How to use fruit tree fertilizer correctly? A detailed explanation of fertilization methods
Fellow farmers must be cautious when buying fertilizer. Since some farmers do not understand fertilizer production, they must pay attention to the following issues when purchasing, which will bring you absolute benefits: the "four don'ts." First, don't covet small bargains and ignore quality by buying fake or inferior fertilizer, so as to avoid causing...
The correct use of fruit tree fertilizer is one of the key links in producing pollution-free fruit.The correct use of fruit tree fertilizer is one of the key links in producing pollution-free fruit. The national agricultural industry standard promulgated and implemented by the Ministry of Agriculture last year also made clear provisions on the fertilizer use guidelines for producing green food (fruit), requiring that the fertilization principle should be based mainly on organic fertilizer, supplemented by chemical fertilizer, to maintain or increase soil fertility and soil microbial activity, while the fertilizers used should not have adverse effects on the orchard environment and fruit quality.
Now, in combination with the implementation of the standard and the demand for fertilizer in fruit production, I will explain fruit tree fertilizer and its use.
I. Types of fertilizer
(1) Types of fertilizer permitted for use 1. Farmyard manure: Farmyard manure refers to various organic fertilizers obtained from local materials and used locally. It is made by accumulating large amounts of biological matter, animal and plant residues, excreta, and biological waste, and is rich in organic matter and humus as well as various macroelements and microelements needed by fruit trees, and also contains hormones, vitamins, and antibiotics. It mainly includes compost, waterlogged compost, stable manure, biogas manure, green manure, crop straw manure, mud manure, and cake fertilizer, etc. 2. Commercial fertilizer: Commercial fertilizer refers to fertilizer that, according to national laws and regulations, is managed by the national fertilizer department and sold in commercial form. It includes commercial organic fertilizer, humic acid fertilizer, microbial fertilizer, organic compound fertilizer, inorganic (mineral) fertilizer, and foliar fertilizer, etc. It is mainly processed into organic fertilizer from animal and plant residues, excreta, other biological waste, and diseased plant materials as raw materials, or made into fertilizer in the form of inorganic salts by physical or chemical industrial methods from minerals. 3. Other fertilizers: Refers to fertilizers made from organic by-products of the food and textile industries that do not contain toxic substances, as well as organic matter such as bone meal, bone glue residue, amino acid residue, poultry and livestock processing waste, and sugar factory waste, and registered and permitted for use by the agricultural department.
(2) Fertilizers prohibited for use 1. Untreated urban ** or ** containing metals, rubber, and harmful substances; 2. Nitrate nitrogen fertilizer and undecomposed human excreta; 3. Fertilizer products that have not obtained registration approval.
II. Fertilization methods
(1) Apply base fertilizer early and in large amounts. At present, the organic matter in most orchards is less than 1%, and in some orchards it is even below 0.5%, far below the requirements of high-quality and high-yield orchards, so the amount of base fertilizer must be increased. If the dual needs of tree growth and soil improvement are considered at the same time, the application rate of organic fertilizer should be controlled at the standard of 2-3 jin of fertilizer per jin of fruit. Therefore, for a medium-yield orchard with a yield of about 1500 kg per mu, the amount of organic fertilizer should not be less than 3000 kg. The most suitable time to apply base fertilizer is before and after fruit harvest: apply before harvest for weak trees and after harvest for vigorous trees. The next best time is in spring when the flower spikes have just begun to emerge. For orchards in mountainous areas that are dry and have no water for irrigation, since irrigation cannot be carried out immediately after applying base fertilizer, the base fertilizer can also be applied during the rainy season by taking advantage of the rain. However, the organic fertilizer must be fully decomposed, the fertilization should be done quickly, and care should be taken not to damage the coarse roots. When the source of organic fertilizer is insufficient, on the one hand, straw and weeds can be used as supplements mixed with organic fertilizer; on the other hand, the limited organic fertilizer should still follow the principle of ensuring local application and ensuring the concentrated distribution layer of the root system, using concentrated hole application to fully exert the fertilizer effect of organic fertilizer. Concentrated hole application means digging holes about 50 cm deep and 30-40 cm in diameter from the edge of the tree canopy inward, with the number depending on the amount of fertilizer, then mixing organic fertilizer with soil at 1:3 or adding some straw, filling the holes, and then watering. In addition, phosphate and potassium fertilizers, and even zinc fertilizer and iron fertilizer, can be mixed with organic fertilizer to improve their utilization rate.
