Comprehensive low-yield and high-efficiency technology of citrus trees (orchards) with prosperous growth and low yield or no yield

Comprehensive low-yield and high-efficiency technology of citrus trees (orchards) with prosperous growth and low yield or no yield

Prosperous and low-yield or no-yield citrus trees (orchards), that is, citrus trees have been planted for many years, with luxuriant branches and leaves, reaching the age of high and stable yield, but they bear little or no fruit, and there is no economic benefit. For this kind of citrus tree (orchard), after the transformation by comprehensive measures, it can promote its fruit and appropriate more fruit in 1-2 years, and smoothly enter the high-efficiency period of high yield and stable yield.

I. the performance and main reasons for the formation of prosperous and growing citrus trees (orchards)

1. Performance

The citrus trees with prosperous growth and low yield are strong and prosperous, the trunk is high or high, the big branches in the crown are many and messy, the branch order is not good, the tree shape is irregular, the only long branches are many, chaotic and slender, the spring shoots are less, the summer and autumn shoots are more and slender; some new shoots grow directly outside the crown, the canopy is closed and poor permeability, serious diseases and insect pests; the main root is thick and deep, the lateral roots are many and developed; the leaves are many and thin, the leaves are large or large, and the leaves are dark or light green. This kind of citrus tree (orchard) has a large amount of flowers every year, but the flower and fruit drop is serious, and there is little or no fruit setting, so there is no economic benefit.

two。 The main reasons for its formation

① is overnourished. The soil of citrus orchard is too deep and fertile, which leads to the overgrowth of trees, which leads to the imbalance between vegetative growth and reproductive growth.

Fertilization in ② is not scientific. Citrus orchards do not attach importance to the balanced application of organic fertilizer and nitrogen, phosphorus and potassium, or partial application or attention to nitrogen fertilizer, resulting in prosperous trees, many and long branches, many and thin leaves, large leaves and dark leaves, which disturbs the balance of vegetative growth and reproductive growth.

③ planting is too dense (or not in time to cut down or transplant temporary trees). When the crown is enlarged and closed, there is no effective crown control in time, and there is no thinning or removal of some trees, resulting in overlapping branches between trees and poor ventilation and light transmission conditions. When Wenzhou mandarin is grafted on the rootstock of Zhu Kui, the tree is easy to grow.

④ tip control is not scientific. The spring, summer and autumn shoots of citrus trees put out too late, and the shoots grow fast but not full, especially if there are too many late autumn shoots, such as dry, hot, freezing and other bad weather, the shoots are easy to shed leaves or be frozen, which greatly affect the flower bud differentiation, reduce the quality of flowers, and affect the flowering and fruit setting next year.

II. Root control, rational fertilization, flower and fruit protection of prosperous citrus trees (orchards)

1. Root control

① trenched and cut off roots. It is best to trench and cut roots from the end of August to early October. According to the situation, a trench with a width of 50 cm 60 cm, a depth of 50 cm 60 cm and a self-defined length can be dug at 20 cm on one or both sides of the water drip line of the crown, and the shallow soil side root with a diameter of 1 cm to 2 cm can be cut off by 20% of the root. For trees that grow too much, holes can be made on one or both sides to the inside of the crown and the main root or part of the thick lateral root can be cut off with a sharp knife. When cutting off the root, no matter the thicker root or the thinner root, the wound should be flattened with a sharp knife and coated with fungicides such as lime water to promote wound healing and prevent infection of soil-borne diseases. After trenching and root cutting, the tree potential and weather can be seen, and the ditch and root drying on a sunny day is selected for about 10 days, so as to better control the moisture in the root system and soil and improve the effect of inhibiting growth. If the soil organic fertilizer is insufficient or lack, it should be combined with trenching, root cutting and layered application of rotten pig and cow manure. Trenching and root cutting should be carried out continuously, once a year, until prosperous and long citrus trees (orchards) enter into high and stable yield.

