Detailed Explanation of Key Points of Scientific Citrus Planting Techniques

Citrus has a very long planting history in our country, and its yield can rival that of apples. The vitamin C content of citrus is outstanding among fruits, even higher than that of apples, so our country is a major consumer of citrus. With such a high consumption volume, good cultivation techniques are needed to grow high-yielding citrus in order to meet people's needs.

Scientific Citrus Planting Techniques

1. In the early stage, citrus orchards should implement planned dense planting, with 3 to 4 times the conventional density, to achieve early fruiting and high yield. Conventional planting density is generally appropriate at a spacing of 3 x 3.5 m (63 trees/mu) or 3 x 3 m (76 trees/mu).

2. Planting time. Spring planting is preferable, generally from early March to early April, before the citrus buds sprout.

3. Cultivation method. Small seedlings can be planted in planting trenches or planting holes, with the trench or hole depth at about 0.8 m. The lower layer of the planting trench or hole should be filled layer by layer with a sufficient amount of decomposed organic fertilizer or superphosphate. Generally, apply 30-40 kg of organic fertilizer plus 1-1.5 kg of phosphate fertilizer per hole. For transplanting trees to be thinned out, plant them on raised beds as a base, raising the planting height and expanding the root system.

Main Measures for Citrus Cultivation Management

1. Thin out and interplant trees, maintain necessary canopy spacing, and thin out or remove interplanted trees on the principle of not affecting, or affecting as little as possible, the retained trees. The sign that thinning is needed is when orchard yield begins to decline and canopies cross and shade each other. Taking the natural shape of Satsuma mandarin as an example, when canopy coverage reaches more than 84%, canopy overlap reaches more than 500px, and the leaf area index reaches more than 7, preparations for thinning should begin; when canopy coverage reaches 100%, thinning is immediately needed. Generally, 4-5 years before thinning or removal, begin gradually compressing the interplanted trees, and carry out thinning when their canopy is less than 1/2 that of the permanent trees and their yield is less than 1/3 that of the permanent trees.

2. For trees to be thinned and transplanted, in March-April of the year before transplanting, or at the latest in September-October, perform ring trench root pruning. The method is: first take the trunk circumference as the radius and the trunk as the center to make a circle, then dig down along the circumference to fully cut its roots. After cutting the thick roots, trim the cut surfaces smooth, then fill the ring trench with fertile soil and organic matter to promote the growth of fine roots. In this way, by the time of digging and removal the following year, the root system of the remaining trees will be less affected, and the survival rate and growth vigor of the transplanted trees will be improved. For ease of operation, during thinning it is generally preferable to first remove all interplanted trees between rows, but where operating conditions permit or where trees within rows are relatively dense, interplanted trees within rows may also be thinned first, so as to fully utilize space and increase yield.

Citrus Fertilizer and Water Management

Citrus requires a relatively large amount of fertilizer. Large trees in full fruit stage should be fertilized 3-4 times each year. One is post-harvest fertilizer, applied as base fertilizer from October to November. Apply 50 kg of organic fertilizer plus 1 kg of toosendanin biological compound fertilizer in pits. For mid-season varieties harvested relatively late, it can be applied one week before harvest. The fertilization amount accounts for 40%-50% of the annual fertilizer use. One is bud-promoting fertilizer, applied 1-2 weeks before citrus sprouting when the weather turns warm in spring, to promote neat spring shoot emergence, robust growth, delay old leaf abscission, and increase fruit set rate. Apply 1 kg of nitrogen fertilizer plus 1 kg of toosendanin biological compound fertilizer per tree. Another is fruit-strengthening fertilizer, applied in July after physiological fruit drop stops. Apply 0.5 kg of potassium fertilizer plus 1 kg of toosendanin biological compound fertilizer per tree; for young trees, it can be applied together with shoot-promoting fertilizer and irrigation.

Common Citrus Diseases and Control Methods

1. Citrus anthracnose: often starts from the leaf tip, initially dark green, like the appearance of being scalded by hot water, with no obvious boundary between diseased and healthy parts, then turns pale yellow or yellow-brown, and the leaves curl and fall off. For chemical control, spray once each during the tender shoot stages of spring, summer, and autumn shoots. To protect young fruit, it should be done within one month after flower drop, spraying once about every 10 days, for 2-3 consecutive sprays. It can be sprayed with 1000-fold solution of Juncheng or Guoyou 101 fungicide + 1000-fold solution of Penchaike.

2. Citrus scab: mainly damages new shoots, leaves, and young fruit, and can also damage calyx and petals. Control method: the first time when spring buds sprout, the second time when 2/3 of the flowers have faded. It can be sprayed with 1000-fold solution of Juncheng or Guoyou 101 fungicide + 100-fold solution of Penchaike.

3. Citrus foot rot: mainly damages the citrus root crown about 10 cm above and below the soil surface. When diseased trees are found, promptly scrape off the rotted part and some healthy tissue around the diseased area, then apply 1000-fold solution of Junxianwei or use 3500-fold solution of Junxianwei to irrigate the roots, applying 1000 ml of medicinal solution per tree.

Scientific planting of citrus will greatly increase the per-mu yield of citrus, thereby creating better economic benefits. Citrus cultivation requires good preliminary management work. Site selection and seedling selection are relatively important. Do not choose places with standing water, and the drainage system must be adequate. Later pest and disease control must be strengthened. Only in this way can excellent citrus be cultivated.