Citrus Cultivation Techniques: Temperature, Soil, and Fertilizer Are Key Factors Affecting Yield
China is a major cultivation area for citrus, with a long history of growing it. There are many citrus varieties, and among the more famous is Changde Shimen citrus, which is large and juicy and deeply loved by people. The growing environment of citrus is affected by many factors, such as temperature, soil, and fertilizer. Below, let us learn together about high-yield citrus cultivation techniques.
I. Planting Techniques
1. Soil improvement
Before planting on dry land, it is advisable to dig trenches or large holes to improve the soil. Trenches should be 1.0-1.5 m wide and 0.8-1.0 m deep; or large holes should be 1.0-1.5 m in diameter and 0.8-1.0 m deep. For paddy fields or waterlogged land, in addition to digging trenches or large holes to improve the soil, also dig deep drainage ditches to lower the groundwater level to below 1 m. For each cubic meter of trench or hole, fill in 30-50 kg of crop straw, farmyard manure, weeds, etc., and mix evenly with the soil or backfill in layers. For soil deficient in mineral nutrients such as phosphorus, magnesium, and calcium, add an appropriate amount of the corresponding mineral fertilizer when backfilling. For acidic soil, add an appropriate amount of lime when backfilling; for alkaline soil, add an appropriate amount of sulfur powder when backfilling. Plant only after the trenches and holes have been backfilled for 4-6 months.
2. Planting
After moderately pruning the root system and branches and leaves of the nursery stock, place it in the center of the planting hole, spread out the roots, hold it upright, and while filling with soil, gently lift the seedling upward and press the soil firmly so that the roots are in close contact with the soil. When planting container-grown seedlings, first take the seedling out of the container with the soil, use your hands to remove the outer layer of soil to expose part of the root system, then place it in the center of the planting hole, cultivate soil around it, hold it upright, and press firmly, with the root crown exposed 5-10 cm above the ground, and water thoroughly to settle the roots.
II. Soil, Fertilizer, and Water Management
1. Soil management
Deep plowing and hole expansion should be carried out after the autumn shoots stop growing or in combination with applying base fertilizer, starting from the edge of the original planting hole and gradually expanding outward. When backfilling, mix in green manure, straw, or decomposed human and livestock manure, compost, barnyard manure, cake fertilizer, etc.
2. Intercropping or growing grass
It is advocated to implement a grass-growing system in citrus orchards. The intercrops planted should preferably be short-stemmed, shallow-rooted legumes or forage grasses, which should be mowed at the appropriate time and turned into the soil or used as mulch over the tree disk.
3. Mulching and soil banking
In high-temperature or dry seasons, it is advocated to use straw and other materials to mulch the tree disk, keeping the mulch at least 10 cm away from the root crown. Soil banking is generally carried out in winter, and the soil should be loosened by shallow plowing before banking. Pond mud, river mud, or fertile soil near the citrus orchard may be added, with the thickness preferably not higher than the graft union.
4. Shallow plowing
Carry it out in summer, autumn, or after fruit harvest, but not during the rainy season. Conduct shallow plowing once a year or once every 2 years to keep the soil loose. The depth of shallow plowing should be ≤10 cm. Sloping land should be deeper, and flat land should be shallower. For citrus orchards with many weeds, herbicides with little environmental impact may be used in limited amounts.
5. Fertilization
It is advocated to apply more organic fertilizer, apply inorganic fertilizer rationally, and use formula fertilization and economical fertilization.
6. Training and pruning management
The purpose of training and pruning citrus is to enable the plant to form and maintain a reasonable tree structure, make full use of light energy and space, and achieve early fruiting, early high yield, stable yield, high quality, and high efficiency. It is the activity of directly pruning the tree or carrying out other similar operations. In the final analysis, training is shaping the tree form so that it forms an ideal tree structure; pruning is the technique of directly treating branches and shoots on the tree body, such as thinning, heading back, renewal pruning, pinching, bud removal to release shoots, branch bending, girdling, and root cutting, etc.
Training and pruning are interdependent and mutually complementary. To cultivate and maintain a good tree form, it must be achieved through a series of pruning treatments; and for a plant that has not undergone training, reasonable pruning is difficult to carry out. Training and pruning run through the entire life cycle of citrus, but the emphasis differs at different developmental stages. For young trees, training is the main focus; for mature trees, various pruning techniques are mainly used to maintain and adjust the tree form and regulate the contradiction between vegetative growth and reproductive growth, so as to extend the economic life of the tree.