If you’d ask any soil fertility expert about the soil, they’ll definitely mention these three alphabets – N, P, and K. What does N, P, and K or N P K stands for?
Well, plants require essential macronutrients to grow and produce biomass. Along with carbon dioxide (CO2) and water (H2O), they require three major macronutrients which are Nitrogen (N), Phosphorus (K), and Potassium (P). Calcium (C), which helps them thrive.
Although a plant requires a different set of macronutrients to grow, NPK is the largest amount of nutrients that they require. Hence, they are often considered the most important nutrients in the soil. If you’re wondering, NPK is mentioned in the ratio “Number-Number-Number” that you can find in the packet of each fertilizer.
Before talking about Fertilizer numbers (N P K), let’s know about fertilizer in person.
What is Fertilizer?
Fertilizer is a chemical substance or natural substance added to soil to increase its fertility. The soil that yields fewer crops is often dressed with fertilizer to grow its yields.
Fertilizer can be of both organic fertilizer and synthetic fertilizer (chemical) i.e. it can come from organic materials like plants, leaves, wood ash, bone meal, blood meal, feather meal, seed meal, etc., or an inorganic matter like lab-produced chemicals.
Most often, the farmers may add different kinds of supplements along with complete fertilizer to increase crop production. However, fertilizer is the key to preparing healthy soil for a good yield. Fertilizers can work in two ways. One is enhancing the growth of plants and the other is enhancing the effectiveness of the soil by modifying its water retention and aeration.
A fertilizer is classified in several ways; single nutrient fertilizer, multi-nutrient fertilizers, or micronutrients. A single nutrient fertilizer only contains one nutrient, e.g., N, P, or K, while multi-nutrients may include different proportions of N, P, and K. Most complete fertilizers or all-purpose fertilizers come in as granular fertilizers, water-soluble fertilizer, liquid fertilizer, and all-purpose fertilizer.
Plants require a lot of different macronutrients in order to grow well. The three major nutrients are:
Nitrogen
Nitrogen helps for leaf growth and enhances the rich green color in healthy lawn grasses and other plants. It’s a slow-release fertilizer that is highly water-soluble. Without the optimum level of nitrogen in the soil, the active growth of the plant could slow down or even turn pale.
Phosphorus
Phosphorus primarily helps in the development of root growth, flowers, seeds, and fruit. It refocuses energy on strong root development and flower and fruit production. Organic fertilizer also helps plants to use nutrients efficiently. A lack of phosphorus could lead to weak plant roots and no flower or fruit. It could also be harmful to overuse phosphorus because the runoff could mix into waterways and pollute the drinking water.
Plumeria plants are a fast-growing tropical tree that produces masses of fragrant blooms. To make them suitable as the house plant, you should avoid feeding them more Nitrogen for foliar feeding. Choose a complete fertilizer with N P K ratio of 10-30-10 or 10-50-10 or soluble fertilizers with maximum pounds of Ammonium Phosphate. When choosing a fertilizer, chose dry granules with excess phosphorus.
Potassium
Potassium helps for strong stem growth, movement of water in plants, and promotion of flowering and fruiting. It helps regular root and top growth along with protecting the plant from diseases and pests.
Other than these, plants require these secondary nutrients in organic fertilizer: calcium, magnesium, and sulfur, and micronutrients: copper, iron, manganese, molybdenum, zinc, boron, silicon, cobalt, and vanadium, ammonium phosphate, and ammonium nitrate.
What are Fertilizer Numbers and why are they important?
All organic fertilizer products must provide uniform information to help consumers compare products easily. Hence, every complete fertilizer label carries three conspicuous numbers, usually right above or below the product name. These three numbers form what is called the fertilizer’s N-P-K ratio.
The N-P-K number reflects the availability of nutrients or percentage inside the organic fertilizer. For example, a 100-pound bag of lawn fertilizer 20-0-4 reveals that it contains 30 percent nitrogen, 0 percent phosphorus, and 4 percent potassium.
The kind of lawn fertilizer you need to buy and in what order of nutrient proportion can only be determined after a soil fertility expert tests your soil. The test will help determine the deficiency or sufficiency of N, P, or K in the soil for long-term fertility.
Is it important?
Well, here is how the whole mechanism of macronutrients comes into play.
Different plants and crops have different needs for nutrients. Plants that are leafy will require more nitrogen, while plants with fruits will require a higher proportion of potassium and phosphorus.
For optimal plant growth, sufficient amounts of nutrients should be available in the root zone of the crops. While most nutrients are provided by the soil itself, others need to be added or replenished time and again.
Farmers should know the condition and nutrient content of their soil. When they decide to grow a plant or crop, they’d know what proportion of N, P, and K they should add with other micronutrients to optimize the production.
Most nitrogen is present in the soil in organic form; however, it should be mineralized into mineral forms before the plant’s strong roots can suck it up. Likewise, phosphorus is also present in the soil but mainly in chemical forms that differ from insolubility.
The availability of each nutrient must be optimized to ensure the growth of plants. Too few nutrients can lead to hampered growth and low yields while more of them can cause adverse effects on growth and yield. The quality of harvest entirely depends on the optimum use of each nutrient.
What should you know?
The mobility of nutrient materials in soils strongly differs. Nitrogen and Potassium are water-soluble and are mobile in the soil while phosphorus is rather immobile in soil. You would know this from the visible signs of nutrient deficiency in the plants. Yellowing of leaves, the occurrence of brown spots on the leaf, unripe fruits, or immature growth are the signs of nutrient deficiency.
You should always consult with soil fertility experts or agriculturists to understand more about your soil problems. A basic NPK test can help determine if your soil is lacking enough nitrogen, phosphorus, or potassium. Soils with the optimum levels of NPK could also lack secondary macronutrients such as calcium and magnesium or micronutrients like copper and iron.
Getting started
These tips will help you get started with determining your soil fertility, what amount of fertilizer you’d need for soil amendments, and how to use it.
- Get a soil sample test first if you don’t have any idea about your soil fertility. Find out the soil’s pH level and follow any recommendations from the testing lab.
- Next, calculate the square footage of your garden beds. Multiply the length by width (l x b).
- Use the soil recommendations and your square footage to decide what type of fertilizer is required and how much you need for your area.
- Decide what fertilizer you need (purpose fertilizer, water-soluble fertilizer, or synthetic fertilizer, and garden fertilizer) and the proportion of nutrients for what you want to grow. Buy enough fertilizer to treat the area.
- Read the bag or bottle thoroughly before applying fertilizer. Apply at recommended rates at all times.
- Nitrogen is best in slow-release forms. You can use granular fertilizer as well. Add it to soil weeks before planting so the plant can use it as it needs it. It’s highly water-soluble.
- Use slow-releasing organic amendments that break down incrementally and boost the plant as it needs it, rather than all at once.
- Lawns or gardens can be fertilized three times a year. This will encourage healthy growth, minimize runoff, and feed the soil during peak demand times.
- Aerate before the first application weeks ago, thatch before the second, and apply any weed control before the last to maximize your use of fertilizers in these larger areas.
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