Pomegranate is an excellent tree species beautified in courtyard greening, because of its short clump, beautiful leaves, long flowering period, unique style and rich ornamental value. In addition, pomegranate is barren and salt-tolerant, and it is also a good tree species for developing economy in gentle slope hills and coastal beaches.
(2) Main types and varieties
Pomegranate belongs to pomegranate family. There is only one kind of pomegranate in fruit tree cultivation, namely pomegranate, as well as ornamental pomegranate, small pomegranate and other varieties.
There are many varieties of pomegranate cultivated in China. According to the flavor of seeds, there are two kinds of sweet and sour; According to the color and thickness of peel, there are white skin, green skin, red skin, brown skin, thin skin and thick skin. According to the color, hardness and size of seeds, there are jade seeds, agate seeds, soft seeds and big seeds. Varieties are basically named according to the above characteristics, and some varieties may have the same thing with different names because they are not sorted out. The main varieties in Huaibei area and the middle and lower reaches of the Yangtze River are: vermicelli, coarse green husk, stupid pomegranate, agate seed and jade seed in Suixi and Huaiyuan, Suzhou, Anhui; Dahongpao and Ertongpi in Tongshan, Jiangsu; Green pomegranate and red pomegranate in the suburbs of Nanjing; Dahongpitan (Hongyi 1), Daqingpitan and Shandong Yixian Soft-hearted Pomegranate.
When selecting varieties, we should not only consider the advantages and disadvantages of fruit size and quality, but also comprehensively evaluate the local adaptability, pests and diseases, whether the fruit is easy to crack, storage resistance and so on.
(3) Growth and fruiting habits
Pomegranate is a small deciduous tree or shrub. The root system is shallow in the soil, with a small distribution range, and it is easy to sprout roots and tiller. There are many branches on the ground, and the tips of branches often turn into needles. In the Jianghuai Valley, bamboo shoots can be harvested 2-3 times a year, followed by spring shoots, summer shoots and autumn shoots. After each new shoot sprouted, the long branches at the tip expanded to crown, and the short branches with full development in the middle and lower parts could be transformed into fruiting branches with mixed buds at the front end. The tips of long branches and long branches are mostly self-withered, without terminal buds. The hidden buds of pomegranate have a long life. When the big branches droop, they often produce upright branches from the back and naturally renew the crown.
Pomegranate blooms and bears fruit in early spring by pumping short branches of mixed buds. Therefore, from the beginning of spring, the branches of Zhixia began to sprout, and pomegranate trees kept flowering from spring to summer, and the flowering period often lasted for two or three months. Fruiting branches from spring shoots, especially single flower fruit branches from the terminal buds of mother branches, are the most reliable. In summer and autumn, the shoots and fruiting branches bloom late, and the fruits are often poor, or the flowers are not fruitful. After the fruiting branch bears fruit, shoot new branches from the lower part of the mother branch in the second year, and form new fruiting mother branches again. If it is borne by the lateral flowers in the leaf juice, the top can continue to extend and grow. When pomegranate bears too much fruit per plant, there will also be the phenomenon of big and small years.
One or several flowers are planted between the top of the new bearing branch and the axils of the lower leaves, and the top flower has the highest fruit setting rate. Flowers are bisexual, but degenerate flowers often appear. According to the survey, generally speaking, the complete flowers of 20 ~ 30-year-old plants only account for about 10% of the total flowers, and the 50 ~ 60-year-old plants only account for about 5%. In the degenerated flowers, the pistil degenerates to varying degrees until it basically disappears. This can be distinguished from the appearance before flowering. The lower end of normal calyx is round and blunt, and the knot strength is high; The degenerated calyx is pointed at the lower end and cannot bear fruit. This is an ineffective flower that often falls off. Early thinning of degraded flowers can save tree nutrients and improve the fruit setting rate of complete flowers.
The organ degeneration of pomegranate flowers is related to varieties and tree nutrition. Trees with strong vigor and short fruiting branches have fewer degenerated flowers and more normal flowers; The tree is weak, the mother branches are slender, and the flower organs on it are seriously degraded.
(4) Characteristics of cultivation techniques
1. Propagation and planting pomegranate branches are easy to take root. Cutting, layering and branching can be used to propagate seedlings, and cutting is often used in production. The best cuttings are complete biennial branches. The cuttings are about 20 cm long, the lower ends are cut into horse ears, and the upper branches are cut off. Strong annual branches can also be used as cuttings, and the survival rate of old branches is low, which is not suitable for application. When the temperature stops rising steadily in the middle and late March, hard cutting should be carried out in Huaibei area and Yangtze River basin. If the ground is covered with plastic film (the cuttings are exposed), it is beneficial to improve the ground temperature. It can take root and survive about one month after insertion. In addition, the survival rate of semi-lignified branches in the early growth stage is also very high when green branches are used for cutting in rainy season.
Pomegranate is not strict about planting area. The planting distance depends on the variety growth potential and soil fertility. Use (3 ~ 5) meters and (3 ~ 4) meters per row. Well-managed pomegranate trees blossom and bear fruit in 3 ~ 4 years after planting, and can enter the full fruit stage in about 10 years.
