Detailed Explanation of Orah Mandarin Planting Techniques and Management Methods
Orah mandarin is a late-maturing hybrid citrus variety, derived from a cross between "Temple" tangor and "Dancy" red mandarin. In production, sweet orange, red mandarin, trifoliate orange, or citrange can be used as rootstock, but it is graft-incompatible with trifoliate orange x grapefruit hybrid and should be avoided.
Orah Mandarin Cultivation Techniques
Orah Mandarin Seedling Preparation
When cultivating Orah mandarin, ensure the seedlings have good plant shape and complete root systems, and in particular do not carry pathogens of quarantine diseases such as citrus huanglongbing, canker, and tristeza. For dry slopes or alkaline soil, mainly Ziyang sweet orange, sour mandarin, or red mandarin should be used as rootstock; for paddy fields, large-leaf trifoliate orange should be used as rootstock (using trifoliate orange or citrange as rootstock easily leads to nutrient deficiency yellowing symptoms).
Orchard Soil Tillage
Choose loose, fertile, well-drained, wind-sheltered and sunny sites or paddy fields to establish the orchard. For sites with gentler slopes, a high-horsepower tractor with a single plow can be used for full-orchard deep plowing and subsoiling. Plow when soil moisture is not high, with the direction along contour lines or perpendicular to roads. One plowing can reach a depth of 60-70 cm, then harrow once or twice until level. Then according to the drainage conditions of the slope, flat land, or paddy field, use an excavator to dig drainage ditches. Alternatively, a large excavator can be used for full-orchard deep digging of 60 cm or more at once, then leveling with a harrow. Or dig planting holes 1 m long, 1 m wide, and 0.6 m deep, place 50 kg of well-decomposed organic fertilizer and 1 kg of superphosphate, mix well with soil, and backfill, with the backfilled soil mounded above ground level.
Orah Mandarin Planting Techniques
1. Planting density: Orah mandarin planting spacing is 2-3 m between plants and 3-4 m between rows, with 56-110 plants per mu, which can be selected according to planting preferences and management level.
2. Planting time: In southern regions, the best planting time for Orah mandarin is from February to early May, when temperatures rise and there is more rainfall or cloudy weather. It can also be planted from September to November during rain or cloudy days. Container seedlings can be planted year-round.
3. Planting method: For bare-root Orah mandarin seedlings, the whole seedling can be soaked in 0.1% potassium permanganate solution for about 2 minutes, removed and air-dried for about 3 minutes, then rinsed once with clean water, which can kill pathogens on the plant surface. Then soak the root system of the Orah mandarin seedling in a solution of fungicide, insecticide, and nutrient solution for about 8 hours. After removing the seedling, dip it in yellow mud slurry made with this solution and then take it for planting.
Orah Mandarin Young Tree Management
1. Fertilizer and water management: Orah mandarin has extremely strong growth vigor and requires abundant water and fertilizer. A water-fertilizer integrated drip irrigation system should be installed as much as possible. The system mainly includes a fertilizer dissolution tank, water tank, filter, water pump, main pipe, branch pipes, switches, drip tape, and drip heads. For young trees, the goal is to rapidly build the canopy, so frequent light applications should be made with a reasonable NPK ratio. Apply organic fertilizer as base fertilizer only once per year, about 15 kg of organic fertilizer and about 2 kg of compound fertilizer per plant per year.
2. Training and pruning: Orah mandarin has extremely strong shoot-sprouting ability. Under good water and fertilizer conditions in Nanning, Guangxi, young trees can sprout new shoots 6-7 times a year. If not controlled, they often grow in clusters with short and weak branches. After planting seedlings, set the main trunk height at about 20-30 cm, then prune according to the guiding principle of the "one fork, three branches" method, that is, leave about three evenly distributed and stout branches at each fork, remove the excess, and when overlong branches mature, cut them back, keeping each branch 20-25 cm long. This method has a clear guiding principle for training, is easy to operate, and can also make the whole tree shape reasonable, with branches that are relatively stout and mature as quickly as possible, sprouting new buds, which is conducive to simplified management of Orah mandarin trees.
Orah Mandarin Mature Tree Management
1. Fertilizer and water management: This can be summarized in three phrases: "nitrogen in spring, potassium in summer, compound fertilizer in autumn; drench with bran water during the expansion period; apply heavily after harvest to promote recovery." Apply well-fermented organic fertilizer once per year at 50 kg per plant, combined with peanut bran, superphosphate, etc. From September to December during the fruit expansion period, attention should be paid to strengthening water and fertilizer irrigation during drought, with frequent light applications. From January to March during the fruit ripening period, attention should be paid to controlling water to increase sugar accumulation.
2. Training and pruning: This can be summarized in four phrases: "retain spring shoots as appropriate, cut off summer shoots, uniformly release autumn shoots, strictly control winter shoots." That is, when spring shoots grow to 5 cm long, keep 2-3 strong buds in different directions per branch. The principle for retaining buds is to thin out where dense and keep where sparse, thin out short ones and keep long ones, thin out weak ones and keep strong ones. For excessively vigorous branches, keep 6-7 leaves and pinch the tip. Cut off all summer shoots. From early August to mid-to-upper September, uniformly release autumn shoots and remove sporadic buds. For weaker trees, a small number of late autumn shoots may be retained as appropriate, and the rest and all winter shoots should be removed. Winter pruning should be based on ventilation and light penetration, reasonable branch distribution, and a compact canopy. Cut off diseased and pest-damaged branches, burn them in a centralized manner, and carry out orchard cleaning at the same time.
3. Flower and fruit management: Orah mandarin has many flowers, a high fruit-setting rate, and little late fruit drop, which easily causes insufficient nutrient supply, poor flower and fruit growth and development, small fruit, rough peel, and poor quality, and also easily causes alternate bearing. Therefore, in "on" years, attention should be paid to fruit thinning. Fruit that is too densely set can be thinned in 2 rounds, with thinning after physiological fruit drop is complete. In the second round, retain about 300 fruits. Calculated at 3 fruits per jin, 3-4 year old fruiting trees need only 40-50 kg of fruit per plant depending on tree vigor. In "off" years, attention should be paid to spraying foliar fertilizers such as monopotassium phosphate to protect flowers and fruits. In this way, a bumper harvest every year can be achieved.
4. Timely harvest: Orah mandarin can begin to be harvested in early January. Around mid-February, maturity is relatively high, and it can mainly supply the two important festivals of Spring Festival and Lantern Festival. It should be harvested before early-to-mid March, and harvesting too late is not advisable, so as not to affect flowering in the next season. Clean Orah mandarin can be stored at room temperature for more than 1 month, while unclean fruit peel surfaces are susceptible to green mold and blue mold. The main commercial processing flow of Orah mandarin includes harvesting - handling - washing - fungicide treatment - waxing - grading - labeling - boxing, etc. For fungicide treatment, imazalil at 2000 mg/kg, 45% prochloraz 2000-fold solution, etc. can be used.