Soil Testing: From The Fields To The Lab

Soil Management

Soil Testing: From The Fields To The Lab

Robert Mullen, Ph.D.

Robert Mullen

Robert Mullen, Ph.D.


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.

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Through soil analysis, labs can help growers and certified crop advisors develop a more scientifically sound fertilizer program. Taking the time to soil sample and get things tested is going to help improve profitability.

To get the best results from soil testing and make good decisions based on the results, follow these three key suggestions:

Step One: Sample consistently and frequently

Essentially all nutrients vary by depth, so what is the best sampling depth? Some states recommend a six-inch sample and some states recommend an eight-inch sample – just be consistent about depth. The nutrient concentration in soil varies over time, so we should standardize the time that the soil sample is taken.

Step Two: Collect enough cores to represent your entire farm

There is large spatial variability of soil test results, so we need to take many cores to make composite soil samples that represent the area. Make sure you thoroughly mix the cores that represent the area when you’re generating that composite. You don’t want any one core to bias or skew the results.

Step Three: Make sure your data comes from reliable labs, using state-specific guidelines

Another component to getting the right data with your soil testing is to use a qualified lab. When you’re looking at determining how much nutrients to apply, use information and data collected from your state or your region.

All three of these steps mean that growers can make better decisions to result in a profit from their investments, and ultimately improve their bottom line.