Northern Anhui is suitable for planting navel oranges. Navel oranges are fruit trees with strong shade tolerance, but sunshine is closely related to the high quality and high yield of navel oranges. Insufficient sunshine results in poor growth results and fruit coloration of navel oranges. The average annual sunshine hours in southern Jiangxi are 1340 to 1840 hours, and most counties (cities) are around 1550 hours, which can meet the requirements of navel oranges.
1. High-standard garden construction
1.1 Selection of garden sites Navel oranges are not cold-tolerant, and -6.5°C can easily cause frost damage. Therefore, according to the climate of our county, it is best to choose areas with an altitude below 700m and not choose plots where cold air is deposited in valleys for planting to prevent freezing damage caused by low temperatures in winter, leading to failure of cultivation or low economic benefits; it is also necessary to choose a location with convenient transportation , build gardens where the soil layer is thicker (at least 1m); in addition, in order to effectively reduce the occurrence of canker disease, hillside areas with surrounding forest cover should be selected to form a ready-made natural protective forest and reduce wind speed. .
1.2 Reasonable construction of terraces. According to the slope of the garden, the terraced terraces should be 3.5 to 4m wide. To prevent soil erosion, the terraces should be high on the outside and low on the inside. Drainage ditches should be opened inside the terraces; in addition, When reclaiming land, pay attention to placing the topsoil on the slopes on the surface of the garden as much as possible, so that the soil fertility in the early stages of garden construction will be higher and the seedlings will grow faster.
1.3 Improve the quality of planting. In order to enable the seedlings to grow quickly after planting and form a crown quickly, it is conducive to early fruiting and high yield. Large seedlings, large holes, and large amounts of fertilizer should be used for planting, that is, large seedlings with well-developed root systems, vigorous plant growth, and many branches should be used for planting. The planting hole should be 1 cubic meter in size, or a large trench should be dug, and organic fertilizer should be applied in layers and the soil should be plowed deeply. The density of planting should be based on the actual situation. Generally, the specifications of 3m×3m can be used, and 70 to 80 plants can be planted per 667 square meters.
2. Strengthen soil, fertilizer and water management
2.1 Soil management
2.1.1 Hole expansion and soil improvement: This work should be completed within 3 years after planting Focus on work. In the second year after planting, we begin to expand the hole and improve the soil, and then proceed year by year. We expand the hole outward year by year from the outside of the planting hole or trench, and apply organic fertilizers such as straw, garbage, farmyard manure, etc. in layers to increase the organic matter content of the soil. , continuously enhance soil fertility and lay the foundation for stable and high yields of navel oranges. In addition, since the soil in mountainous areas is highly acidic, be careful to add quicklime when expanding holes and improving soil.
2.1.2 Soil tillage: Mainly when the plants enter the fruiting period, in order to prevent soil compaction and poor root growth, the orchard soil is deeply plowed for 20 days in conjunction with the application of fruit fertilizer every winter. ~30cm. When deep plowing, attention should be paid to people facing inward and proceeding from the outside to the inside of the terraces, so that the soil after deep plowing will be higher on the outside and lower on the inside to prevent water and soil erosion.
2.2 Fertilizer management Fertilizer should be applied according to the different tree ages and different growth periods of navel orange growth. Before the plant bears fruit, the main purpose is to promote the rapid formation of the canopy as early as possible. Therefore, nitrogen fertilizer should be used as the main fertilizer. It is generally applied before each new shoot grows. Generally, 0.5 to 1kg of ammonia bicarbonate can be applied to each plant (mainly used in spring). ) or 0.2~0.3kg of urea or 0.5kg of compound fertilizer; first-fruiting trees after entering fruiting are generally fertilized 4 times a year, namely pre-flowering fertilizer, fruit-stabilizing fertilizer, fruit-strengthening fertilizer and fruit-picking fertilizer. Generally, 1kg of ammonia bicarbonate can be applied as pre-flowering fertilizer; as fruit stabilizing fertilizer, 0.5kg of ammonia bicarbonate and 0.5kg of calcium magnesium phosphate fertilizer can be applied to each plant. The application of fruit-picking fertilizer should be flexibly determined according to the amount of fruit and the vigor of the plant. , if the plant has strong vigor and few fruits, less or no fertilizer should be applied to prevent the occurrence of a large number of summer shoots. This will not only increase the workload of eradicating summer shoots, but also greatly affect the fruit setting rate; fruit-strengthening fertilizers generally need It should be applied in two times. The first application can be arranged in late July (before the autumn shoots sprout). The fertilizer can be 0.5~1kg of compound fertilizer and 0.25~0.5kg of urea. Fruit-picking fertilizer is generally arranged after picking the fruit and before winter. , applied in combination with deep plowing in winter. If the fruit yield is large, it can also be applied in two times, that is, a quick-acting fertilizer is applied immediately after picking the fruit to restore the tree vigor. The fertilizer used for picking fruit is mainly organic fertilizer. , combined with an appropriate amount of quick-acting fertilizer (mainly phosphate fertilizer), the application amount accounts for 50% of the year. In addition, oranges have a large demand for magnesium fertilizer. When applying fruit-stabilizing fertilizer or fruit-strengthening fertilizer for the first time, be sure to add 0.25kg of magnesium sulfate to each plant to meet their demand for magnesium fertilizer.
