Elements of fertilization of pollution-free vegetables
1. What nutrients are needed for vegetable crops - essential elements
Nutritional components of plants---fertilizer nutrients - N, P, K, Ca, Mg, S, Fe, Zn, Cu,
2. How much nutrients are needed for vegetable crops?
1. Common characteristics of vegetables and fertilizers: Vegetables are highly intensively cultivated crops. Despite the variety and variety of vegetables, the growth and development characteristics and product organs are different, but compared with food crops, no matter the amount of fertilizer needed. Or there are considerable differences in the demand for different nutrients, but their commonalities are as follows:
(1) Large nutrient requirements The average value of the nutrient content of various vegetables is compared with the nutrient content of wheat. The average nitrogen uptake of vegetables is 4.4 times higher than that of wheat. The phosphorus uptake is 0.2 times higher, the potassium uptake is 1.9 times higher, the calcium uptake is 4.3 times higher, and the magnesium uptake is 0.5 times higher.
(2) Nutrients with a lot of vegetables In addition to the seedless, vegetables are harvested when the seeds are not finished, and their fresh vegetative organs or reproductive organs are used as commodities for people to eat. Therefore, the nitrogen, phosphorus and potassium nutrients contained in the vegetables during harvest are significantly higher than those in the field crops.
(3) Special needs for certain nutrients Although different types of vegetables have large differences in nutrient absorption, there are certain special requirements compared with other crops, such as:
1 vegetables like nitrate nitrogen; 2 the demand for potassium and calcium is large; 3 vegetables are sensitive to boron deficiency and molybdenum.
These nutritional characteristics are important basis for rational fertilization of vegetables.
2. Characteristics of nutrient absorption by vegetable crops
The root crown ratio is small, and the root burden is heavy.
The root system is shallow and the absorption range is small. The soil nutrient supply intensity is required.
Fast growth and high absorption
Low soil temperature and weak absorption capacity
3. How much nutrients can the soil provide? Soil fertility
Soil testing: standard methods, rapid testing methods
The status of soil nutrient supply in China: most soils are deficient in nitrogen, 50% of soil is deficient in phosphorus, 30-40 soil is deficient in potassium, trace elements such as zinc, iron, boron and manganese are scarce, and medium-sized elements such as calcium, magnesium and sulfur are some crops. The lack of seriousness, especially in greenhouse vegetables.
4. What nutrients are added for supplementation?
1. Organic fertilizer: farmyard manure, commercial fertilizer
(1) The role of organic fertilizers in vegetable production
A. Provide various mineral nutrients and organic nutrients required for crops. In the process of decomposition, organic fertilizers release the nutrients contained in them through mineralization for the growth and development of crops.
B. Increase soil organic matter content and increase soil fertility.
Improve soil water retention and fertility; facilitate the formation of soil aggregate structure and improve soil physical properties; provide organic carbon source to promote soil microbial activity; various active enzymes secreted by animal digestive tract and various enzymes produced by microorganisms These substances can greatly increase the activity of enzymes in the soil after entering the soil; improve the availability of poorly soluble phosphorus and trace elements in the soil.
C. Increase crop yields and improve the quality of agricultural products.
Reduce nitrate in vegetables
Reduce nitrite content
Increase vitamin C content
In short, the application of organic fertilizer can improve soil activity and biological reproduction.
Ability to improve soil adsorption, cushioning and stress resistance.
(2) Development trend of organic fertilizer
A. The use of traditional organic fertilizers is shrinking
Reason: low nutrient content; slow fertilizer efficiency; production and use of organic fertilizers requires more manpower, material resources, etc.
B. Commercialization, conversion of organic fertilizer processing into commercial organic fertilizer
Features: Price is cheaper than chemical fertilizer (equivalent nutrient); application is more convenient; organic fertilizer has advantages in fertilizing soil
Attention to the problem: harmless treatment, decomposing
2. Inorganic fertilizer: single fertilizer, compound fertilizer, organic and inorganic compound fertilizer
(1) Main nitrogen fertilizer types
Ammonium nitrogen fertilizer: ammonium sulfate, ammonium chloride, ammonium hydrogencarbonate, ammonia
Nitrate nitrogen fertilizer: potassium nitrate, ammonium nitrate, calcium nitrate
Amido ammonium: urea
Lime nitrogen
(2) Compound fertilizer refers to a fertilizer containing three elements of nitrogen, phosphorus and potassium or any two of them in chemical fertilizer components.
Nutrient identification
A. The percentage of total nutrients of N, P2O and K2O should be indicated, expressed as a percentage of N-P2O5 - K2O, for example: 20-10-10 is expressed as 15% N, 15% P2O5, 15% K2O Compost.
B. Binary compound fertilizer, with "0" indicating a nutrient element missing, for example: 18-46-0, is a nitrogen-phosphorus binary compound fertilizer, and for example: 13-0-44 is a nitrogen-potassium binary Compound fertilizer.
C. If medium or trace elements are added, they are not indicated in the packaging container and quality certificate.
The compound fertilizer contains trace nutrients indicated at the position behind K2O, for example: 12-12-12 -2 (Zn), which is a ternary compound fertilizer containing zinc.
(3) Advantages of compound fertilizer: comprehensive nutrient content, high content; good physical properties, easy to apply; less secondary components, no adverse effects on soil; ratio diversity, which is conducive to targeted selection and application; cost reduction and cost saving .
Disadvantages of compound fertilizers: A. Many crops have different characteristics for nutrients at each stage of growth, and soil fertility and nutrient release in different regions are also very different. Therefore, it is difficult to simultaneously combine binary fertilizers with relatively fixed nutrient ratios. Meet the requirements of various soils and various crops. B. The laws of soil nutrients moving in the soil are different. Therefore, it is difficult to fully meet the special needs of nutrients in a certain period of the crop in terms of the location and release rate of the nutrients.
(4) Special compound fertilizer is a special compound fertilizer for different components and proportions of specific soils and crops, such as vegetable special compound fertilizer in China, special fertilizer for zinc (applicable to some crops on zinc-deficient soil).
Controllable slow release fertilizer: the release time and release of nutrients are consistent with the fertilizer requirement of crops, which can not only meet the nutrient absorption of crops, but also minimize the loss of fertilizer and improve the utilization rate of fertilizer. It is one of the development directions of current fertilizers, and it is also a multi-disciplinary cutting-edge technology that closely combines modern chemical engineering production engineering and plant nutrition regulation technology in the world.
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