A Complete Analysis of the Key Points of High-Yield Citrus Cultivation Techniques
There are records of citrus cultivation in China as far back as very early times, and China is also a major citrus-producing country in the world. Even so, the amount of citrus consumed in China each year is also astonishing. Therefore, increasing citrus yield is the topic that every grower cares about most. To achieve high citrus yield, the cultivation techniques are closely related to it.
High-Yield Citrus Cultivation Techniques
1. Digging planting holes: On sandy soil at an altitude of 300 to 500 m with loose, fertile, deep soil and a pH value of 6 to 7, turn over and sun-dry the soil before the ground freezes so that it fully weathers, then dig pits. The pits are 0.8 m wide and 0.7 m deep, and the surrounding drainage ditches should be deep. Dig the holes at a planting spacing of 1.5 to 2 m between plants and 2 to 2.5 m between rows, apply more than 10 kg of fully decomposed organic fertilizer per hole, mix thoroughly, and then cover with soil.
2. Planting seedlings: Select robust seedling stock for transplanting with soil attached to the roots. Plant the seedlings upright in the center of the planting hole, firm the soil around them, then cover with 3 to 5 cm of soil, at about 60 to 80 plants per mu, and water thoroughly with rooting water in time.
Methods of Applying Winter Fertilizer to Citrus
In general, winter fertilizer can be applied by two methods: first, radial trench fertilization. According to the size of the tree canopy and along the direction of horizontal root growth, open 4-6 radial trenches, shallower near the trunk at the bottom and deeper toward the extension of the canopy projection. With this method, the fertilizer is distributed over a wider area, and the fertilization position can be alternated every other year, expanding the fertilization area and promoting root absorption. It is especially suitable for mature citrus orchards. Second, dig an arc-shaped or ring-shaped deep trench along the outer edge of the canopy, with a depth of about 50 cm; the trench width depends on the amount of fertilizer. When digging the trench, the topsoil and subsoil should be piled separately. Apply decomposed organic fertilizer or micro-element fertilizer to the lower layer, and nitrogen chemical fertilizer to the upper layer. When filling the trench, first fill in the more fertile topsoil, and put the subsoil on the surface.
How to Protect Citrus Flowers and Fruits
1. Use Guangzengsu 802 to protect flowers and fruits. Spraying Guangzengsu 802 on the leaves can improve leaf function, thicken the leaves, increase chlorophyll content, promote canopy growth, and enhance the tree's own disease resistance. It has a remarkable effect on protecting flowers and fruits and increasing the fruit-setting rate, opening a new pathway for high and stable citrus yields and improved fruit quality. Spray Guangzengsu 802 2-3 times each during the initial flowering stage and the fruit-setting stage of citrus, with every 10 g of Guangzengsu 802 diluted in 20 kg of water for foliar spraying.
2. Foliar fertilizer spraying to protect flowers and fruits. In spring, citrus is in the stage of sprouting, flowering, vigorous division of young fruit cells, and alternation of new and old leaves, which consumes a large amount of stored nutrients. At the same time, the soil temperature is generally relatively low, and root absorption capacity is relatively poor, especially for orange trees with a large number of flowers and poor tree vigor; foliar fertilizer spraying has a good effect on protecting flowers and fruits.
3. Use rare earth to protect flowers and fruits. According to experiments, spraying rare earth solution to protect flowers and fruits is best done 3 times: at the flower bud swelling stage, the early bud stage, and the beginning of young fruit enlargement, increasing the fruit-setting rate by 38.1% and the yield by 27.9%. In production practice, the first spraying is generally done from flower bud swelling to the early bud stage, and the second spraying is done at the beginning of young fruit enlargement after the second physiological fruit drop, generally using a rare earth solution at a concentration of 300 mg/kg.
Basic Methods of Citrus Shaping and Pruning
1. Heading back: Cutting back 1/3 to 1/4 of the length of a branch is called light heading back; cutting back 1/2 is moderate heading back; cutting back 2/3 to 3/4 is heavy heading back. Heavy heading back removes the plump buds with apical dominance, and fewer new shoots sprout from the remaining part, so the growth vigor is stronger and the branching rate is also stronger. Moderate heading back leaves more plump buds, the number of sprouting new shoots is medium, and the growth vigor and branching rate are also medium. Light heading back produces more new shoots, but the shoot growth amount and growth vigor are weaker. In shaping and pruning, different degrees of heading back should be used according to the requirements of the tree form for the number and position of scaffold branches and the actual growth conditions of young trees.
2. Thinning: Completely removing 1-2-year-old branches from the base is called thinning. Thinning is mostly used to remove excessive dense and weak branches, clustered branches, diseased and insect-damaged branches, and water sprouts, improving light and nutrient distribution for the retained branches and shoots, making them grow robustly and bear flowers and fruits, which benefits the tree's reproductive growth and leads to early fruiting and early high yield.
3. Pinching: Before new shoots stop growing, according to the length required for shaping, removing the tip portion of the new shoot and retaining the needed length is called pinching. Its effect is similar to heading back. Pinching can limit the elongation growth of new shoots, promote thickening growth, and make the shoot tissue solid. After pinching, once the tip buds of the new shoot mature, they also have apical dominance, can produce robust branches, and lower their branching height, achieving the shaping requirements.
4. Notching: It can be used to supplement main branches when shaping young trees. When a main branch is missing in a vacant part of the canopy, before spring sprouting, select a bud at an appropriate position on the trunk and make a horizontal cut above the bud deep to the xylem. This has the effect of promoting latent bud sprouting or promoting stronger shoot growth, causing new shoots to emerge or weak branches to become stronger, so as to meet the requirement of cultivating main branches.
5. Branch bending: During the shaping period of young trees, methods such as pulling branches with ropes, propping branches with bamboo sticks, and hanging branches with heavy objects such as stones can be used to change the growth direction of the main and side branches of the plant, so as to meet the shaping requirements for azimuth angles and the angle between large branches, thereby regulating the distribution and growth vigor of scaffold branches. This is a commonly used and effective technical measure when shaping young citrus trees and cultivating scaffold branches such as main and side branches.
To achieve high citrus yield, both early-stage cultivation and later-stage management must be done well; neither can be omitted. If there is a problem in any one of these links, it will have a great impact on the yield. Branches must also be pruned timely every year, as only then will the fruit-setting rate increase and the growth be better.