Fertilizer 101: The Big 3 - Nitrogen, Phosphorus and Potassium

It’s the earth’s cultivated cropland that keeps humanity alive and thriving. Plants provide food, fiber, housing and a host of other benefits, and fertilizer plays a key role in this process. As the world population is expected to exceed 9 billion by 2050, fertilizer will be needed more than ever to boost crop production to keep people fed and healthy.

All growing plants need 17 essential elements to grow to their full genetic potential. Of these 17, 14 are absorbed by plants through the soil, while the remaining three come from air and water.

Generations of soil science have yielded knowledge of how to test nutrient levels in soil, how plants take them up and how best to replace those nutrients after harvest. That’s where fertilizer comes in.

Nitrogen, phosphorus and potassium, or NPK, are the “Big 3” primary nutrients in commercial fertilizers. Each of these fundamental nutrients plays a key role in plant nutrition.

Nitrogen is considered to be the most important nutrient, and plants absorb more nitrogen than any other element. Nitrogen is essential to in making sure plants are healthy as they develop and nutritious to eat after they’re harvested. That’s because nitrogen is essential in the formation of protein, and protein makes up much of the tissues of most living things. Below is a picture of corn that is nitrogen deficient. 

The second of the Big 3, phosphorus, is linked to a plant’s ability to use and store energy, including the process of photosynthesis. It’s also needed to help plants grow and develop normally. Phosphorus in commercial fertilizers comes from phosphate rock. Below is a picture of corn that is phosphorus deficient. 

Potassium is the third key nutrient of commercial fertilizers. It helps strengthen plants’ abilities to resist disease and plays an important role in increasing crop yields and overall quality. Potassium also protects the plant when the weather is cold or dry, strengthening its root system and preventing wilt. Below is a picture of corn that is potassium deficient.

The Big 3—nitrogen, phosphorus and potassium—provide the foundational nutrients of today’s commercial fertilizers. Keep following The Voice as we continue to explore fertilizer in-depth in the weeks ahead.  

For more information on the the "Big 3" nutrients in commercial fertilizers, check out the 4R Educational Modules on nitrogen, phosphorus and potassium.