From mid-April to the end of May, it is a key period for citrus from the time of thanking flowers to stabilizing fruit. It is generally called the young fruit period. In citrus production, it is usually called the fruit-preserving period--stable fruit period. Citrus has experienced two important physiological fruit drop stages after the first physiological drop and the second physiological drop, especially the cultivation management of the second physiological drop to the stable fruit, which often directly affects the result tree. Yield and fruit appearance quality. Therefore, strengthening the management of citrus young fruit period, reducing physiological fruit drop and unnecessary objective factors, and increasing the fruit setting rate are of great significance for the whole year of production.
Citrus Garden April Management Points
To this end, the author suggests that the fruit farmers should implement the following management points and precautions:
First, timely thank you flowers - stable fruit fertilizer
Citrus buds, falling flowers, etc. consume the most nitrogen in the tree, so it should be appropriate to apply nitrogen fertilizer at the flowering stage, such as high-nitrogen type fertilization, 1-2 kg / mu; for plants with less fruity and less tree-like, It is necessary to apply 2-3 kg/mu of water-soluble organic fertilizer plus NPK balanced type fertilizer to promote roots and roots. After 4-6 months of Xiehua - young fruit expansion period, it is necessary to apply potassium fertilizer, such as potassium sulfate 1-2 two strains.
Second, timely spraying of fruit fertilizer
The second physiological fruit drop (ie, fruit drop without handle) is mainly fruit malnutrition, and the embryo lacks essential nutrients during development and stops developing to cause fruit drop. The elements of demand in different stages of fruit development are different, so that it is necessary to supplement the mites, ensure the normal development of the fruit, and reduce the physiological fruit drop.
Essential organic compounds (sugars) and mineral elements in the citrus flowering stage: buds - spring compounds require organic compounds, nitrogen, boron, zinc, magnesium, etc.; Xiehua ~ young fruit formation period, requires organic compounds, phosphorus, boron, Calcium, etc., spends 32% of the total amount of phosphorus needed throughout the flowering period; the young fruit develops and expands, requiring more organic compounds, potassium, and calcium.
Third, the right amount of hormones
A well-fed tree, spraying cytokinin before the first physiological fruit drop, is conducive to reducing fruit drop; spraying gibberellin GA3 (920) or 2-4 before the second physiological fruit drop is beneficial to inhibit the formation of abscisic acid Thereby reducing the peeling of the fruit stem from the layer. Late-ripening citrus is mostly non-nuclear and less-nuclear citrus varieties, which can be used early. Spraying 20ppm of 920 (ie 4% water 100ml and 400kg) in Xiehua 2/3, spraying 25ppm at intervals of 15 days. 920 (ie 4% water 100 to water about 300 kg). Multi-core varieties or pomelo, with or without 920. During the fruit-preserving period, natural regulators such as algae, brassinolide and sodium nitrophenolate can be used to enhance the stress resistance of fruit trees, regulate the transfer of plant nutrients from branches and leaves to flowers and fruits, and avoid the fruit growth caused by excessive growth of branches and leaves. Growth is blocked.
Fourth, the appropriate ring cuts the fruit
Ring cutting is generally aimed at plants with strong tree growth and strong vegetative growth, such as sugar oranges of sour orange rootstock. Especially for the first two years of fruit-bearing plants, it is best to protect the fruit by ring cutting, because the tree's nutritional regulation ability is poor, the vegetative growth is too strong, it is difficult to protect the flowers and fruits.
Ring cutting method: half circle misalignment method and full circle ring cutting method can be used. The safety factor of the half circle misalignment method is better than the full circle loop cutting method, and it is not easy to cause the whole plant to die.
Ring cutting time: according to the amount of flowers, nutrient consumption. Plants with few flowers and few fruits have less nutrient consumption due to consumption of trees, and vegetative growth is relatively dominant. The first knife should be carried out during the full flowering period, and the second knife should be carried out at the end of the first physiological fruit drop. On the contrary, plants with more fruits should be carried out after the flowering period to the first physiological fruit drop (about 5 days after the flowering). Generally, it is treated once. If there is too much rain, look at the fruit drop for 2-3 times. In the middle and late May, if the cut tissue has healed and the tree is still prosperous, there is a tendency to take a summer shoot, which can be cut again. If the fruit has turned green in this period and there are more fruits, it is generally not suitable to carry out ring cutting. Because the small fruit turns green after normal, it needs to be supported by the fertilizer in the rhizosphere. Otherwise, after the circumcision again, the growth of young fruit may be affected.
