What Fertilizer to Use for Nursery Stock? The Correct Methods of Fertilizing and Top-Dressing
Nursery stock refers to young trees with a root system and a stem. Concentrated production areas for nursery stock are found throughout China. There are many kinds of nursery stock with good economic returns, and the fertilizer used for different nursery stock varies, while the techniques of fertilizing and top-dressing also have many key points.
1. Fertilizer for nursery stock
Fertilizers are usually divided into two major categories: organic fertilizers and inorganic fertilizers.
Organic fertilizer is also called farmyard manure. It includes human and livestock manure and urine, compost, green manure, peat (grass peat), humus fertilizer, and so on. Its characteristics are many types, wide sources, and complete nutrients; it not only contains abundant major elements such as nitrogen, phosphorus, and potassium, but also contains trace elements, hormones, and antibiotics, and so on. It can improve the physical and chemical properties of the soil, and its fertilizer effect is released slowly and lasts a long time. It is an indispensable fertilizer for raising soil fertility and improving the quality and yield of ornamental nursery stock.
Inorganic fertilizer is also called chemical fertilizer. It includes nitrogen fertilizer (ammonium sulfate, ammonium bicarbonate, ammonium nitrate, urea), potassium fertilizer (potassium chloride, potassium sulfate, potassium dihydrogen phosphate), phosphorus fertilizer (calcium superphosphate, ammonium phosphate), and trace element fertilizer (ferrous sulfate, boric acid). Its characteristics are that the nutrient elements such as nitrogen, phosphorus, and potassium it contains all exist in the form of inorganic compounds; the nutrients are single, ‘the content is high, the fertilizer effect is fast, the volume is small, it is convenient to transport, and it is clean and hygienic and easy to use.
Before application, you must understand the properties of various fertilizers and the characteristics of nutrient uptake by tree species, so that you can fertilize rationally, improve the growth quality of nursery stock, and save on fertilizer costs. Long-term single use of inorganic fertilizer will make the soil compact, so it is best to apply it together with organic fertilizer.
2. Methods of applying base fertilizer to nursery stock
Base fertilizer: the soil fertility of nursery land is generally poor. In order to improve the soil, base fertilizer is indispensable, and sandy land needs it even more. Generally, organic fertilizers such as stable manure, compost, oil cake, or manure are often used as base fertilizer, and are mostly broadcast before land preparation and turned into the plow layer.
Mixing calcium superphosphate and the like with organic fertilizer gives better results. The organic fertilizer used must be decomposed and fermented, otherwise fertilizer damage will occur. The application rate of base fertilizer should depend on the soil fertility conditions and plant species; generally, 150-200 kg of base fertilizer should be applied per 100 sq m of nursery land.
3. Methods of top-dressing nursery stock
Top-dressing supplements the deficiency of base fertilizer to meet the needs of ornamental nursery stock at different growth and development stages, and inorganic fertilizer (chemical fertilizer) is often used as top-dressing.
(1) Look at the type of fertilizer
Top-dressing for nursery stock generally uses quick-acting fertilizers, such as plant ash, ammonium sulfate, urea, ammonium chloride, potassium chloride, and so on. These chemical fertilizers must be completely crushed and should not be applied in lumps. Organic fertilizers such as human and livestock manure water and compost can also be used for top-dressing, but they must be fully fermented and decomposed; never use raw manure, and the concentration should be dilute. Nitrogen fertilizer has strong mobility in the soil and can be applied shallowly to permeate into the root distribution layer and be absorbed by the nursery stock; potassium fertilizer has poor mobility, and phosphorus fertilizer has even poorer mobility, so it should be applied deeply to where the roots are densely distributed.
(2) Fertilize according to the weather
The number of fertilizer applications and the amount applied are determined according to weather conditions. When the temperature is low, the nursery stock absorbs little; when the temperature is high, the root system grows vigorously and absorbs more fertilizer. It is best to choose clear weather and dry soil when fertilizing. On cloudy and rainy days, because the tree roots absorb water slowly, not only are nutrients not easily absorbed, but the fertilizer is also easily washed away by rain, causing waste. In dry weather, it is best to use the wet application method, that is, mix the fertilizer with water into liquid fertilizer and apply it evenly on the nursery land; when rainfall is moderate, the dry application method can be used, that is, apply the fertilizer in furrows, and the depth of the furrow application should be in the root distribution layer to facilitate the absorption of fertilizer by the nursery stock.
(3) Fertilize according to the soil
Pay attention to applying different types of fertilizer because different soil types contain different kinds and amounts of nutrient elements. For example, on calcareous soil or strongly acidic nursery soil, phosphorus deficiency is prone to occur, so attention should be paid to increasing the application of phosphorus fertilizer, especially increasing the amount of phosphorus fertilizer. General soil is mainly given nitrogen fertilizer; if the soil is already sufficient in nitrogen, the proportion of phosphorus and potassium fertilizer used should be increased.
Soil texture differs, and nutritional conditions and fertilizer retention capacity also differ, so the fertilization methods also differ. If the soil has good fertilizer retention capacity, the amount used each time for top-dressing can be larger and the number of times can be fewer; for sandy loam nursery land with poor fertilizer retention capacity, the number of top-dressings should be greater and the amount used each time should be smaller.
(4) Apply according to the seedlings
The growth of nursery stock is generally divided into four stages: the emergence stage, the seedling stage, the fast-growth stage, and the hardening stage.
At the emergence stage, the nursery stock cannot manufacture nutrients on its own, and its nutrition mainly depends on the nutrients stored in the seeds; the seedling stage refers to the period from when true leaves appear on the aboveground part of the seedling and lateral roots are produced underground until the growth of the seedling rises greatly, and at this time it is relatively sensitive to nitrogen and phosphorus; the fast-growth stage is when both the aboveground and underground parts of the nursery stock grow at the same time, and the demand for nutrients is large, so the amount and frequency of nitrogen fertilizer should be increased, and phosphorus and potassium fertilizer should be applied in proportion. In the later stage of growth, in order to promote the hardening of nursery stock and improve resistance, nitrogen fertilizer should be stopped in good time; at the hardening stage, excessive growth should be prevented and fertilizer application should be stopped to improve the resistance of the nursery stock. Generally, one-year-old sown seedlings need more nitrogen and phosphorus fertilizer in the early growth stage to promote the growth and development of young roots, need large amounts of nitrogen, phosphorus, potassium, and other elements in the fast-growth stage, and in the later growth stage mainly need potassium, supplemented by phosphorus, to promote the lignification of young stems. For large-sized nursery stock that has already formed, with strong roots and farther distribution, fertilization should be deep and the range should be large, such as Chinese pine, ginkgo, silk tree, and tree of heaven; for those with shallow roots, fertilization should be shallow and the range should be small, such as plane tree, shrubby false indigo, and flowering shrubs.