S6 Planting: When the leaf diameter reaches 15-30cm, it can be planted out of the nursery. Remove the small pot for seedlings. The planting depth should not be too deep. It is better to bury it to the height of the soil ball in the small flower pot when the seedlings are grown. Do not bury the stem tip of the Victoria amazonica in the soil. Topdressing begins 15 days after the seedlings are planted, using fertilizer balls; S7 Daily management, pruning of branches and leaves, and control of diseases and pests: Prune branches and leaves in time after entering the growth period. When pruning, cut off old leaves, yellow leaves, and appropriately cut off newly grown young leaves, leaving the growing leaves, and maintain 8-10 leaves per plant; and promptly remove snails and control diseases and pests.

2. The method for raising seedlings and cultivating Victoria amazonica in the open air according to claim 1, wherein: The S4 seed germination method can be replaced by constant temperature box germination: use a sharp knife to pick off the hilum on the seed coat, put the seeds in a culture dish, submerge the seeds in water, put the culture dish in a 28°C constant temperature box, and change the water once a day.

3. The method for raising seedlings and cultivating Victoria amazonica in the open air according to claim 1, wherein: The mass ratio of the compound fertilizer in S3 to the decomposed organic fertilizer (chicken manure, cow manure or oil residue) is 1:5-1:

6.

4. The method for raising seedlings and cultivating Victoria amazonica in the open air according to claim 1, wherein: In the step S6, the fertilizer balls are made by mixing soil with good viscosity, compound fertilizer and urea in a ratio of 1:2:2 and kneading them into fertilizer balls with a diameter of 5-8 cm.

5. The method for raising Victoria amazonica seedlings and cultivating them outdoors according to claim 1, wherein: In the step S6, during topdressing, fertilizer balls are inserted into the soil 10-30 cm deep at a distance of 50-60 cm from the plants from different directions, and topdressing is performed once every 7-10 days. During the seedling stage, each plant is topdressed with one fertilizer ball divided into four portions. As the Victoria amazonica grows, the number of fertilizer balls can be increased to 2-4 per time per plant.

6. The method for raising seedlings and cultivating Victoria amazonica in the open air according to claim 1, characterized in that: When fixing the plastic bag in the step S4, the bag mouth should not be tied too tightly, so that the water in the pool can be exchanged with the water in the plastic bag, thereby eliminating the need to change the water every day.

7. The method for raising Victoria amazonica seedlings and cultivating them outdoors according to claim 1, wherein: In the S5, the water level is adjusted to maintain at 50 cm as the Victoria amazonica grows, and the water is changed every 3-5 days according to the water quality; the potting soil is fertile pond soil, and the planting depth is preferably such that the seed shell is higher than the soil surface, and the roots must not be damaged during planting; topdressing begins 15 days after planting, and is applied once every half a month, with 3-5 grains of compound fertilizer pressed into the soil 5 cm away from the roots of the plants each time.

8. The method for raising seedlings and cultivating Victoria amazonica in the open air according to claim 1, characterized in that: At the end of September to the beginning of October every year, the roots of Victoria amazonica should be fertilized with soil.

9. The method for raising Victoria amazonica seedlings and cultivating them outdoors according to claim 1, wherein: The pest control in S7 is mainly carried out by manually removing snails or placing larger plant leaves (such as palm leaves) on the edge of the pond at night to lure snails. When the number of snails is large, sand or soil is mixed with snail-killing amine ethanolamine salt and spread on the shallow water edge of the pond in the evening; the armyworm can be sprayed with 800 times diluted 90% trichlorfon original medicine, and aphids can be sprayed with 1000 times diluted 50% aphid pine emulsifiable concentrate for prevention and control; when brown spot disease and leaf rot of Victoria amazonica appear, thiophanate-methyl or carbendazim can be sprayed for prevention and control.

10. The method for raising seedlings and cultivating Victoria amazonica in the open air according to claim 1, characterized in that: When the S6 is transplanted, when the mature seedlings with a leaf diameter of more than 50 cm are transported over long distances, the leaves of the Victoria amazonica seedlings should be protected with newspapers, molds, etc., and a large plastic sheet should be placed on the bottom and around the transport vehicle to ensure that water does not leak out. Then, half a vehicle of sawdust is put in and a certain amount of water is added to allow all the sawdust to fully absorb water. The sawdust will generate heat after absorbing water, and the Victoria amazonica seedlings must be transplanted in it after the sawdust cools down.

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