
My soil test shows I am low in both P and K and I only have money to fertilize with one. Which do you suggest would be most beneficial to my crops (corn / beans)?
Robert Mullen, Ph.D.

Robert Mullen, Ph.D.
Nutrien
Director of Agronomy
To say Dr. Robert Mullen is passionate about agriculture would be an understatement. He holds a Bachelor of Science degree in ag business from Cameron University, along with a Master of Science degree in plant and soil science and a Ph.D. in soil science from Oklahoma State University. In addition, Dr. Mullen has been published in a variety of scientific and trade journals. But it’s not just his academic accomplishments that make him unique. It’s his unwavering ability to take complex data and — in simple terms — explain how it impacts a farmer’s bottom line. Dr. Mullen delivers the kind of insightful observations that can lead to a more profitable business. As a leading agronomy expert, Dr. Mullen has a goal to further educate farmers on best management practices that improve their yields and maximize their return on investment.
While, ideally, you should apply both nutrients if they are limiting production based upon soil test, there is some research to suggest that just applying K can be more beneficial than just applying P if both are limiting. Also, check out our Nutrient ROI Calculator to show you the dividends you can reap with an investment in both P & K.