1. Basic principles of fertilization for garden trees Fertilize according to purpose: Fertilization should not be applied blindly and indiscriminately, but should be analyzed and summarized scientifically and systematically. In order to obtain rich mineral nutrition, we should concentrate on layered fertilization, close to the root system, combine late-acting fertilizer with quick-acting fertilizer, combine organic fertilizer with mineral fertilizer, and combine base fertilizer with topdressing. In order to improve soil, lime can be used to improve acidic soil and sulfur can be used to improve alkaline soil. Such directional fertilization is like the right medicine, with twice the result with half the effort.
Fertilization: Trees need different nutrient elements in different phenological periods, and nitrogen fertilizer is needed in the whole growth period, but different amounts will gradually increase with the growth of new shoots and decrease with the thickening of trunk at the end of the growth of new shoots. At this time, applying more phosphate fertilizer is beneficial to the accumulation of nutrients in plants and promoting the rapid differentiation of buds into flower buds. When trees bloom, bear fruit and develop fruit, although various nutrients are urgently needed, potassium fertilizer is particularly important at this time, which can strengthen plant growth and promote flower bud differentiation. In the later stage of tree growth, the demand for nitrogen and water is generally small, so watering and fertilization should be controlled.
Fertilization due to the weather: trees need more fertilizer in spring and early summer, when soil microbial activity is weak, trees can absorb the least nutrients, and fertilization effect is the best. In addition, the absorption of fertilizer by trees is also affected by conditions such as heat, light and weather. The sunshine is abundant, the temperature is suitable, the photosynthesis is strong, and the root system absorbs high fertilizer. We should also consider the local climatic conditions and wintering conditions. The amount of forced fertilization and the number of topdressing blindly will cause the trees to grow white in the later period, and the cold will cause freezing damage when the low temperature comes. In addition, after heavy rain in summer, a large amount of nitrate nitrogen is leached from the soil, so topdressing nitrogen fertilizer in the morning or evening is the best.
Fertilization according to local conditions: Fertilization measures are closely related to soil conditions, and the types and dosage of fertilization should be determined according to soil properties and fertility. Sandy soil is a "hot soil" with loose texture, good air permeability, high temperature and low humidity. Pig manure and cow dung should be used as cold fertilizer, and fertilization should be deep rather than shallow. If you want to prolong the fertilizer efficiency, you can use semi-mature organic fertilizer or humus fertilizer, which should be used several times to avoid the phenomenon of "burning roots". Cohesive soil is a kind of "cold soil", with dense soil, poor air permeability, low temperature and low humidity, and strong fertilizer retention ability. Hot fertilizers such as horse manure and sheep manure should be selected, and the depth of fertilization should be shallow rather than deep, while the cut fertilizer must be fully decomposed and can be applied more at one time.
Look at fertilization: different fertilizers have different properties and different fertilization periods. Quick-acting fertilizers that are easily lost or volatilized and fertilizers that are easily fixed by soil after application, such as ammonium bicarbonate and calcium superphosphate, should be applied before trees need them. Slow-acting fertilizers, such as organic fertilizers, should be applied in advance because they need to decompose minerals before they can be absorbed and utilized by trees. Because the fertilizer efficiency of the same fertilizer is different in different application periods, the fertilizer should be applied in the period with the highest economic effect.
2. Types of fertilizers Different types of fertilizers have different nutritional components, properties, functions and functions, as well as different tree species, application conditions, methods and costs. They can be divided into organic fertilizers, inorganic fertilizers and microbial fertilizers.
Organic fertilizer: a fertilizer mainly composed of organic matter after animal and plant residues, human feces, soil and miscellaneous fertilizers are fully decomposed. It is a slow-acting and long-acting fertilizer, which is often used as base fertilizer.
Inorganic fertilizers: processed fertilizers and natural mineral fertilizers. Such as ammonium sulfate, urea, ammonium nitrate, ammonium bisulfate, calcium superphosphate, potassium chloride, etc. It is a quick-acting fertilizer and is often used as topdressing.
Microbial fertilizer: fertilizer made from soil microorganisms beneficial to plant growth. Such as nitrogen-fixing bacteria in bacterial fertilizer, rhizobia, phosphating bacteria and mycorrhizal bacteria in fungal fertilizer.
3, the period of fertilization To master the period of fertilization, we must first understand when plants need what kind of fertilizer. Generally divided into base fertilizer and topdressing. The application time of base fertilizer should be early, and the top dressing should be clever. Northern cities should apply base fertilizer around the autumnal equinox, especially ornamental fruit trees introduced and domesticated in the south. If it is too late, the trees can't stop growing in time, which will reduce their wintering ability. In addition, late-acting fertilizer should be applied, which has the following specific functions: ① Growth peak in autumn, easy healing of injured roots, and promotion of new roots. (2) Enhance the cold resistance and overwintering ability of seedlings. (3) It is beneficial to soil snow conservation, preventing soil drought in winter and spring, increasing ground temperature and reducing root freezing injury. ④ The decomposition time of organic matter is long and the degree of mineralization is high, so it can be supplied to trees in time for absorption and utilization in the spring of next year to promote the growth of roots. Basic fertilizer is rarely applied in spring, because the organic matter can not be fully decomposed, the fertilizer efficiency is slow, and it can not be supplied to the root system in early spring, and it will cause the secondary growth of new shoots in the late growth stage, which is especially unfavorable to flower bud differentiation and fruit development.
