How to fertilize loquat scientifically? Master these technical points
How to plant loquat trees for high yield? What are the tips? Loquat is the earliest fruit variety to ripen in the year. High-quality loquat has large fruit, few seeds, bright orange-red skin, soft and juicy flesh, moderate sweet-sour taste, unique flavor and rich nutrition, with effects such as clearing heat, moistening the lungs, relieving cough and strengthening the stomach. In recent years, high-quality loquat...
How to fertilize loquat scientifically? When should more fertilizer be applied?Loquat tree fertilization techniques:
(1) Fertilizer amount and number of applications. The fertilizers commonly used in loquat cultivation include human excrement and urine, livestock and poultry manure, cake fertilizer, compost, garbage compost, burnt soil and chemical fertilizers. According to the mineral nutrient requirements of loquat growth and development, loquat is a plant with high potassium demand, and the potassium content of loquat fruit is almost 3 times that of nitrogen. Too much nitrogen fertilizer makes the fruit large, but the color and flavor are both strong, and the appearance and quality are poor; if there is too much potassium fertilizer, the sugar content of the fruit increases, but the flesh becomes coarse and hard. Therefore, various fertilizer elements should be properly combined.
For young loquat trees, fertilizer should be applied 5-6 times throughout the year, using the method of light fertilizer applied frequently, about once every two months. Apply 15-25 kg of decomposed dilute human (pig) excrement and urine (at a concentration of 20%-30%) per plant, or 150-250 g of imported compound fertilizer.
For adult fruiting loquat trees, fertilizer is generally applied three times a year, mainly arranged according to the fertilizer requirements and phenological periods of loquat. The fertilizer amounts summarized in different regions differ slightly. In the mountain loquat orchards of Putian, Fujian, 15-20-year-old vigorous trees are applied annually per 667 sq m with 10-13 kg of nitrogen, 8-10 kg of phosphorus and 13-15 kg of potassium. This can roughly be divided into the following applications:
① Post-harvest fertilizer is applied in May-June. It mainly supplements the nutrients consumed by fruiting, restores tree vigor, promotes vigorous summer shoot sprouting, and promotes good root growth and flower bud differentiation. It is mainly quick-acting fertilizer, combined with deep plowing, and a large amount of decomposed organic fertilizer is applied. The ratio of nitrogen, phosphorus and potassium fertilizer is generally 3:2:2. The fertilizer amount accounts for about 40%-50% of the annual fertilizer amount. For late-maturing varieties, it can be applied earlier before fruit harvest. Taking a plant yielding 35 kg of loquat fruit as an example, each loquat tree should be applied with 0.75-1.0 kg of imported compound fertilizer and 10-12 kg of chicken manure.
② Pre-flowering fertilizer is applied in September-October, when autumn flower bud differentiation has basically ended and flower spikes begin to appear, to provide the nutrients needed for flowering and fruiting and for sprouting vegetative autumn shoots, promote good flowering and improve the cold resistance of the plant. It is mainly organic fertilizer. The ratio of nitrogen, phosphorus and potassium fertilizer is generally 5:4:5. The fertilizer amount accounts for about 30%-40% of the annual fertilizer amount. Apply 10-13 kg of chicken manure per plant.
③ Spring shoot and fruit-strengthening fertilizer is applied after fruit thinning in February-March. The role of this fertilization is to promote the growth of spring shoots and roots, supply the nutrients needed for young fruit growth, promote young fruit enlargement, reduce fruit drop, and promote and plump the spring shoots. Quick-acting fertilizer combined with compound fertilizer is used, and the ratio of nitrogen, phosphorus and potassium fertilizer is generally 3:4:3. If the soil contains more phosphorus fertilizer, or if the current fruit load is relatively small, the proportion of phosphorus fertilizer can be reduced. If the tree vigor is not strong, increase the proportion of nitrogen fertilizer. The fertilizer amount accounts for about 20% of the annual fertilizer amount. Apply 30-50 kg of decomposed dilute human excrement and urine per plant, plus 0.3-0.6 kg of imported compound fertilizer and 0.25-0.5 kg of potassium fertilizer. February is the period with the largest root growth volume of the year, so the fertilization depth should be shallow to avoid damaging the roots.