② ploughs and cuts the roots in deep. Every year, before the summer shoot and after the autumn shoot stops growing, select fine weather for deep ploughing, hoe part of the fine roots, inhibit the excessive absorption of fertilizer and water by the roots, effectively control the shoot emergence and growth, promote the shoot enrichment and sturdiness, accelerate the nutrient accumulation and flower bud differentiation in the tree, and improve the flower quality. The position of deep ploughing starts from 0.8 to 1.2 meters from the trunk and gradually expands outward, and the depth of mid-ploughing changes from shallow to deep, and it is suitable for 16 to 20 centimeters.

two。 adequate manuring

Prosperous citrus trees (orchards) are mostly because they do not pay attention to the combined application of nitrogen, phosphorus and potassium fertilizer, apply little or no organic fertilizer, and tend to apply chemical fertilizer (especially nitrogen fertilizer), which promotes the shoot growth. Farm manure such as pig and cow manure has comprehensive nutrition and slow decomposition, and contains a lot of organic matter, which can improve soil, increase the ability of soil fertilizer and water conservation, fertilizer supply and water supply, and enhance the stress resistance of trees.

Balanced fertilization of ①. The suitable ratio of N, P and K fertilizer for growing trees (orchards) is 2RV 1RU 1.6. Nitrogen fertilizer should not be applied partially or repeatedly, it is best to apply a small amount of nitrogen fertilizer for many times, and strictly control the growth of branches in the middle and later stage, or only apply nitrogen fertilizer, so as to avoid excessive growth.

② base fertilizer and topdressing should be applied according to the situation. Prosperous trees should control the number of times and application amount of topdressing. Base fertilizer: focus on increasing the proportion of base fertilizer, the amount of base fertilizer should account for more than 60% of the total fertilizer application, of which organic fertilizer should account for 70% to 80%. Topdressing: the spring topdressing of prosperous trees should be applied little or not according to the situation, and trees with excessive growth and hopeless fruit do not apply spring fertilizer, and trees that can blossom and bear fruit in that year, such as fertilization, each tree can be applied in ditch or hole to 50 kg of water-rotten human and animal manure (or 1 kg of multi-component compound fertilizer). Attention should be paid to the application of stable fruit and strong fruit fertilizer, but each plant should be applied in ditch or hole to 50 kg of mature human and animal manure and 1 kg of superphosphate (or 1-1.5 kg of multi-component compound fertilizer). Autumn fertilizer should be controlled, and overgrown trees can not be applied after autumn fertilizer.

3. Protect flowers and fruits

Before ① blossoms. Foliar spraying 0.3% potassium dihydrogen phosphate + 0.1% borax solution twice, each time spraying 30kg / mu, each interval of 10: 15 days, can increase the fruit setting rate.

② flower bud stage. Foliar spraying 0.3% potassium dihydrogen phosphate + 0.1% magnesium sulfate solution once, spraying 30-40 kg per mu, can significantly increase the fruit setting rate. In this period, if the dry and hot weather is higher than 30 ℃ and the air relative humidity is less than 60%, the leaf should be sprayed twice with 500x solution (including amino acids and chelated trace rare elements), 30kg / mu each time, once every 10 days, which has a better effect of stabilizing flower and fruit.

③ thank you for the queen. Foliar spraying of 610mg / L 210mg / L 210mg / L or 0.3% potassium dihydrogen phosphate solution 1x twice, each time spraying 30kg / mu, once at intervals of 10mg / 14 days, has a better fruit protection effect.

④ young fruit expansion stage. Foliar spraying 0.3% potassium dihydrogen phosphate + 0.5% urea solution twice, spraying 30kg / mu each time, once every 10 / 15 days, the effect of preventing and controlling fruit drop is good.