Ring cutting position: the ring cuts up and cuts on the branches extending 1.5 meters down the top tip.
Ring cutting strength: 0-1 knife (knife No. 0 / straight hook; No. 1 knife / 1 mm) should be used, and the depth should be just xylem.
V. Pay close attention to the prevention and control of pests and diseases
Pest and disease hazards: red spiders, yellow spiders, aphids, flower buds, malignant leaf worms, anthracnose, scab, black spot, brown spot and other hazards caused by leaves and flowers.
Effective agents: acetyloxazole, snail ester, avermectin, etc. for red and yellow spiders; imidacloprid, acetamiprid, thiacloprid, etc. for aphids, thrips, chlorpyrifos, pyrethroids, etc. Anthracnose, scab, black spot, brown spot disease can be used alternately with mancozeb, propargin, thiophanate, azoxystrobin and pyraclostrobin.
Sixth, prevent abnormal weather
1. In case of dry weather, it is necessary to timely moisturize and moisturize; in the rainy weather, clean the drainage ditch inside and outside the orchard to avoid the accumulation of water after the rain affects the root growth and causes the fruit drop.
2. Abnormally hot weather. Temperatures above 34 °C in citrus young fruit will affect the growth of the fruit, especially the photosynthesis and antioxidant defense system, resulting in fruit drop. Precautionary measures: Spraying seaweed high-phosphorus foliar fertilizer before the onset of high temperature can improve stress resistance.
3. For strong typhoon, hail and other bad weather, we should do a good job in wind and air defense in time, do a good job of establishing windproof walls, covering membranes, and rationally cutting spring shoots to prevent the young fruit from being subjected to wind scratches and fruit drop.
Seven, early control of summer shoots
1. Controlling the time: When the spring shoots are ripe, the early stage of the summer shoots (early May)
2. Technical requirements: Nutritional control: After the Xiehua-spring shoots, the roots are washed with high potassium and low nitrogen and 3-5 kg/mu, 1-2 times. Foliar application: 0.3%-0.5% potassium dihydrogen phosphate 2-3 times; in the case of rain, 500-750ppm paclobutrazol can be added and sprayed once. It is recommended to use the method of promoting the rapid and old-fashioned summer shoots to reduce the fruit drop caused by the fact that the shoots are quick and mature. The ring cutting is good for controlling the summer shoots. Artificial smear. When a small amount of summer shoots appear, avoid excreting immediately. Otherwise, only more summer shoots will be induced. When the summer shoots of the tree are within 5% of the total shoots, they will grow, and some growth hormones will be consumed through the growth of summer shoots. On the one hand, it promotes the absorption of nutrients in the soil by the root system, and on the other hand, balances the vegetative growth and reproductive growth of the tree, thereby achieving the effect of suppressing a large number of summer shoots with a small amount of summer shoots.
Eight, matters needing attention
1. Ring cutting precautions
The weather during the ring cutting is better for sunny days, which helps the wound to heal; if it is rainy and rainy after the ring cutting, the wound should be applied with a fungicide to avoid infection. It is advisable to cut the branches in the third and fourth grades. Try to avoid the first and second branches. Do not cut the trunk on the trunk to avoid the whole plant from dying. For the sake of insurance, it is possible to keep the branches with less fruit and less tips. As an auxiliary measure, ring cutting is not suitable for years of use, otherwise it will easily cause premature aging of trees. After the ring cutting, it is necessary to strengthen the foliar nutrition spraying to promote the tree. If the ring is excessively cut, the wound should be disinfected with a fungicide in time, and then wrapped with electrical tape.
2. Be alert to phytotoxicity
Flowering--spray pesticides in the young fruit period, remember to be safe first. Carefully use pesticides such as emulsifiable concentrates, organophosphorus, triazoles, acetylene/triazole tin, or pesticides containing hidden components to avoid unnecessary fruit drop due to abuse, confusion, or excessive concentration; During the fruiting period, especially in sunny weather, use less or no such agents.
Improving Vision Extract,Marigold Flower Extract,Super Lutein Extract,Wild Blueberry Powder
Shaanxi Changsheng Industrial Co., Ltd. , https://www.cncsbio.com