In Putian, Fujian, loquat fruit growers apply 30-35 kg of chicken manure per plant after fruit harvest combined with plowing and earthing up. When the loquat tree bears many fruits, during the rapid fruit expansion period, spray 2-3 times with foliar fertilizer solution (0.2%-0.4% potassium dihydrogen phosphate, 0.2-0.4% urea and 0.2-0.3% potassium sulfate) before the rapid fruit expansion stage, once every 10 days.
(2) Fertilization methods. The fertilization effect on loquat is closely related to the fertilization method. The absorbing roots of loquat trees are mainly concentrated in the soil layer outside the outer edge of the tree canopy projection, and in production the fertilization site is at the canopy drip line. The chemotropism of loquat roots can also be used by applying fertilizer slightly separated from the place where roots are concentrated, guiding the roots to go deeper or expand outward and enlarging the root range. In addition, the characteristics of the fertilizer should also be considered, such as phosphorus fertilizer having poor mobility and being easily fixed by red soil. Therefore, phosphorus fertilizer should be applied deeply, in holes, and in the root zone to improve the absorption and utilization rate of phosphorus fertilizer. When applying superphosphate or bone meal, it should be mixed and composted with barnyard manure, stable manure or human excrement and urine, and applied after decomposition for better effect. The commonly used soil fertilization methods in loquat orchards include:
① Ring fertilization, also called wheel-shaped fertilization. Dig a ring-shaped ditch slightly outside the outer edge of the tree canopy, apply fertilizer into it, and then cover with soil. The ditch for basal fertilizer should be deeper, 40-50 cm; the ditch for topdressing should be shallow, 15-30 cm. The fertilization ditch should be moved outward year by year. This fertilization method has the advantages of simple operation and economical fertilizer use. However, it easily cuts some fast-growing horizontal roots, and the fertilization range is relatively small, which should be noted when choosing it.
② Plate-shaped fertilization. With the main trunk as the center, rake the soil outward into a circular plate shape. The part near the main trunk is shallow, and the farther from the main trunk, the deeper it is. There are also flat-bottomed fertilization plates. The raked soil is piled around the outside of the plate to form a soil ridge edge. After fertilization, cover with soil again. Because this method applies fertilizer relatively shallowly, water can easily damage roots, so it is suitable for topdressing. However, long-term use of this fertilization method will cause the loquat tree root system to move upward.
③ Radial ditch fertilization. With the trunk as the center, dig 6-8 radial strip ditches outward at 60-80 cm from the trunk, 20-30 cm deep, and apply fertilizer into the ditches. Change the ditch positions every other year or every other application to increase the absorption surface of the loquat tree root system. This method damages fewer roots, and if combined with ring fertilization, the fertilization effect is better. However, when digging ditches, avoid large roots so as not to damage them.
④ Strip ditch fertilization. Open strip ditches on both sides of the canopy drip line, or open strip ditches between rows or between plants in the loquat orchard. The ditch for basal fertilizer should be deeper, 50-60 cm; the ditch for topdressing should be shallower, 15-30 cm. Then apply fertilizer into the strip ditches and cover with soil. At the next fertilization, change to the other two sides and move outward year by year, combined with deep plowing, to mature the soil. This is a relatively good fertilization method.
⑤ Whole-orchard fertilization. For adult loquat orchards, the loquat tree roots have already spread throughout the orchard, so fertilizer can be evenly scattered over the whole orchard and then turned into the soil. If whole-orchard fertilization is combined with strip ditch fertilization or radial ditch fertilization, the fertilizer effect can be better brought into play. This method applies fertilizer relatively shallowly and easily causes the loquat root system to move upward.
