Detailed Explanation of Citrus Cultivation Techniques and Management Key Points
Citrus planting should be done in spring and autumn, requiring a soil layer depth of at least 80 cm or more, with 60 cm or more of topsoil; there should be necessary roads, drainage and irrigation, water storage, and ancillary building facilities; different pruning methods are needed at different stages of citrus trees; soil fertilization should be the main approach, combined with foliar fertilization, using several methods such as ring trench application, strip trench application, hole application, and broadcasting fertilizer on the soil surface.
1. Choosing a good planting time is the decisive factor in ensuring high citrus yields.
Generally speaking, citrus can be planted in both spring and autumn. Ripening periods also differ from place to place, roughly maturing in mid-September and early October of the lunar calendar. We judge based on our own local conditions.
2. Soil conditions and management are the prerequisites determining citrus growth and development.
Citrus has relatively high soil requirements. Generally speaking, too shallow a layer affects citrus root growth, so a soil layer depth of at least 80 cm or more is required, with 60 cm or more of topsoil. Citrus has strong adaptability to soil, but the most suitable soils for citrus growth are loam and sandy loam. Strongly clayey soils and overly sandy soils need improvement. Soil pH affects the availability of soil nutrients, with soil pH at 5.5-7.0; the orchard slope should be less than 25 degrees. When planning the orchard site, there should be necessary roads, drainage and irrigation, water storage, and ancillary building facilities. In specific planning, try as much as possible to concentrate into contiguous blocks and build the orchard in places with good transportation and water source conditions.
3. Citrus planting density is the key factor in ensuring citrus sugar content.
The most common spacing in citrus cultivation is 4X6 m, but there is currently a tendency to use different planting methods to make citrus grow densely in the later stage, so spacings of 4X3 m and even 4X1.5 m are also often adopted. The planting density is usually 410 plants per hectare, and under dense planting conditions there can also be 800 or even 1600 plants per hectare.
4. Reasonable pruning can provide an important guarantee for citrus growth at different stages.
Different pruning methods are needed at different stages of citrus trees.
(1) Vegetative growth stage: On the basis of trunk heading and shaping of the seedlings, the main focus is on shaping and cultivating the canopy. In the first and second years after planting, continue to cultivate the main branches and select and retain secondary main branches, and configure side branches, so that the tree shape is compact and the branches and leaves are luxuriant. Cultivate 3 to 4 flushes of shoots each year to form the canopy as quickly as possible, and remove flower buds in time.
(2) Growth and fruiting stage: Continue to cultivate the canopy and bear an appropriate amount of fruit. Promote 2 to 3 new flushes of shoots each year, arrange the branches evenly in density, and form a compact canopy as quickly as possible. The middle and upper parts of the plant should not bear fruit or bear little fruit, and pruning is mainly by bud removal and shoot control.
(3) Full fruiting stage: Tree height is generally controlled below 250 cm, the canopy is open, the outer periphery is uneven, branch growth is robust, the green leaf layer thickness should be more than 100 cm, with ventilation and light transmission, and three-dimensional fruiting. Control crossing between rows, with canopy coverage of 75% to 85%. Pruning should be adapted to the tree: remove dense branches and keep sparse ones, remove weak ones and keep strong ones; prune the upper and keep the lower, prune the outer and keep the inner; prune heavily for trees with many flowers and lightly for trees with few flowers.
(4) Aging stage: Carry out retraction pruning, using renewal or thinning of old fruiting branch groups, forcing out new fruiting branch groups in the inner canopy or lower part, maintaining sprouts, removing dense ones and keeping sparse ones, arranging them evenly, pruning more for many flowers, and appropriately pruning heavily for weak trees.
5. Fertilizer and water are the key to ensuring the citrus fruit ripening stage.
Generally, our fertilization principles for citrus fertilizer and water management are: fully meet the needs of blood oranges for various nutrient elements, advocate applying more organic fertilizer, and rationally apply inorganic fertilizers and formula fertilizers. And guide fertilization according to leaf analysis results, orchard soil analysis results, blood orange phenological periods, and so on. Our commonly used fertilization methods are: soil fertilization as the main approach, combined with foliar fertilization. Use several methods such as ring trench application, strip trench application, hole application, and broadcasting fertilizer on the soil surface. We can decide according to our own actual conditions.
6. Prevention and control of citrus pests and diseases
Several common citrus diseases: huanglongbing, canker, and scab. Citrus huanglongbing is a devastating disease. Once it occurs, it cannot be cured, and the tree must be cut down and removed in time, and slaked lime powder should be spread in the diseased hole for disinfection. Citrus huanglongbing spreads the virus through psyllids. During citrus growth, timely use of thiamethoxam, or acetamiprid, or pymetrozine, or nitenpyram, or imidacloprid, or veratrine, or fenoxycarb, or buprofezin, carbosulfan, etc. plus bifenthrin to control psyllids can reduce the incidence of the disease.