Origin and distribution
Carya cathayensis is native to North America. Long before Europeans immigrated to America, it was already the main natural economic forest for local Indians, collecting wild fruits for food. It was not until 1850 that people began to cultivate fruit trees and select excellent varieties, which developed rapidly; /kloc-large-scale planting at the end of 0/9 and the beginning of the 20th century; It developed rapidly after the 1950s. China was first introduced from the United States for nearly a hundred years. It was not planted in Shaoguan, Xiamen, Fujian, Hangzhou, Jiangsu, Nanjing, Jiangyin, Huai 'an and other places until the 1960s, but it failed to develop into commercial production.
Features and characteristics
The height of a tree is generally 20-30 meters, up to more than 50 meters. The bark is deeply cracked and dark brown. Buds are scaly, and buds and shoots are pubescent. Odd pinnate compound leaves, 9 ~ 17 leaflets. Male flower buds 3 kill a bunch, with almost no total peduncle and hairy anthers; The female spike is erect, and the female flower is 2 ~ 10. Nut has a 4-sided involucre, short round or rectangular, smooth surface, light yellow brown, with black powdery spots.
The root system of Carya cathayensis is well developed, and the lateral roots often extend to more than twice the radius of the crown. The root system is generally distributed in the soil layer with a depth of 18 ~ 65cm (Li Daode, Liu Zhenya).
Medium. Seedling trees 1 1 ~ 13 years begin to bear fruit, and grafted trees begin to bear fruit in 2 ~ 3 years, with an economic life of 50 ~ 80 years. The yield per plant is generally about 50 kg, and the highest yield can reach more than 100 kg. Like Carya cathayensis, there are three types of flower branches, namely: female flower branches, with only female inflorescences at the top of new branches and no male inflorescences at the bottom; Male flower branches, with male inflorescences only at the lower part of the new branches and no female inflorescences at the top; A mixed branch of male and female flowers, with female inflorescence at the top of the new branch and male inflorescence at the bottom. Generally, the new branches that bear fruit in that year no longer form mixed buds, and then form female flower buds or hermaphroditic flowers in the second year, and then bear fruit in the third year. As far as a branch is concerned, it often bears fruit every other year. Similar to Carya cathayensis, the new shoots are concentrated in the branches, and the middle and lower parts are exposed, which leads to the position moving to the periphery of the crown and the cavity is empty. Hidden buds have long life, easy to shoot new branches and strong regeneration ability. It takes 150 ~ 180 days from flowering to fruit ripening, and the growth period is 250 days.
Carya cathayensis likes warm, deep soil, rich humus, moist and well-drained sandy soil. The suitable annual average temperature is 15 ~ 20℃, the annual precipitation is 1000 ~ 2000mm, and the zone of 30 N ~ 35 N is the best. The annual frost-free period should be more than 180 ~ 200 days, and the pH value can grow well in the range of 5 ~ 8. The east or southeast of the hillside should be sunny.
principal item
There are more than 500 varieties of hickory, most of which are selected from wild trees. According to the variety source and adaptability, it can be divided into three varieties groups: drought tolerance, humidity tolerance and cold tolerance. According to the fruit size, it can be divided into two categories: large fruit species (the number of nuts per kilogram is below 140) and small fruit species (the number of nuts per kilogram is above 140). The main varieties (strains) are: ① Drum Tower. Produced in Nanjing, Jiangsu. Nuts are oval, with extremely thin shells, each kilogram 130 grains; The grain yield is 50.6% and the oil content is 63.9%. The meat is tender, high quality and high yield. 65438+1expires in late October. Don't worry. Produced in Nanjing, Jiangsu. Nuts are oval, per kilogram 128; The grain yield is 42.3% and the oil content is 68.4%. The shell is slightly thicker, the kernel is enlarged, the quality is above average, and the yield is high. 65438+1expires in late October. ③ Zhongshan. Produced in Nanjing, Jiangsu. Nuts are oval, per kilogram 142; The grain yield is 54.3% and the oil content is 73.4%. The shell is extremely thin, kind, sweet and of medium quality. 65438+1expires from late October to early October. ④ Nanjing 1. Produced in Nanjing, Jiangsu. The number of nuts per kilogram is166; The grain yield was 57.6% and the oil content was 74.3%. Very thin shell, kind, high quality output. ⑤ Curtis. Made in America. It is the main variety of small fruit species. The base of the nut is slightly enlarged and gradually tapers to the top, with 204 nuts per kilogram; The grain yield is 54%, and the oil content of grain is 69%. The shell is extremely thin, the kernel is quite thick, the aroma is rich and the quality is high. 6. Stuart. A variety widely cultivated in the United States. Nuts are oval, each kilogram 1 12; The grain yield is 45% and the oil content of grain is 72%. Thick shell, big kernel, high quality and high yield. 7 Mahan. Made in America. Nuts are oval or obovate, 80 per kilogram; The grain yield is 40% and the oil content of grain is 66%. Thick shell, medium quality and medium output. Today Shelley (Shirley). A famous variety in the eastern United States. Nuts are oval or obovate, per kilogram 160 grains; The grain yield is 55%, and the oil content of grain is 72%. The shell is extremely thin, the kernel is fat, fragrant and of medium quality.
Key points of cultivation techniques
In addition to sowing and grafting, lateral roots with a diameter of more than 0.5 cm can be cut into 5 ~ 10 cm for cutting propagation, which is easy to survive and grow well. When the garden is built, the plant spacing is 6×6 or 7×8 meters, and intercropping in the early growth stage is feasible. The suitable planting period is in the first half of June165438+1October, and pollination varieties need to be configured.
In the first year after planting, the plant grows slowly and needs little fertilizer; Fertilization began in the second year after planting, and vegetables and green manure crops were intercropped among young trees. Base fertilizer is mainly applied to mature trees in autumn and winter, and topdressing is applied once before germination, after flowering and during flower bud differentiation in spring.
Carya cathayensis has strong dryness and obvious layering. The terminal buds of young branches often produce strong branches, and the growth of the central trunk of mature trees becomes weaker, while the growth of the surrounding main branches becomes stronger, and the crown changes from conical to round or round. It is appropriate to use the shape of the trunk with variable edges, and the first layer of main branches on the trunk is about 1 m from the ground.
The main pests and diseases are branch blight, brown spot, powdery mildew, giant salamander, leopard moth, scarab, thorn moth, longicorn beetle and so on. So pay attention to prevention and control.
economic value
Carya cathayensis is one of the main dried fruits in the world, and its nuts are rich in nutrition. Every 100g contains protein 12. 1g, 70.7g of fat and 0/2.2g of carbohydrate. Can be eaten raw, used to make all kinds of sweets and cakes, and is also an oil tree species. Wood is tough and fine-grained, which can be used for carving and making high-grade furniture. It is a good material for military industry. It is also an excellent tree species for street trees and landscaping.