⑥ Root-outside topdressing, also called foliar spraying. Root-outside topdressing is a method in which fertilizer is dissolved in water and directly sprayed onto loquat tree leaves so that the leaves directly absorb and utilize nutrient elements. The root-outside topdressing method is simple and easy to carry out, uses a small amount of fertilizer, and is absorbed and utilized quickly. Root-outside topdressing plays an important role in protecting flowers and fruits, promoting fruit development, improving quality, correcting nutrient deficiency symptoms, improving fertilizer efficiency (preventing soil chemical or biological fixation) and regulating loquat tree vigor. However, root-outside topdressing has a short duration of action and can only play an auxiliary role; it cannot completely replace soil fertilization.
Leaves are the center of the physiological and biochemical activities of loquat trees. The stomata and cuticle on the leaves have the ability to absorb nutrients. During the growing period, the underside of young leaves has a stronger ability to absorb nutrients. Generally, leaf nutrient absorption, like that of roots, is such that under acidic conditions anions are easily absorbed, while under alkaline conditions cations are easily absorbed. The trace elements used in root-outside topdressing are mostly simple-substance fertilizers. The suitable spraying concentrations of various fertilizers are shown in Table 4-5. When carrying out root-outside topdressing in spring, the concentration can be slightly higher; when carried out in the high-temperature and dry seasons of summer and autumn, the concentration should be appropriately lower to avoid fertilizer damage. When multiple fertilizers are mixed for use, the suitable concentration should be reduced proportionally. In addition, root-outside topdressing can also be carried out in combination with pesticide spraying for pest and disease control, but attention must be paid to the acidity and alkalinity of the fertilizer types and pesticide types; acidic and alkaline ones must not be mixed.
⑦ Special fertilization. In some hilly and mountainous areas, soil erosion is severe and nutrient elements are leached, easily causing deficiency symptoms. In addition, acidic soil is often deficient in phosphorus and calcium, while alkaline soil is often deficient in iron, and supplementing by soil fertilization methods has poor effect. For this reason, adopting some special fertilization methods can achieve better fertilization results.
First, root-sleeving fertilization. The period for root-sleeving fertilization should be during the root growth and absorption period, and the effect is better 5-7 days after flowers fade. The concentration used is generally slightly lower than the concentration used for root-outside topdressing. The method is: use a 10 cm x 15 cm plastic bag, fill it with 100-200 ml of fertilizer solution, and at about 30-50 cm inside the drip line on the east, south, west and north sides of the loquat canopy, take out a bundle of fibrous roots with many new roots; insert it into the plastic bag filled with fertilizer, and tie the bag mouth tightly to prevent water evaporation. This method has a relatively good effect on correcting deficiency symptoms.
Second, infusion fertilization. Infusion fertilization is generally carried out in early spring when tree sap flows, during the flower bud sprouting period, and one month before the fruit ripening period. It can protect flowers and fruits, and promote fruit development and flower bud differentiation. The fertilizer solution is 0.5 L of water, 6 g of urea, 4 g of potassium dihydrogen phosphate, 4 g of boric acid added in early spring, and a trace amount of triacontanol; when iron is deficient, 3 g of ferrous sulfate can be added. The device is like a hospital hanging bottle. The preparation method is: use a plastic bottle to hold the fertilizer solution so that it does not leak after the cap is sealed. Insert two needles into the cap and connect rubber tubes; one 40 cm long rubber tube is used for air intake, and the other 60 cm long rubber tube is then connected to a needle inserted into the tree body. Use a nail to make a hole in the main trunk of the loquat tree at 20 cm from the ground, reaching the xylem. Then, hang the bottle up, insert the needle into the hole, and after seeing the liquid seep out, seal the small hole tightly with white wax.
Third, drip irrigation fertilization. Drip irrigation fertilization is also an advanced fertilization and irrigation technique. It has the advantages of timely fertilizer supply, uniform fertilizer distribution, no root damage, protection of soil structure, less labor and less fertilizer use. However, at present, problems commonly exist in production such as water quality not meeting requirements, which easily causes emitter clogging. Further technical improvement is needed before it can be widely used in production.
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