2.3 Water management Proper irrigation is also an important measure for high yield of Newhall navel oranges. Generally, the relative water holding capacity of citrus orchard soil should be maintained between 65% and 75%, that is, the soil should be kept relatively moist. In spring and summer, when there is more rain, it is necessary to clean the terraced drainage ditches to ensure that there is no accumulation of water in the citrus orchards; in autumn, there is generally less rain, especially from October to November, which is the period of rapid fruit expansion, so irrigation must be strengthened. To help the fruit expand. In addition, attention should be paid to preventing fruit cracking caused by prolonged drought and rain.
3. Reasonable shaping and pruning
3.1 The sapling stage mainly focuses on cultivating the crown. Pruning should be light, leaving more branches and leaves, and retaining the base auxiliary branches. Leave 2 or 3 main branches on the main trunk, leave 2 or 3 secondary main branches on each main branch, leave 2 to 3 new shoots on the strong peripheral branches, wipe out the rest, and leave 8 to 10 leaves on the remaining new shoots. Topping in time.
Promote early maturity, promote the germination of the next new shoot, and ensure three shoot shoots per year to achieve the purpose of cultivating a strong skeleton, increasing the number of branches, and quickly forming a high-yielding crown.
3.2 During the early fruiting period, the fruit-bearing mother branches of early-fruiting trees have the highest fruit setting rate with moderate branch lengths of 10 to 15 cm. However, early-fruiting trees are mainly due to strong vegetative growth and are more difficult to transition to reproduction. growth, often resulting in low fruit setting rate. Therefore, its growth should be controlled through intensive pruning in cultivation. First of all, part of the chopped tips should be wiped off during budding, and about 15cm should be left for topping or short cutting of the vigorous spring tips (usually about 10 leaves), which can effectively control the tree vigor and improve the fruit setting rate; secondly, in summer Work should be done to wipe out summer shoots; in addition, methods such as girdling, girdling, branch bending, and twisting can also be used for early-fruiting trees that have grown too vigorously, or can be combined with hole expansion. Around October 1, there are The purpose is to injure some more roots, and allow the injured roots to be exposed for 3 to 5 days before returning to the soil. This will help reduce the growth potential and promote the formation of strong mother branches with moderate fruiting.
4. Preserve flowers and fruits
The fruit setting rate of navel oranges is low, so preserving flowers and fruits to increase the fruit setting rate is also an important step for early and high yield of navel oranges.
4.1 Ensure the supply of nutrients: In addition to strengthening fertilizer management to enhance tree vigor, thin out weak branches, inferior flowers, deformed flowers, etc. before flowering to reduce nutrient consumption caused by useless flowers blooming; in addition, in flower buds In the early and young fruit stages, use 0.3% potassium dihydrogen phosphate + 0.3% urea + 0.2% borax, and perform extra-root top dressing 2 to 3 times to enhance nutrition, improve flower quality, and enhance pollination and fertilization capabilities.
4.2 Spray plant growth regulators: anti-dropping agents, 2,4-D gibberellins, etc. can be used to spray them during the flowering period and before the first and second physiological fruit drop. Anti-dropping agents are generally used 16～30mg/kg is used, 2,4-D is generally used 8～10mg/kg, and gibberellin is generally used 40～50mg/kg. The number and concentration of spraying should be determined flexibly according to the amount of flowers, tree vigor and different periods. If the amount of flowers is average or there are few flowers, you can spray more; if you have more flowers, you can spray less; if the tree is strong, spray more, and if the tree is weak, spray less; the concentration should be lower in the early stage and higher in the later stage. In addition, it can be combined with external top dressing when spraying.
5. Strengthen the prevention and control of pests and diseases
Navel oranges are prone to pests and diseases. Controlling pests and diseases is also an important part of ensuring high yields and high quality. For Newhall navel oranges, which are first-fruiting trees, the main disease is to prevent and control canker. In addition to choosing a garden with a protective forest for cultivation, the key to its prevention and treatment is to use preventive medicine when the leaves change color and the fruit grows to the size of a glutinous rice ball. period; in addition, during the fruit growth period, pay attention to timely medication and prevention after strong winds or typhoons to prevent the prevalence of ulcers caused by multiple wounds after typhoons.