1、Estimating thresholds of nitrogen, phosphorus and potassium fertilizer

In this study, we proposed a method that utilizes allowed ranges of partial nutrient balance and yield to estimate the threshold of nitrogen (N), phosphorus (P), and potassium (K) fertilizer applied to rice (Oryza sativa L.) fields in China.

2、Fertilizer Types and Calculating Application Rates

As N is much more mobile in soils and must be applied every year to nonlegumes, N requirements are based on the crop to be grown and the soil type that influences yield goals. These recommendations are generally made in conjunction with soil test reports.

3、How To Calculate Fertilizer Application Rate For Any Crop

To calculate fertilizer application rate, first determine how much nitrogen, phosphorus, and potassium your soil contains. You need to do a soil test by collecting soil samples from different parts of your field and sending them to a laboratory for analysis.

4、How To Calculate NPK, Application Rate & Fertilizer Requirement

For example, in a 50 pounds bag of 10-20-10 NPK fertilizer, there are 5 pounds of nitrogen (10% of 50 pounds), 10 pounds of phosphorus (20% of 50 pounds), and 5 pounds of potassium (10% of 50 pounds). Use this simple formulae for calculating the NPK values present inside the fertilizer bag.

How Much Fertilizer Per Square Meter for a Vegetable Garden? A

Nitrogen (N): Apply 10–20 grams per square meter. Phosphorus (P₂O₅): Apply 5–10 grams per square meter. Potassium (K₂O): Apply 5–15 grams per square meter. For a balanced approach, a complete fertilizer with a ratio like 10-10-10 or 5-10-10 can be used.

How to Calculate the Amount of Fertilizer Needed for Your Lawn

One pound of nitrogen or mixed fertilizer is recommended per 1,000 square feet of lawn and your particular fertilizer contains 20% nitrogen. Refer to Table 1 to convert this to five pounds of fertilizer that should be applied per 1,000 square feet.

How to Calculate Fertilizer Rates for Lawn and Garden

Recommended fertilizer rates can be used to determine the amount of fertilizer to apply to a garden area or lawn. Use these simple calculations to determine the amount of fertilizer needed.

Fertilizer Calculator

The lawn fertilizer calculator tells you how much fertilizer you need to achieve a desired rate of N, P or K, and how many bags to purchase.

How Many Kilograms of Potassium Fertilizer per Mu of Rice is Appropriate?

The proportion of nitrogen, phosphorus and potassium; the amount of pure nitrogen required for rice per mu of about 450 kg is 10 to 12 kg, the phosphorus pentoxide is 4.5 to 5.5 kg, and the potassium oxide is 13 to 16 kg.

How Much Fertilizer Do I Apply?

Since nitrogen, potassium, and phosphorus are all needed, a complete fertilizer—such as 8-8-8, 10-10-10, 13-13-13, or 17-17-17—will work, but different amounts of each are needed. Simply divide the pounds of fertilizer needed, in this case 80 pounds, by the percentage of the nutrient in the bag.

The appropriate amount of nitrogen and potassium fertilizers for one mu (approximately 0.067 hectares) depends on crop type, soil conditions, and growth stages. Here are some guidelines:

1. Nitrogen Fertilizer

Nitrogen fertilizer is essential for plant growth, promoting the development of stems, leaves, flowers, and fruits. A general recommendation is 5-10 kilograms per mu. For poor soil or weak crops, increase the dosage slightly. excessive use may cause overly vigorous growth, reducing yield and quality.

2. Potassium Fertilizer

Potassium fertilizer supports root development, disease resistance, and fruit quality. A typical application is 10-20 kilograms per mu. Adjust upwards for potassium-deficient soils, but avoid overuse, as it may lead to rapid growth and compromised yield/quality.

3. Phosphate Fertilizer

Phosphate fertilizer enhances root growth, disease resistance, and fruit quality. Apply 10-20 kilograms per mu. Increase for phosphorus-poor soils, but excessive use may spur excessive growth, harming productivity.

4. Organic Fertilizer

Organic fertilizers (e.g., farm manure, animal compost) improve soil organic matter, structure, and water/nutrient retention. A standard rate is 200-500 kilograms per mu. Overapplication can lead to nutrient excess, disrupting plant growth.

5. Micronutrient Fertilizer

Micronutrient fertilizers (e.g., iron, manganese, zinc) supplement essential trace elements. Apply 2-5 kilograms per mu. Excessive use may accelerate growth and reduce yield/quality.

6. Fertilization Methods

• Broadcasting: Sprinkling fertilizer evenly over the field (suitable for large areas).
• Furrow Application: Placing fertilizer in irrigation ditches (for irrigated fields).
• Hole Application: Applying directly into planting holes (for small plots). Choose methods to optimize fertilizer efficiency.

7. Timing

• Spring: Best for fertilization due to rapid crop growth.
• Autumn: Minimal application, as crop growth slows. Additional fertilization is needed during peak growth and pre-harvest stages.

8. Fertilization Ratios

Adjust ratios based on crops, soil, and fertilizer types:

• Nitrogen : Phosphate = 1:1
• Nitrogen : Potassium = 1:1
• Nitrogen : Organic = 1:2
• Nitrogen : Micronutrients = 1:1 These are baselines; modify according to specific conditions.

Rational fertilization ensures healthy crops, high yields, and quality. Pay attention to fertilizer type, quantity, proportions, and methods. Avoid overapplication to prevent soil pollution and poor growth.

Note: Adjust recommendations based on local soil tests, crop requirements, and environmental factors.