The soil testing formula fertilization instrument is based on soil testing and fertilizer field experiment. According to crop fertilizer requirement, soil fertility performance and fertilizer effect, based on rational application of organic fertilizer, nitrogen, phosphorus, potassium and medium and trace elements are proposed. The amount of fertilizer applied, the period of application, and the method of application.
Purchase considerations
1. Go to a professional production or sales unit to buy.
2. Check the stability error of the soil fertilizer meter, and remind the users to check the stability of the instrument when purchasing the instrument. As the saying goes, the instrument is not afraid of being inaccurate, and the instrument with unsatisfactory stability is absolutely unusable and must be returned. The method of inspection is: (1) Turn on the power and warm up the instrument for 5-10 minutes. (2) Cover the instrument's light-shielding cover and adjust the instrument so that the display reads 0 (absorbance) and 100 (transparency). (3) Observe the change in instrument readings. Within one to two minutes, the display shows no drift (transparency measurement), the digital drift does not exceed 0.3% within five minutes (transparency measurement); the digital drift does not exceed 0.5% within twenty minutes (transparency measurement), 0.001 (Absorbance measurement); digital drift does not exceed 0.7% (transmittance measurement), 0.002 (absorbance measurement) within 30 minutes. If the difference between the maximum and minimum readings of the instrument display value exceeds the above reading, the stability of the instrument is not acceptable. Such instruments cannot be used as soil fertilizer testing, and can not be used as a fertilizer testing instrument. They can only be used as deceptive props.
Standard parameters: (1) Stability: A value (absorbance) drifts less than 0.003 within three minutes; (2) Repeatability: A value (absorbance) is less than 0.005; (3) Linearity error: less than 3.0%; (4) Sensitivity: Red light ≥ 4.5 × 10-5 Blue light ≥ 3.17 × 10-3 (5) Wavelength range: red light 620 ± 8nm blue light 440 ± 8nm.
3. Select the soil tester with complete basic test items. There are many test items for soil and fertilizer instruments. In addition to soil nitrogen, phosphorus, potassium and organic matter, there are also trace elements, soil pH, conductance, heavy metals, fertilizer nutrient determination, and plant nutrition diagnosis. When purchasing, you must pay attention to the needs of the basic project test of soil testing and fertilization. These basic projects are available nitrogen (where all nitrogen is used), available phosphorus, available potassium and organic matter.
4. Choose the fastest soil fertilizer meter for testing the whole process. The speed of testing is important to reduce testing costs. When purchasing the soil fertilizer meter, it mainly depends on the speed of the whole process of the soil, the calibration speed of the instrument, the speed of drug preparation and the application of other rapid test supporting technologies.
5. Choose the soil fertilizer meter that is suitable for you. The use conditions of the soil fertilizer meter users can be divided into two categories: one is the unit without laboratory, such as the township agricultural technology station, the crop hospital, the agricultural science and technology demonstration village. Units with such conditions of use generally use a photoelectric colorimetric soil fertilizer meter with good portability and compatibility. The second category is units with laboratories, such as county soil fertility stations and agricultural resource inspection centers. This type of unit has laboratory cooperation, does not require the soil and fertilizer instrument to be compatible and portable, desktop or portable photoelectric colorimetric soil fertilizer meter can be used.
6. Choose a good soil fertilizer meter for after-sales service. There are two types of soil fertiliser production units; one is the manufacturer that only provides the instrument (or is responsible for training and maintenance) regardless of the effect, and the other is the manufacturer that provides comprehensive after-sales service for the user. This type of powerful unit also provides Speed ​​measurement fertilization technical guidance (some manufacturers take speed measurement and conventional comparison correlation to provide conversion factor, this is very unscientific, because in many places, speed measurement and conventional are simply not comparable). And cooperate with local soil and fertilizer systems or other capable agrochemical service units to establish a service network in the provinces and autonomous regions. When purchasing the soil fertilizer meter, compare the service capabilities of the manufacturers, and choose manufacturers with good after-sales service and strong professional capabilities.
7. The soil fertility instrument is a practical agricultural instrument whose mission is to serve the broad-based agricultural technology promoters and the farmers to provide scientific fertilization guidance to farmers. It is different from general instruments and has a unique low cost. A scientific technical device with portability, speed, accuracy and practicality.
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