The scientific name of blueberry is Vaccinium, which belongs to Vaccinium of Ericaceae. Blueberries are perennial deciduous or evergreen shrubs with blue, nearly round fruits and tiny seeds. The pulp is delicate, sweet and sour, and fragrant. It can be eaten fresh or processed into fruit juice, fruit juice, fruit wine, etc. Blueberry cultivation first began in the United States, and almost all native blueberry varieties in China are wild and not suitable for planting. More than 20 years ago, China began to introduce foreign excellent varieties, and more than 20 varieties have been introduced so far, but the scale is not large.
Besides conventional sugar, acid and Vc, blueberry fruit is also rich in VE, VA, VB, SOD, arbutin, protein, anthocyanin, dietary fiber and mineral elements such as K, Fe, Zn and Ca. According to the analysis of Small Berry Research Institute of Jilin Agricultural University, the content of anthocyanin pigment in its fruit is as high as 163 mg/ 100 g, and the content of fresh fruit VE is 9.3μ g/100g, which is several times or even dozens of times that of other fruits such as apples and grapes. The content of total amino acids is 0.254%, which is higher than that of hawthorn rich in amino acids. In addition to fresh food, blueberry fruit also has strong medicinal value and nutritional and health care functions. International Food and Agriculture Organization lists it as one of the five health foods for human beings, and its market prospect is very broad. In order to promote the development of blueberry industry in our province, its cultivation techniques are introduced as follows.
1 Garden selection
Blueberry has a wide planting range, and suitable varieties can be selected according to the local climate, but it is not suitable for development in the northern region with little snow and frost. The slope of the selected garden should not exceed 10 degree; The pH value of soil is 4.0 ~ 5.5, and the optimum range is 4.3 ~ 4.8. The content of soil organic matter is not less than 5%; The soil is loose, well ventilated and moist, but there is no water accumulation. Excessive soil pH is an important factor limiting blueberry planting. Too high pH value often leads to iron deficiency, poor growth, low yield and even plant death. When the pH value is greater than 5.5, it is necessary to apply sulfur powder or aluminum sulfate to reduce the pH value. Sulfur powder should be applied before planting 1 year or at least in the planting year, but it generally does not work in the same year after applying sulfur powder.
2 Garden preparation
After the garden is selected, the green manure should be deeply ploughed with a depth of 20 ~ 25 cm one year before planting, and the soil should be prepared after deep ploughing and ripening. Before planting, improve the soil that does not fully meet the requirements to facilitate the growth of blueberries.
3 Colonization
Blueberries can be planted in spring and autumn, and the survival rate of autumn sowing is high, so spring sowing should be sooner rather than later. The plant spacing of dwarf blueberries is usually 2×2 m or 1.5×3 m, that of tall blueberries is 1.2×2 m and that of dwarf blueberries is 0.5 ~1×1m. Dwarf blueberries have no white flowers, so it is best to configure high-bush blueberries as pollination varieties. The white flower setting rate of blueberry with high cluster and low cluster is higher, but the fruit quality and yield can be improved by configuring pollination trees. The distribution ratio of main cultivated varieties to pollinated varieties is 1∶ 1 or 1∶2.
4 Soil, fertilizer and water management
4. 1 soil management
Blueberry root system is shallow and slender, and there is no root hair, so it requires loose soil and good ventilation.
4. 1. 1 Farming method can be used from early spring to August, but it is not good for its overwintering after autumn. Clear tillage is usually used to plant Vaccinium myrtillus in sandy loam. The suitable cleaning depth is 5 ~ 10 cm, which is easy to damage the root system.
4. 1.2 Planting grass between rows and using herbicides between rows. Compared with clear tillage, planting grass is also beneficial to increase yield, which has the advantages of maintaining soil moisture and facilitating mechanized operation.
4. 1.3 Soil mulching is widely used in blueberry production, which has many functions, such as increasing soil organic matter, improving soil structure, regulating and maintaining soil moisture, lowering soil pH value, controlling weeds and so on. Covering the soil with 5 ~ 10 cm sawdust can increase the yield by 30% and the weight of single fruit by 50% in three years. Crop straws such as leaves and straws can also be used, but the effect is not as good as sawdust.
4. 1.4 Weeding chemical herbicides are widely used in blueberry production. This is because the cost of manual weeding is high, and it is easy to damage the roots, especially for the planting of dwarf blueberries. Because the roots are strung together, the whole orchard will be connected after a few years, and it is impossible to weed manually. Herbicides commonly used in blueberry orchards are diuron, simazine, chlorpheniramine, 2,6 dichlorobenzene, glyphosate and paraquat.
4.2 Fertilization
The effect of applying nitrogen, phosphorus and potassium compound fertilizer to blueberry is better than that of applying chemical fertilizer alone. The ratio of nitrogen, phosphorus and potassium fertilizer is1:1:1. Blueberries are sensitive to chlorine. Do not use chlorine-containing fertilizers such as ammonium chloride and potassium chloride. Methods Ditching method can be used, and the suitable depth is 10 ~ 15 cm. Dense blueberries are planted in the garden and connected together, mainly by sowing. Fertilization should be carried out before germination in early spring, or 1 time at berry maturity. The amount of fertilization must be determined according to soil fertility and tree nutrition.
4.3. Irrigation
Blueberries have shallow roots and like to be wet, so they need to be irrigated in time. Pay attention to water source and water quality in blueberry irrigation. Deep well water usually has high pH value and high content of sodium and calcium. Long-term use will affect the growth and yield of blueberries. During irrigation, the pH value can be adjusted to about 4.5 with sulfuric acid before irrigation, but acidic water should be irrigated every three times.
5 pruning technology
5. 1 Pruning of High-bush Blueberries
5. 1. 1 Pruning at the young tree stage is mainly to remove flower buds, with the purpose of expanding the crown, increasing the number of branches and promoting the development of roots. In the spring of the second and third years after planting, the weak branches become thinner, and in the third and fourth years, the crown is still mainly enlarged, but it can bear medium fruit. Generally, the plant yield should be controlled below 1 kg in the third year, with strong branches as the main fruit.
5. 1.2 Pruning of mature trees At this time, pruning is mainly to control the height of trees and improve the lighting conditions, with thinning of branches as the main method, and thinning of over-dense branches, over-thin branches, branches of diseases and insect pests and roots. The root activity is stronger than that of open varieties when thinning branches; Vertical varieties go to the center to dry, open the skylight and leave the middle branches. The best fruiting age of big branches is 5 ~ 6 years old, so they should be retracted and updated in time. Weak branches erase flower buds and make them stronger. Adult trees have a lot of flowers, so some buds need to be cut off. Generally, each strong branch leaves 2 ~ 3 flower buds.
5.2 Pruning of Dwarf Blueberries
5.2. 1 Fire shears burn all the above-ground parts during dormancy, sprout new branches again, form flower buds in that year, and blossom and bear fruit in the next year. After that, it will be cut by fire every two years, and it has always maintained vigorous branches.
5.2.2 The stubble should be trimmed before germination in early spring. The stubble above the ground should be sawed off from the base of the plant, and the sawed branches should be left in the orchard, which can cover the soil and improve the organic matter.
6 harvest
Dwarf blueberries have the same maturity, and the early-maturing fruits are not easy to fall off, so they can be harvested together after all the fruits are ripe. After the fruit is harvested, the dead branches, fallen leaves, stones and other sundries are removed and put into a container. The ripening period of high-cluster blueberry fruit is different, and it usually takes 20 ~ 30 days to harvest, usually once a week/kloc-0. Fruit should be picked manually when it is fresh and harvested mechanically when it is used for processing.