III. Pruning of prosperous and growing citrus trees (orchards)

① winter pruning. The thin and weak branches, dry and withered branches, overlapping branches, branches of serious diseases and insect pests, branches without light, upright branches that disturb the shape of the tree, etc., should be cut off from the base; cross branches should be pulled or cut short; other branches should be cut long and light to remove some of the bore branches to improve the permeability in the crown. Excessive closure of the tree, from the base to remove 1 or 2 large side branches in the crown, open the skylight, let the light shine into the crown. Long and prosperous trees with cross-sealed branches should be retracted, pruned or thinned some of the drooping branches and secondary or tertiary shoots, not short-cut, in order to promote reproductive growth. It is forbidden to re-cut multiple hair in prosperous trees, otherwise it will aggravate the contradiction between shoots and fruits.

② thinning and removing over-dense trees. Too dense cultivation of citrus trees is harmful but not beneficial. For over-dense trees (orchards), thinning and removing some trees in winter or early spring can relieve canopy closure and improve ventilation and light transmission.

③ sprouting, heart-picking and tip control. Unused buds or shoots should be erased as soon as possible. When the branch tip grows to 30 centimeters long, it is necessary to pick the heart to promote the branch tip to be full and stout. When growing trees show buds, spring shoots should be timely regulated according to flower quantity and flower quality, and the growing branches should be heart-picked and controlled at the right time. For the blooming and fruiting trees, the summer shoots should be wiped out as soon as possible, and the buds should be wiped every 6-7 days from late May, and stopped from July 10-15, which can effectively alleviate the contradiction between the top and fruit, stabilize the fruit with the shoot and press the fruit with the fruit. When the shoot growth is too prosperous, spraying 15% paclobutrazol wettable powder 120-150 times liquid, each time spraying 30-40 kg per mu, the effect of controlling overgrowth is better, and can promote the branches to be full and sturdy.

④ pull branches and so on. For the upright and prosperous long branches left in use, dry support, pulling branches and heavy hanging branches should be used from May to August, so as to increase the angle of the branches and control the overgrowth, so as to form a good tree shape and branch shape.

⑤ twist. From September to October, when the flower bud differentiates, the new shoot is sprained at the base, or the angle of the branch is pulled out with the rope, or the branch tip is rolled up to change the direction of the shoot growth, so that the shoot grows horizontally or obliquely, which can control the transport intensity of fertilizer and water to the shoot, effectively restrain the vegetative growth and accelerate the formation of the fruiting mother branch.

⑥ ring cut or constricted branch. For excessively prosperous citrus trees, on May 10-20, late September and mid-October every year, the bases of main branches, secondary main branches and large branches can be cut by rotating (staggered) semilunar rings with a sharp knife, and fine iron wire can also be used to hang the bases of main branches, secondary main branches and large branches. the depth is suitable to reach the xylem without harming the xylem, which can control the transport of nutrients to the upper branches and leaves in a short time, obviously inhibit the growth of branches and leaves, and accelerate the transformation from vegetative growth to reproductive growth. It can promote flowers and preserve fruit. Do not ring-cut or constrict branches of weaker trees or drought, so as to avoid adverse reactions and affect the growth of trees, flowers and fruits. The branches constricted with thin wire will be released by the end of October.

IV. Pest control of prosperous and growing citrus trees (orchards)

Wangchang citrus trees (orchards) have poor permeability and serious diseases and insect pests, so special attention should be paid to prevention and control. The important thing for the prevention and control of diseases and insect pests is early prevention and early treatment, local or individual tree diseases and insect pests should not be used in the whole garden, but should be treated. Do not use multiple or multiple drugs to control diseases and insect pests that can be controlled by one drug or one class of drugs, so as to avoid drug resistance or drug resistance, and increase the cost and insecurity of drug use (drug residues).

The main diseases and insect pests are canker, scab, resin disease, anthrax, bituminous disease, red spider, aphid, tick tick, yellow spider, shellfish, leafhopper, leafhopper, leaf miner, butterfly and so on.