(2) Rational topdressing 1. Proper topdressing of nitrogen fertilizer: Nitrogen is the basis for the growth and fruiting of fruit trees. Within a certain limit, increasing nitrogen fertilizer can significantly improve the photosynthetic performance of leaves and enhance tree vigor and yield. But exceeding the limit can easily cause excessive growth of branches and leaves, making it difficult to form flowers and reducing fruit quality. Moreover, after applying a large amount of nitrogen (often followed by heavy irrigation after fertilizing), because the absorption capacity of the root system is limited, the excess nutrients will be leached and lost, causing great waste of fertilizer, and even fertilizer damage when a single application is too large. Therefore, while emphasizing increased investment in orchards, the needs of the tree and the benefits of fertilization must also be considered, and blind large inputs should be avoided. The suitable amount of nitrogen fertilizer should be determined comprehensively according to soil fertility, fertilizer retention capacity, and tree type. Generally, for 1-2 year old trees, 50-100 g of urea can be topdressed per tree each time; for 3-4 year old trees, 150-200 g; for trees after 5-6 years, generally no more than 15 kg of urea per mu per topdressing, and the annual urea dosage per mu is about 30-45 kg. 2. Apply nitrogen according to the site: Under conditions of insufficient organic matter, properly topdressing quick-acting nitrogen fertilizer on barren land can significantly improve the photosynthetic performance of leaves, thereby increasing the accumulation level of photosynthetic products in the tree, playing the role of "increasing carbon with nitrogen." The accumulation of photosynthetic products in turn promotes root growth and improves root absorption capacity. The weak trees on barren land and the difficulty in forming flower buds are all related to the level of carbon and nitrogen metabolism in the plant. Therefore, appropriately increasing the amount of nitrogen fertilizer, using nitrogen to increase carbon, and letting nitrogen fertilizer lead the way are effective measures for strengthening trees, forming flowers, and producing yield in orchards on barren land. The method of nitrogen topdressing also differs with different soils. After spring nitrogen topdressing, the fertilizer generally begins to take effect in 10-15 days; in summer, generally 5-7 days; in autumn, between the two. This mainly varies with the level of soil organic matter and adsorption capacity. Generally, after 20 days of topdressing (in high-temperature seasons), the fertilizer effect is no longer very significant. In mountainous sandy barren land with low organic matter content and poor fertilizer retention, nutrients are seriously leached with water, the effective period of fertilizer is shorter, and soil nitrogen loss often occurs during the rainy season in July-August. Therefore, topdressing in mountainous sandy land should be applied frequently and in small amounts, so that the nutrients in the water can seep into the concentrated distribution layer of the root system. After the rainy season, a small amount of nitrogen fertilizer can be topdressed to make up for leaching losses. On soils with relatively high salinity and alkalinity, when the pH value reaches above 7.5, the content of available phosphorus in the soil is generally low, and fruit trees often show the phenomenon that fine branches do not easily form flowers due to phosphorus deficiency. Topdressing phosphate fertilizer on such soils (soil application or foliar topdressing) is indispensable for early fruiting and high yield. Phosphate fertilizer applied to the soil is easily fixed, so it is best to mix it with high-quality organic fertilizer rich in nutrients. 3. Apply fertilizer according to the tree: After the root system of the fruit tree absorbs nutrients, nutrient distribution is limited by the nutrient center, that is, nutrients are preferentially transported to the most metabolically active parts and further promote the growth and development of these parts. For example, when topdressing during vigorous new shoot growth, more fertilizer enters the vigorously growing new shoot parts and further promotes vigorous growth; after the shoot leaves stop growing, the central advantage of the vigorous growing parts weakens or disappears, the difference in nutrients entering various organs after topdressing decreases, distribution becomes more balanced, and the supporting effect on weak parts of the canopy (such as spurs) is relatively greater, which is conducive to bud differentiation. Therefore, when tree vigor is different, the amount of flowers and fruit is different, and the purpose of fertilization is also different, so the timing of fertilization should also not be the same, and fertilization must be combined with plant type. For weaker-growing trees, including "small old trees," in order to strengthen the growth of branches and leaves, nutrients should be supplied mainly when new shoots are growing. It is best to topdress several times before germination and in the early growth stage of new shoots, combining topdressing with irrigation to promote new shoot growth and make weak branches stronger. For trees that grow vigorously but have few flowers or grow excessively without fruiting, in order to moderate excessive branch and leaf growth and promote bud differentiation on spurs, topdressing should avoid the vigorous growth period and be carried out after new shoots stop growing. The type of fertilizer should also be adjusted according to the tree. Practice has proved that nitrogen fertilizer has an obvious effect in promoting branch and leaf growth, and more nitrogen fertilizer is used to rejuvenate weak branches. Phosphate and potassium fertilizers help moderate excessive growth, so for excessively vigorous and non-fruiting trees, the amount of phosphate and potassium fertilizer should be increased, and the amount of nitrogen fertilizer appropriately reduced. Topdressing is best spread evenly in the tree dish, immediately followed by light hoeing to mix the fertilizer evenly, and then watering. When the tree dish is covered with grass, it can be spread directly on the grass and then washed down with water; or one corner of the covering grass can be pulled open, spread on the soil surface, then watered down, and the grass covered again.
(3) Foliar fertilization. Foliar topdressing of fruit trees is the direct spraying of fertilizer on the aboveground branches and leaves of the tree, which can make up for insufficient root absorption or serve as an emergency measure. Foliar spraying is not disturbed by factors such as the number of new roots and soil physical and chemical properties, and directly enters the branches and leaves, which is conducive to more quickly changing the nutritional status of the tree. Moreover, after foliar topdressing, nutrient distribution is not limited by the growth center, and the distribution is balanced, which is conducive to moderating tree vigor and strengthening weak parts. In addition, foliar topdressing is also often used for correcting deficiency symptoms of zinc, iron, boron, and other elements and for applying compound fertilizers. However, foliar spraying cannot replace rhizosphere topdressing; the two have their own characteristics and should complement each other. After foliar spraying, the response of leaves to fertilizer elements is most obvious in 10-15 days, then gradually decreases, and disappears by the 25th-30th day. Therefore, if you want to exert an effect during a certain key period, spray continuously once every 15 days during this period. After autumn harvest and during the spring and summer flower and fruit development periods are the two important periods for foliar topdressing. It will promote good flower organ development, high fruit set rate, and thick and strong spurs. In addition, the correction of deficiency symptoms of zinc, boron, and other elements should also pay attention to the two key periods of autumn and early spring; the effect of spraying fertilizer for correction in these two periods is generally better than in the growing season.