Formula for calculating fertilizer application rate
I. Basic Situations for Determining Fertilizer Application Rates
The basic fertility conditions of the soil to be planted.
Regarding the basic fertility of the soil, simply put, it's about whether the soil is vigorous or not. The main basis for judgment is the growth condition of the previous crop, which is easy to determine. Another way is to have the soil tested, but this is very difficult to achieve.
② Choices for Growing Vegetables
Different vegetables have different demands for fertilizers. For instance, Chinese cabbage and lettuce require more nitrogen fertilizer. Tomatoes and cucumbers need more nitrogen fertilizer in the early growth stage, but more phosphorus and potassium fertilizers in the middle and later stages. Potatoes and carrots need more potassium fertilizer, followed by phosphorus fertilizer, but less nitrogen fertilizer.
③ Types of Fertilizers
In simple terms, these are organic fertilizers and chemical fertilizers. Organic fertilizers provide basic nutrients and improve soil quality. Chemical fertilizers, on the other hand, are quick-acting fertilizers that take effect rapidly. The combination of the two yields better results.
④ Planting environment
Drought and excessive rainfall both have an impact on fertilization. When the temperature is high and there is abundant rainfall, fertilizers decompose quickly. The principle of fertilization in such cases is to apply small amounts frequently. Additionally, in greenhouse cultivation, the environment is relatively sealed, and nutrients are less likely to be lost. In this situation, it is recommended to use more organic fertilizers and less chemical fertilizers.
Second, there is also a calculation formula for the amount of fertilizer.
Fertilizer application formula:
The application rate of a certain nutrient element (kg/acre) = (Total nutrients required for target yield - Nutrients available in soil) ÷ Nutrient content in fertilizer × Fertilizer utilization rate
The meaning of this formula:
The total amount of nutrients required for the target output
Target yield (kilograms per acre) × Nutrient requirement (kilograms) per 1000 kilograms of this vegetable produced
② The amount of nutrients that the soil can provide
Soil nutrient measurement value (mg/kg) × 0.15 × Soil nutrient utilization coefficient.
③ Nutrient content in fertilizers
For example: The urea content is 46%, and this represents the content.
④ Fertilizer Utilization Rate
For example: Urea has a nitrogen content of 46% and an actual utilization rate of 35%.
III. Simple Algorithm for Actual Fertilizer Application Amount
Soil testing and formulation is currently the most scientific method, but ordinary users definitely don't have the ability to do this. I'll briefly share a simple algorithm for calculating the fertilizer dosage for ordinary users.
The amount of organic fertilizer used
Generally speaking, applying 3 to 5 tons of organic fertilizer per acre can basically meet the basic needs of crop growth. This organic fertilizer replenishes the nutrients in the soil and improves the soil quality, reducing the use of chemical fertilizers.
② Fertilizer application (chemical fertilizer)
Fertilization principle: Fertilize based on the condition of the plants, and carry out fertilization in stages.
Monitor the growth of the seedlings and apply fertilizer accordingly. This means observing the growth conditions of the seedlings and applying fertilizer when necessary. For example, if the leaves are small, the color is pale, or the seedlings are small, it indicates a lack of nitrogen fertilizer. Applying nitrogen fertilizer will solve the problem.
Implement staged fertilization. Fertilize according to the growth cycle of the crops, such as during the flowering stage, fruit setting stage, and enlargement stage, etc., and carry out fertilization separately for each stage.
Summary:
If conditions permit, it is recommended to adopt soil testing-based fertilization methods. Currently, this is the most scientific approach. In cases where conditions are not favorable, a combination of organic fertilizers and chemical fertilizers can be used. Organic fertilizers improve the soil, while chemical fertilizers ensure the supply of nutrients. This way, sustainable agricultural development can be achieved.
