Longan is a perennial evergreen fruit tree. Once planted, the root system continuously and selectively absorbs certain nutrients from the soil in the root zone over a long period of time. This tends to cause deficiencies of certain nutrients. Therefore, constant supplementation of nutrients is needed in production.
Proper fertilization is one of the important measures to ensure the growth and development of longan trees and stable production. It is also a powerful measure to increase soil fertility and improve soil mass structure. Practice has proved that reasonable fertilization can make longan plants grow robustly, promote flower bud differentiation, reduce flower and fruit drop. And improve yield and fruit quality. At the same time, reduce the magnitude of small and large fruit, enhance the tree’s resistance to adverse conditions, and extend the number of years of fruit and life.
A、The principle of reasonable fertilization of longan
The so-called reasonable fertilization is to be based on different varieties of longan, different tree age period of the annual cycle of the nutritional characteristics of the tree. Soil fertility and fertilizer supply status. At the same time, apply the principle of mineral nutrition of fruit trees, choose the appropriate fertilizer and determine the appropriate amount of fertilizer. Master the appropriate fertilization period and use the correct fertilization method.
Three major principles should be followed for reasonable fertilization.
First, according to the different varieties, the age of the tree period, the demand for various nutrients characteristics of fertilization. For example, young longan trees need more nitrogen, while adult fruit-bearing trees should be prevented from applying nitrogen fertilizer, and increase the application of phosphorus and potassium fertilizer.
Second, the annual cycle should be based on the seasonal changes in the nutritional needs of longan trees in different phenological periods. Fertilizer should be applied at the right time and in the right amount.
Third, fertilization should be based on soil type, climate conditions, fertilizer form, soil management and the fertilizer absorption characteristics of the longan tree itself. Therefore, scientific fertilization should consider both the economic and reasonable amount of fertilization. At the same time, the most suitable fertilization period and the best fertilization method should be considered.
B、The fertilization of young longan trees
Fertilization of young longan trees is to meet the plant’s nutritional growth and rapid expansion of the crown, cultivating the crown fruit area for the purpose. Fertilization period mainly revolves around several times of tapping and root development period. Generally adopt a small number of times, thin fertilizer diligent application method, the application of good to promote the tip of the strong tip fertilizer.
Just planted longan tree 1st new tips before maturity is generally not fertilized. To its ripe heart, you can start fertilizing. After that, every 2-3 months to apply 1 time. Depending on the period of root activity of young longan trees, about 4-6 times throughout the year. Initially, a thin fertilizer can be applied, using dilute human manure and urine is best. Use 30%-50% rotted human manure and urine to splash between the roots. Dilute urea solution can also be used, with 20-25g of urea per plant.
Later, as the plant grows, gradually increase the concentration and amount of fertilizer. The number of times you apply fertilizer can be reduced, grasp in each new tip just turned green, the next new root growth peak before the application. To ensure that the new roots have sufficient fertilizer can be absorbed, to lay the foundation for the next new growth.
The type of fertilizer to be applied should be adjusted with the growth of the plant and the needs of different material periods. Fertilizer to rotten human urine, urea, potassium chloride, calcium magnesium phosphate fertilizer and other rotating combined use. When the tree height 1.5-2.0m, crown width 2-2.5m, to apply less nitrogen fertilizer, and increase the application of phosphorus, potassium fertilizer. The ratio of nitrogen, phosphorus and potassium is 1:2:3. The spring tip is the basis for the growth of the next tips. Spring tip sprouting before the application of 1 organic fertilizer as a base fertilizer, and appropriate to increase the amount of fertilizer.
In the autumn before the sprouting of nitrogen fertilizer, nitrogen fertilizer to reduce the longan tree to improve the winter cold resistance. 2-3 year old young trees in September-October can be combined with the expansion of the hole to change the soil, additional organic fertilizer and green manure pressure green, and according to the soil conditions, the application of an appropriate amount of lime.
