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I. Gravity Division (Level) Matching Method The geopotential division (level) matching method is to use soil survey, cultivated land fertility survey and local field test data to divide the soil into several grades according to the fertility level, or to draw a field with equal fertility. As a formula area, re-apply data and field trial results, combined with local practical experience, estimate the appropriate fertilizer types and their application rates in this formula area. The advantage of this method is that it is relatively simple, and the proposed fertilizer dosage and measures are close to local experience. The method is simple and the people are easy to accept. The disadvantage is that the limitations are large. Each formula can only be adapted to areas with small differences in production levels, and it relies on more general experience and is not targeted for specific fields. In the process of promotion, it is necessary to combine experimental demonstrations and gradually expand the proportion of scientific testing methods and theoretical guidance.
Second, the target yield allocation method The target yield allocation method is based on the composition of crop yield, the principle of the supply of nutrients from the soil itself and fertilization to calculate the amount of fertilizer. First determine the target yield, and the amount of nutrients needed to achieve this yield, then calculate the amount of nutrients that the crop needs to supplement in addition to the nutrients supplied by the soil, and finally determine how much fertilizer to apply. Including nutrient balance method and ground force subtraction method.
Third, the field test method The principle of the field test method is to conduct a multi-point field test by simple single comparison, or the application of more complex orthogonal, regression and other experimental design, so as to select the optimal treatment to determine the amount of fertilizer application.
1. Fertilizer effect function method: Single-factor, two-factor or multi-factor multi-level regression design is used to carry out the point test. The yields of different treatments are mathematically calculated to obtain the fertilizer effect equation between yield and fertilization amount. According to its functional relationship, the different yield-increasing effects of different elemental fertilizers and the combined effects of various fertilizers can be visually seen, the upper and lower limits of fertilization can be determined, and the amount of economic fertilization can be calculated as the basis for actual fertilization. The advantage of this method is that it can objectively reflect the single and comprehensive effects of fertilizers and other factors. The accuracy of fertilization is high, which is in line with the actual situation. The shortcoming is that the regional limitations are strong. Different soils, climates, farming, varieties, etc. need to be arranged in different experiments. .
2, nutrient abundance index method: This is one of the field test methods. This method utilizes the correlation between the measured values ​​of soil nutrients and the nutrients absorbed by the crops, and the different crops are passed through field trials, and the measured values ​​of the soils are classified according to the yields obtained by different soil nutrient values. Make a comparison table of nutrient abundance and fertilization amount. In practical applications, as long as the soil nutrient value is measured, the amount of fertilizer applied can be determined from the control list.
3, nitrogen, phosphorus, potassium ratio method: This method is also a kind of field test method. The principle is to obtain the best ratio of various nutrients in a certain crop with different yields through field experiments, and then to quantify a nutrient according to the ratio of various nutrients. To determine the amount of fertilizer used in other nutrients, such as nitrogen, phosphorus, potassium, phosphorus, and potassium. It should be understood that the characteristics of the three systems of formula fertilization are based on crop fertilizer requirements, soil fertilization characteristics and fertilizer effects. Under the conditions of organic fertilizer, the appropriate dosage and proportion of nitrogen, phosphorus, potassium and micro-fertilizer are proposed. And its corresponding fertilization techniques. At present, there are many methods of formula fertilization applied in the country. From the basic principles, it can be divided into three major systems: soil fertilization method, fertilizer effect function method and crop nutrition diagnosis method.
Soil testing and fertilization is a formula fertilization technology developed on the basis of chemical determination of soil fertility. Through the determination of effective nutrients in the soil, the soil nutrient abundance is determined, and fertilization suggestions are proposed. The method has the advantages of being simple, fast, and inexpensive, and can be carried out year by year, and can serve each plot, and plays a micro-guidance role in formula fertilization. However, the measurement methods are different, and the effective nutrient indicators are also different. At the same time, the fertility indicators of different soils and different crop types are also incomparable, and there is no macro guidance and regulation function. The checksum correction of the parameters also needs to be continuously improved. Nowadays, more nutrient balance methods and soil fertility index methods have been developed on this basis.
The fertilizer effect function method is based on fertilizer field trials and biostatistics. Considering the yield of crops as a function of fertilizer production, a fertilizer effect test is set on a representative plot to obtain a benefit function of crop yield corresponding to each fertilizer amount (or combination). Therefore, in order to obtain more accurate results, the method requires a longer cycle and a higher test cost. At the same time, due to the climatic differences between the years, its reproducibility is poor. It is now mainly used for macro guidance. Crop nutrition diagnosis method is a fertilization technology based on plant nutrition chemistry. The disadvantage of this method is that it can only qualitatively reflect the level of nutrients in crop plants, but can not accurately determine the amount of fertilizer to be applied, because there are many factors affecting the absorption and utilization of nutrients by crops. The basic formula of soil testing and formula fertilization (nutrient balance method) is to achieve the balance between nutrient supply and demand between crops and soil. According to the difference between crop fertilizer requirement and soil fertilization, the amount of fertilizer needed to achieve planned yield is obtained. One way. The formula for calculating the nutrient balance method is: the fertilization amount of a certain nutrient === (the crop target yield and fertilizer amount - the soil fertilization amount) / (the fertilizer nutrient content × the fertilizer utilization rate), the crop target yield and fertilizer amount = The biological yield of the crop × the average content of a nutrient in the crop; the amount of soil fertilization is calculated from the nutrient content absorbed by the crop when no nutrient is applied; the fertilizer utilization rate is calculated based on the field test results conducted on the plot. Got it. It can be seen from the above formula that in order to master the nutrient-balanced formula fertilization technology, it is necessary to grasp the relevant parameters such as crop fertilizer requirement, soil fertilizer supply, fertilizer utilization rate, and effective nutrient content in fertilizer.
Source: Heilongjiang Province Soil Testing Formula Fertilization Leading Group
Three types of six methods of soil testing and formula fertilization technology Introduction The soil testing formula fertilization methods promoted in various places have three types of six methods: the first type is the land division method: the second type is the target yield method, including the nutrient balance method and the difference in soil fertility. Subtraction; the third category is the field test method, including the fertilizer effect function method, the nutrient abundance index method, and the NPK ratio method.
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