Cultivation and management techniques of young litchi fruit trees

Litchi belongs to the disease-free family, which is native to China and is one of the four famous fruits in southern China. It has been cultivated for more than 2000 years. Based on the experience of litchi cultivation techniques, it is concluded that the growth characteristics of young litchi trees are as follows: (1) low branch order; (2) large shoot growth; (3) vigorous root growth; (4) early flowering and low proportion of female flowers. The female florescence is short, and it is difficult to set fruit. (5) the level of nutrient accumulation is low and the germination ability of multiple buds is strong. In view of the above five characteristics, we should pay attention to the following aspects in management, give full play to our strengths and avoid weaknesses, achieve high and stable yields, and have a bumper harvest every year. First, master the six principles 1. In fertilization, it is necessary to reduce the proportion of nitrogen fertilizer, increase the application of phosphorus and potassium fertilizer, supplement trace elements such as boron and magnesium, control the shoot growth, improve the shoot quality, and make the shoot strong, sufficient and full. two。 The autumn shoots were cultured twice to promote the early ripening of the last autumn shoots and accumulate enough floral substances (carbohydrates, proteins and some hormones) for flower bud differentiation. 3. After the last autumn shoot matured, the growth was controlled, the winter shoot did not germinate, the leaf color turned red, and the flower bud differentiation was promoted. 4. Fertilizer before flowering, especially available nitrogen, should not be applied early, but should be applied after the bud. 5. Trim should be light. 6. The prevention and control of diseases and insect pests should be timely. Second, the implementation of four measures (1) to cultivate sturdy and excellent fruiting mother branches. The time and frequency of autumn shoot: the second time is from late July to early August, and the second time is from early September to early October. It is better to control the proximity of a tip from the end of August to the first ten days of September. two。 Apply good fertilizer to promote shoots. This is the fertilizer applied before and after fruit harvesting, mainly to promote the rapid recovery of fruiting tree potential, timely extraction of strong autumn shoot fruiting mother branches. This fertilization is the key fertilizer to overcome the big and small years, mainly available nitrogen fertilizer, generally accounting for more than 50% of the annual fertilizer application. For trees that grow vigorously and bear little fruit, they should consider the amount of weight loss or not apply this fertilizer to avoid winter shoots. 3. Pruning: pruning of young trees should be focused on the first 3-4 years, and after 4-5 years, attention should be paid to the retention of secondary main branches and lateral branches. The pruning principle of young trees is light cutting. After the first autumn shoot matured, the second autumn shoot germinated before, cut off disease and insect branches, over-dense branches, shade branches, weak branches, overlapping branches, withered branches, black leaves, cinnamon-flavored shade branches can also bear fruit, can stay more appropriately. It is appropriate to leave about 40 autumn shoots per square meter. The pruning of the fruit tree should be completed within one month after fruit harvest. (2) several specific prerequisites are needed to control growth and promote flower bud differentiation, namely, timely placement of autumn shoots, thick and strong shoots, mature shoots, accumulation of enough floral substances with flower bud differentiation, and non-germination of winter shoots. third, there is a continuous low temperature of 010 degrees Celsius in winter. With the above premise, coupled with artificial physical and chemical assistance, flower bud differentiation is more normal and safe. 1. Make water and fertilizer, expand holes and cut roots, or hoe 15cm to 20cm deep in the tree plate, after the autumn shoots are ripe. two。 During the period of ring cutting or ring peeling, the flower buds of middle and late mature species differentiated from November to February of the following year, and the peak period was from December to the end of January. during this period, a ring cutting or spiral ring peeling was carried out in a sunny day without north wind, and the mouth was peeled off by 2 mm. 3. Spraying Guoling once or twice after autumn shoot maturing, or spraying 40% ethephon 20 ml flushing water 20 kg plus B9 continuously from late November to December can help to inhibit winter shoot germination, promote flower bud differentiation and increase the proportion of female flowers. (3) Flower and fruit protection should be based on the interaction between vegetative growth and reproductive growth of litchi trees to select the type and quantity of fertilizer and various artificial auxiliary means to achieve high yield. 1. Fertilization: mainly organic fertilizer, supplemented by chemical fertilizer, with appropriate amount of boron, magnesium, zinc, molybdenum and other trace elements. In order to have a reasonable and appropriate amount, trees with a yield of 100 kg generally need 3-4 kg of urea, 2-3 kg of potassium, 2-3 kg of phosphorus and 2-3 kg of lime. Among them, the main fertilizer for promoting shoot is nitrogen fertilizer and the combination of phosphorus and potassium. Equal emphasis on N, K and P as flower-promoting fertilizer and proper amount of lime. The main fertilizer of protecting fruit and strengthening fruit was potassium, combined with N and P. two。 Release bees for pollination, or artificial pollination. 3. Drench water in high temperature and drought and spray clean water in the morning. 4. Spray carotene, spray fruit tralin or "920" after 2 / 3 Xiehua, flush 30kg / g, or a week before the second physiological drop, ring-cut to protect the fruit. (4) in the prevention and control of diseases and insect pests, it is necessary to control bugs, stalk borer and frost Phytophthora in time. 1. Bugs, also known as stinky bugs, smelly fart spicy. The control methods of the bugs are as follows: (1) in the period when the temperature drops obviously in winter, especially when the temperature drops below 50 ℉, we can make use of the fake death characteristics of the adults to shake the litchi branches so that the adults who spend the winter on the leaf green can be frightened to fall to the ground, and then swept and killed. (2) Trichlorfon was sprayed once before and after the oviposition of adults and during the occurrence of larvae. The first time is about early March, and the second is from late April to early May. (3) the flat-bellied wasp (a kind of artificially propagated parasitoid) can be released once in early spring and once again in the middle of May to control insects. two。 The control methods of stem borer generally have two points: one is to clear the garden in winter, to sweep the fallen leaves, fruits and weeds, and to eliminate the source of overwintering insects; the other is to spray 1000 times with trichlorfon diluted with water after full bloom. 3. The pathogen of downy Phytophthora is a fungus. The prevention and control methods for it are as follows: (1) clearing the garden in summer to eliminate the source of bacteria; (2) in the early stage of fruit damage, spraying 40% aluminum ethyl phosphate or ammonium benzoate or metalaxyl 1000 times; and (3) in orchards that have been seriously damaged, spray 1000 times of Redusa or 1000 times of metalaxyl in the flower bud stage and small fruit stage.