2. Turtle-shaped pomegranate trees with unconstrained growth often have lush foliage and messy branches on the crown. During plastic surgery, the stem can be left upward as required, and the other sprouting strips are often cut off, and the stem is cut short at 80 cm ~ 100 cm, and the upper part is divided into 3 ~ 4 main branches, and gradually cultivated into a natural round-headed crown. It is also possible to select 3-5 branches from the near surface for cultivation without leaving the trunk to form a multi-stem cluster crown.
Pomegranate trees like light. On the basis of plastic surgery, the roots and tillers are cut off every autumn, and the transverse branches, over-dense branches, long branches and thin branches in the crown are thinned to keep the branches in the crown sparse and uniform, and the ventilation and light transmission are good. Pay special attention to some varieties with strong branches. Pomegranate trees are rarely cut down except for a few short branches. For fruiting mother branches, the upper part can be cut off to promote regeneration. In case of drooping branches, they should be trimmed properly. When the tree is aging, it will cut off some aging branches more violently, and at the same time, with the help of increasing fertilization water, the crown will be gradually updated by using the strong sprouting strips of hidden buds to make it continue to bear fruit.
3. The fertilizer and water management and the formation of degenerated flowers of antifreeze pomegranate are directly related to the storage nutrition of trees in autumn. Applying base fertilizer and available nitrogen in autumn can greatly increase the proportion of complete flowers. In addition, strengthening leaf protection in autumn has the same effect as girdling and girdling young flourishing trees, thus improving fruit setting rate. Spraying 500 parts per million (500PPm) gibberellin solution at full flowering stage is particularly effective for improving fruit setting rate and promoting young fruit development. Topdressing was applied before and after spring germination and during the rapid growth period of fruits. The garden soil should be kept dry half a month before the fruit ripens, so as to improve the storability of the fruit and avoid cracking. The pomegranate orchard often cultivates and loosens the soil, which can make the peel beautiful in color and improve the quality and flavor. When there is no irrigation condition in drought, you can cover the tree tray with grass to prevent drought. When the flowering and fruiting of leafy pomegranate trees are delayed, nitrogen and phosphorus can be controlled, and local ditching and root cutting can be carried out, or 0. L% paclobutrazol solution can be sprayed to promote flowering.
Pomegranate likes warm climate. Although it can withstand short-term low temperature during hibernation, it is not resistant to freezing. When the temperature drops to-15 degrees-17 degrees in winter, freezing injury may occur. In winter in Huaibei area, anti-freezing work should be done well. The root system of pomegranate tree has strong cold resistance, and the rhizosphere soil can effectively prevent freezing in winter. Once the ground freezes, cut off the frozen part and add fertilizer water, that is, new branches can germinate from the rhizosphere again, and production can resume after 3 ~ 4 years. If conditions permit, you can also use straw and plastic film to bind branches for protection.
(5) Main pests and diseases and their control
There are few pests and diseases in pomegranate, and the common pests and diseases are mainly dry hospital disease, peach moth, pomegranate stem window moth and so on.
(1) Dry rot: it harms new fruits, flowers and fruits, resulting in a large number of fruits rotting during storage. In production, from germination to flowering, the pomegranate trees with serious diseases were sprayed with Bordeaux solution with lime equivalent of 160 ~ 180 times to protect new shoots and flowers. Spray continuously for 2 to 3 times every15 to 20 days.
(2) Peach moth: It mainly uses its characteristics of laying eggs and bearing fruit at the junction of pomegranate sepals and two fruits. You can use 1000 times of 50% chlorpyrifos or 90% trichlorfon to make cotton balls to block the calyx tube, or spray these parts for l ~ 2 times and remove the fruit manually.
(3) Pomegranate stem window moth: mainly cut off the insect tips and burn them in time. Spraying 2.5% triadimefon 3000 times during the peak period of egg incubation, and killing the larvae in the damaged branches of 2-3 years old with drugs.
(6) harvesting and storage
Pomegranate fruit maturity varies from tree to tree and should be harvested in batches. The skin color of fully mature fruit becomes bright, the color of colored varieties is uniform on the whole fruit, the color difference between yin and yang is reduced, and some varieties have more and more obvious prismatic protrusions on the side of the fruit. Choose sunny days for harvesting.
The storability of fruits varies greatly with variety maturity and peel thickness. Early-maturing varieties and thin-skinned varieties are not resistant to storage and should be sold together. Mid-and late-maturing varieties, especially those with thick skin and heavy sour taste, can be properly stored to extend the supply as long as they are fully mature.
A small amount of pomegranate can be stored in the urn, mixed with wet sand with water content of about 5%, and the handle is erected in the middle to facilitate ventilation. Cover with a layer of wet sand and seal it. Can be taken as needed and kept fresh for a long time. When storing in large quantities, it can be stored indoors or by digging wells. Check every 15 ~ 20 days during storage, and it can be stored for 2 ~ 3 months. According to the test, the single fruit packed in household plastic bags is also very effective, and the shelf life is more than 50 days. If the fruit is soaked in 50% carbendazim 1000 times solution or preservative No.2 1000 times solution 10 minute before packaging, then it is taken out and dried before packaging, the preservation effect is better.