How to Manage Young Citrus Trees? A Detailed Guide to Key Practical Techniques
Citrus is a very common fruit for us, sweet and delicious, with thick flesh and plenty of juice, and it is also highly nutritious, containing rich vitamins and nutrients, deeply loved by consumers. Growing citrus has also become a very popular planting project, so how should young citrus trees be planted and managed?
Management Techniques for Young Citrus Trees
1. After planting, the seedlings should be watered frequently to keep the soil moist and encourage new roots to grow. Only 15d after planting can the seedlings gradually survive. Before the seedlings survive, only watering is suitable, and fertilizing is not suitable.
2. Cover the tree base of the fruit tree. Cover the tree base with rice straw, crop stalks, green manure or plastic film, with a covering thickness of 10-15cm and 10cm away from the trunk. This helps keep the soil loose and moist and promotes the sprouting and growth of branches and shoots.
3. After the first batch of buds on the seedlings sprout, only then may diluted decomposed human manure and urine be applied, or decomposed bran water, or biogas slurry, or water-soluble fertilizer. Generally, from the sprouting of the first batch of buds on the seedlings until the shoots mature, do not drench with commercial chemical fertilizers to avoid fertilizer damage.
4. Remove flower buds sprouting on young trees in time to prevent flowering from consuming excessive nutrients, but for flower buds with leaves, only the flower buds must be removed while the leaves are retained.
Shaping and Pruning of Citrus
The biological characteristics of citrus fruit trees are one of the important bases for shaping. The correlation between branch and leaf growth and root growth, apical dominance, branching angle, and self-pruning of terminal buds are important conditions determining pruning. The characteristics of young trees are strong growth vigor, mainly by producing shoots to expand the canopy, cultivate framework branches, and increase canopy shoots and leaves, so appropriate pruning should be carried out on the basis of shaping.
1. Line-pulling shaping
Some seedlings have main branches leaning to one side, some seedlings have central main branches growing upright with excessively strong vigor, and some seedlings have branching angles that are too large or too small. These seedlings need to be pulled apart and corrected with hemp string so that the main branches are evenly distributed, with the main branches forming 40°~50° with the extension line of the trunk.
2. Suppress the strong and support the weak
Two or three days after shoot emergence, inspect the whole orchard and remove the particularly vigorous and prominent tender shoots. For canopies that are uneven in height, shoots at overly high positions should be removed once or twice so that the new shoots below grow longer. Strong branches should be delayed by 4-7d in shoot emergence, and the new shoots will be relatively more numerous and shorter. Through correction during several new shoot periods, the shortcoming of unbalanced canopy development will gradually be corrected.
Fertilization Methods for Citrus
Methods such as ring trench application and strip trench application may be used. Farmyard manure used must be fully fermented and decomposed; a one-time application of chemical fertilizer should not be excessive, and it should be applied lightly and frequently. In addition, the main root layer of adult trees is distributed at a soil depth of 40-60cm, and their main absorbing roots are the root tips of fibrous roots——the new root portion. This should be used as the basis when determining fertilization depth and location.
Carry this out in November-December. The specific method is to apply once every other year, alternating between plants, digging radial, semi-ring or ring fertilization trenches outward from the drip line of the canopy. When digging, be careful not to cut off large roots. The amount of fertilizer applied should be increased or decreased according to tree age and growth vigor. Combined with root pruning, place weeds and green manure at the bottom layer of the trench for each plant, then apply base fertilizer and mix it thoroughly with part of the soil in the fertilization trench. Fruiting trees should be given additional potassium fertilizers such as plant ash and potassium sulfate to facilitate flowering and fruiting.
Control of Common Pests and Diseases
1. Control of scab: Spray before the new buds of spring shoots sprout until the buds are 2 millimeters long and when 2/3 of the flowers have fallen. Choose 80% mancozeb 800-fold solution or 75% chlorothalonil 500-600-fold solution, and apply once more after 10-15 days. Before and during the disease period, use Dacotech mancozeb 800-fold solution once every 7 days, spraying 2 times consecutively.
2. Control of anthracnose: ① Strengthen cultivation management, provide the tree with sufficient fertilizer and water, prevent waterlogging, prevent soil compaction, prune in time, renew and rejuvenate, and strengthen the tree. ② Spray appropriate chemicals. Agents that inhibit pathogen development and conidia include 50% carbendazim 800-fold solution, 70% thiophanate-methyl 800-fold solution, 50% amobam 800-fold solution, and 65% zineb 500-fold solution, which can also control diseases such as scab.
3. Control of gummosis: ① Strengthen cultivation management, maintain drainage ditches well, improve heavy clay soil, practice reasonable intercropping, prune and thin in time, keep the orchard ventilated and light-transmitting, reduce orchard humidity, apply more organic fertilizer, and balance fertilization, with nitrogen, phosphorus and potassium roughly at 1:0.3-0.5:1-1.2; at the same time apply boron fertilizer, which helps control the occurrence of this disease. Borax at 500-800 times may be sprayed frequently or boron fertilizer applied to the soil. Pay attention to drainage during the rainy season, whitewash the trunk, and thoroughly control jewel beetles and longhorn beetles, which can effectively reduce the occurrence of this disease. During the peak occurrence period of jewel beetles (April-May), spray once every 10 days for 2-3 consecutive sprays. Options include 40% dimethoate 1000-fold solution or 80% dichlorvos 1000-fold solution, etc. ② Chemical control. On the diseased part, use shallow scraping and deep cutting, making several cracks reaching the xylem (at intervals of about 1 centimeter), then apply 90% fosetyl-aluminum 100-fold solution or 843 rehabilitation agent stock solution, or thiophanate-methyl 100-200 times, duoxymycin 500-600ppm plus 2,4-D 20ppm, etc.
4. Mites: mainly red spider mites and yellow spider mites. They can occur 12-20 generations a year, with 2 peak generations. The first damages spring shoots in April-May, and the second damages autumn shoots in September-October (in some areas). When the temperature is higher than 35℃ or lower than 12℃, the mite population decreases sharply. When red spider mites damage severely, the leaves become grayish white and lose their luster; yellow spider mites cause raised yellow spots on the upper surface of leaves, which then become distorted and deformed. Both cause leaf and fruit drop, seriously affecting tree vigor and yield.
As mentioned above, compared with other fruit trees, citrus has very strong vitality and is relatively simple to manage. With good pest and disease control measures, fertilization, and pruning, the annual citrus yield is very astonishing. From this point of view, the prospects and returns of growing citrus are very considerable.