How to calculate NPK compound fertilizer 15–15–15 formula？

In this article, we will calculate how to calculate the formula of 15–15–15 and 18–18–18 compound fertilizer according to the proportion of nutrients required by plants.

Step by Step Guide of how to calculate different types fertilizer formula

Compound fertilizer is a kind of fertilizer that mixes different types of fertilizers in a certain proportion. By mixing different fertilizers, it can meet the different needs of crop growth and improve crop yield and quality. The calculation method of compound fertilizer formula mainly includes the following steps:

Step 1: First to determine what is the crop nutrient requirements:

Different crops have different nutrient requirements at different growth stages, so it is first necessary to determine the types and proportions of nutrients required by the crops. This can be determined through soil nutrient analysis, crop nutrient requirement tables, and expert advice.

Step 2: Try to understand the nutritional content of fertilizers

Before calculating the compound fertilizer formula, you need to understand the nutritional components of each fertilizer, which mainly include nitrogen, phosphorus, potassium and trace elements. These components are crucial for the growth and development of crops. This information can be obtained by checking the instructions on the fertilizer package, relevant literature, and guidance from experts.

Step 3: Start to calculate the npk fertilizer formula ratio

Depending on the nutrient needs of the crop and the nutrient content of the fertilizer, the fertilizer ratio can be determined through some mathematical calculations. The following is a commonly used fertilizer nutrition calculation method:

1. Calculate the total amount of nutrients required by crops, such as nitrogen, phosphorus, potassium, etc.
2. Determine the percentage of nutrient elements contained in each fertilizer.
3. Calculate the weight required for each fertilizer based on the total amount of nutrient elements required by the crop and the percentage of nutrient elements in each fertilizer.
4. According to the calculation results, the required weight ratio of each fertilizer is obtained, that is, the formula.

What is Nitro Based Compound Fertilizer NPK-Best Guide 2024

Now lets give a exmple of how to calculate the 18–18–18 fertilizer formula

For example, during growth, crops require a ratio of nitrogen, phosphorus, and potassium of 3:1:2.

• Given That

1. The nitrogen content in fertilizer A is 20%.
2. The phosphorus content is 10%, and the potassium content is 30%;
3. The nitrogen content in fertilizer B is 40%.
4. The phosphorus content is 20%.
5. The potassium content is 40%.

Assuming that the total amount of nutrients required by crops is 100 grams, based on the ratio of nitrogen, phosphorus, and potassium, it can be calculated that the amount of nitrogen is 30 grams, the amount of phosphorus is 10 grams, and the amount of potassium is 20 grams.

• Calculation Process are as follows:

Calculated based on the percentage of fertilizer content

1. The amount of nitrogen in fertilizer A is 30g*1/2=15g.
2. The amount of phosphorus is 10g*1/2=5g.
3. The amount of potassium is 20g*2/3=13.33 gram.
4. The amount of nitrogen in fertilizer B is 30g*1/2=15g.
5. The amount of phosphorus is 10g*1/2=5g.
6. The amount of potassium is 20g*2/3=13.33g.

• To sum up, the formula ratio of fertilizer A and fertilizer B is 15:5:13.33

Step 4: Adjust the 18–18–18 npk compound fertilizer formula according to actual local soil conditions.

Depending on the actual situation, the npk compound fertilizer formula sometimes needs to be adjusted. For example, if the soil is too high in one nutrient, the amount of fertilizer containing that nutrient can be reduced; if the amount of one nutrient is insufficient, the amount of fertilizer containing that nutrient can be increased.

Conclusion: How to calculate the fertilizer formula.

In this article we introduce how to calculate the formulas of 15–15–15 and 18–18–18 compound fertilizers. To summarize briefly, we take the nutrient ratio required by plants and put it into our formula to calculate and finally get the result. The desired compound fertilizer formula. Of course, at the end of the article, we also remind all readers that all formula calculations are at a theoretical level. In reality, the composition and quality of fertilizers will vary. The quality of the land is different from the situation of each piece of land, so in When fertilizing, the formula should be adjusted appropriately according to the conditions of the crops and the land and recorded.

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