Topdressing period should be suitable. It can be divided into topdressing before flowering, topdressing after flowering and topdressing during flower bud differentiation. Fertilization before flowering is due to the low temperature and weak microbial activity in early spring, and there are few nutrients available in the soil, but flowers need a lot of nutrients when they germinate and bloom. Fertilization after flowering is to supplement the nutrients consumed by flowering, ensure the robust growth of branches and lay the foundation for fruit development and differentiation. Topdressing during flower bud differentiation is to solve the contradiction between fruit development and flower bud differentiation, which can ensure the formation of flower buds and reduce fruit drop.
The specific topdressing period depends on the region, tree species, varieties and tree age. Usually, ornamental tree species do not need fertilization after flowering, but need topdressing when flower buds differentiate, and topdressing is optional at later stage. It is very important for ornamental trees, fertilizer after flowering and fertilizer for flower bud differentiation. For flowers and trees that bloom in late spring, such as peony, fertilization after flowering and fertilization during flower bud differentiation can be combined into one, but fertilization must be applied before flowering. Roses are fertilized four times a year. Planting street trees, shade trees and landscape trees for 2-3 years, and topdressing 1-2 times a year during the growing period. At the same time, trees with symptoms of fertilizer deficiency can be topdressing at any time.
4. Fertilization amount usually depends on tree species, tree age, soil conditions and leaf surface analysis. Experience tells us that we should apply more fertile trees, such as ginkgo, rose, osmanthus, peony, phoenix tree and plum blossom, and less barren trees, such as Ailanthus altissima, Platanus acerifolia, Robinia pseudoacacia and Prunus armeniaca. For deciduous trees, the total fertilizer should be applied at a DBH of 350-700g per cm, and the DBH less than15cm should be halved, and those sensitive to chemical fertilizers should be halved. No chemical fertilizer is required for big trees, and 700-900 g (10-8-6 NPK mixed fertilizer) is used for young evergreen coniferous trees, and 2.44Kg of animal manure or seed powder organic fertilizer is applied per 100 m2. Apply 10-6-4 NPK fertilizer to adult trees, 1. 12 kg to evergreen broad-leaved trees and 0.98 kg to small forests. According to different soil properties, the amount of fertilization is also different. In mountainous areas, saline-alkali land, barren land and sandy land, green manure and peat should be applied more to improve the soil, and fertile soil with good physical and chemical properties can be applied less appropriately. Acid fertilizers, such as compost, acid peat acid, decomposed oak leaf soil and pine needle soil, should be applied to acid flowers and trees such as osmanthus fragrans, azalea and camellia. In addition, the amount of fertilization for trees in different growth periods is also different. For example, applying fertilizer twice in summer to the future 1-2 is to seize the key opportunity at the end of June and promote the formation of a large number of flower buds, so as to achieve the effect of blooming and falling in the next spring. Nitrogen fertilizer must be controlled in the late growth period and applied in May-July, otherwise the seedlings will grow white in autumn and cause freezing damage in winter. Therefore, the amount of fertilization is based on the symptoms of trees and the symptoms observed by naked eyes, constantly summing up experiences and lessons, and gradually exploring a set of economic and applicable relative quantity standards.
5. Fertilization method Surface fertilization: Do not apply chemical fertilizer within 30cm of the trunk, otherwise it will cause damage to the rhizome and dry foundation, not too shallow, and avoid simple ground spraying, and the depth is generally less than 60cm. According to the distribution and absorption function of tree roots, the horizontal position of fertilization should generally be around drip line with a crown projection radius of 1/3 times.
Gully fertilization: Gully fertilization is developed on the basis of applying nutrients as close as possible to the root system. It can be divided into annular furrow application and radiation furrow application.
Cave fertilization: dig holes in the fertilization area to fertilize.
Perforation and fertilization: drill a hole with a depth of 30-60cm every 60-80cm in the fertilization area, apply the rated amount of fertilizer evenly into the hole with a depth of about 2/3, and then plug the hole with sphagnum, broken manure or topsoil and step on it tightly.
Fertilization empty release bag: a certain amount of 16-8- 16 water-soluble fertilizer is heat-sealed in a double-layer polyethylene plastic bag and placed near the absorption root system. When the water vapor in the soil enters the bag through the micropores, the fertilizer absorbs water and overflows from the holes in the form of liquid for the roots of trees to absorb.
Nutrient nail fertilization: combine the fertilizer with the formula of 16-8- 16 with the patented resin adhesive, and drive it into the soil with a common woodworking hammer.
Foliage fertilizer: fertilizer made of urea, ammonium dihydrogen phosphate, potassium dihydrogen phosphate and potassium nitrate. The spraying amount is subject to the fact that a large amount of nutrient solution begins to drip from the leaves.