In addition, in each new shoot period when the leaves are not mature. Combined with pest control for several foliar fertilization, with a higher purity of imported urea and compound fertilizer. Properly add pure high potassium dihydrogen phosphate, spraying concentration of 0.2%-0.3%. Which is conducive to the rapid growth of young longan trees.
C、The adult longan tree fertilization
1、Fertilization at the right time
Adult longan tree fertilization is to improve yield and fruit quality, restore tree potential, reduce the magnitude of small and large fruit. And extend the fruiting period for the purpose. To be based on the age of the tree, tree potential, target yield, according to the nutrient requirements of the material period. Focus on the cultivation of excellent fruit-bearing mother branches and promote flower bud differentiation. Fertilize at the right time with the goal of preserving flowers and strong fruits.
Longan belongs to the year flower bud differentiation. The fruit tree of the same year flowering and fruit type, its fertilizer needs of the period related to the material period. Longan in February spring buds began to sprout, the inflorescence of the original base formation, after the inflorescence differentiation, flowering organ formation, followed by flowering, fruit growth and development. Long nurture fertilization period combined with the material Hou, the whole year mainly divided into three periods: pre-flowering fertilizer, young fruit fertilizer and fruit picking fertilizer.
Longan pre-flowering fertilization is to promote the differentiation of flower buds, flower spike development. Improve the quality, reduce flowering, supplement the late flowering tree nutrient deficit. Increase the fruit and promote early summer tip, to provide the nutritional basis for strong fruit and promote the tip. This is the most critical period of fertilization for the whole year. The amount of fertilizer applied should account for more than 50% of the year. Nitrogen fertilizer is the main, phosphorus, potassium fertilizer with. The ratio of nitrogen, phosphorus and potassium is 1:0.16:0.54. Half of the organic fertilizer and half of the chemical fertilizer. At present, the more used compound fertilizer in the market comes from Nagric.
3、Young fruit fertilizer
Young fruit fertilizer can supplement the longan tree flowering when the nutrients consumed. At the same time also promote fruit expansion, to prevent fruit drop. It can also promote the growth of thick summer tips. To improve yields and reduce the phenomenon of small and large annual fruit has a good role. The amount of fertilizer applied during this period accounts for about 20% of the year, mainly phosphorus, potassium fertilizer, nitrogen fertilizer with. Fertilization time can be after the first physiological fruit drop after the flowers, in early and mid-June, when the young fruit soybean size. According to the longan tree potential and the amount of fruit, appropriate fertilization once. In the rapid growth period, fertilize once in mid-July. The amount of fertilizer is 1.5-2kg of compound fertilizer. 1.5-2kg of potassium chloride and 0.5kg of urea for every 50kg of longan fruit produced.
4、Fruit picking fertilizer
We generally divide the fruit picking fertilizer into two types: pre-harvest fertilizer and post-harvest fertilizer.
① Pre-harvest fertilizer
The purpose of fertilization is to promote late fruit growth and post-harvest tree recovery. Promote the last autumn tips can be on time in about mid-September, November in the middle and late maturity. This period is also very important to fertilize. This is because the autumn tips are the mother technology of the following year’s results. And the autumn tips are related to the next year’s yield. People generally focus on pre-harvest fertilizer according to the growth characteristics of longan. People generally apply it 10-15 days before fruit picking, the application amount accounts for 30% of the whole year, mainly fast-acting nitrogen fertilizer, with phosphorus and potassium fertilizer. According to the production of 50kg of fruit to apply urea 1kg, potassium chloride 0.5kg, magnesium sulfate 0.25kg.
② Post-harvest fertilizer
For the year hanging fruit amount, weak trees, old trees, there are difficulties in the post-harvest draw. We applied effective nitrogen again after harvest to promote the development of autumn tips. In autumn drought, this period of fertilization should focus on orchard irrigation in order to receive good results.
5、Outside the root chasing fertilizer
Outside the root fertilizer is a fast and efficient supplemental fertilizer measures in longan cultivation management. At the same time is also one of the essential aspects of the longan productive and stable yield.