The Soil is Alive – Updates from University of Kentucky Integrated Plant and Soil Science

 In Modern Farming, Opinion Politics & Science

The Soil Is Alive!

Did you know that a teaspoon of productive soil contains between 100 million and 1 billion bacteria? That adds up to equal the weight of two cows per acre! When you look down, you don’t see them, so they are easy to forget about. However, when you look down and see plants growing you have billions of microorganisms to thank! These microbes are vital in nutrient cycling and many other important processes taking place in the soil.

what's in a handful of soil

How Microbes Are Running My Master’s Degree

As I discussed in my earlier blog post, I am currently a graduate student at the University of Kentucky studying nutrient management in soil science. For my research I am conducting a laboratory incubation study comparing different types of poultry litter and the factors influencing the nutrient content of these manures. During my time at the University of Kentucky I took an in-depth soil microbiology class with a lab that opened my eyes to the importance of these organisms in agriculture. Soil microbiology is also a big part of my research.  I am in the middle of the first study and am currently processing samples as they finish incubating. The reason an incubation process is used is to facilitate microbial activity in the sample cups. These microbes are the ones doing the work to break down the poultry manure and transform the nitrogen into a usable form for plants to use. To create optimal conditions for microbial growth, the sample cups I prepare are kept at about 77°F and the soil is kept at about 50% of field capacity (that is a scientific term that pretty much means the soil is moist but will still crumble in your hand). This is important because it gives the microbes enough water but also allows for air to get to them. They are living organisms, so they need oxygen and water just like us. Over time I take out samples and analyze them for inorganic nitrogen content. I am specifically interested in ammonium (NH4+) and nitrate (NO3) in the soil that the microbes are releasing. This is done by extracting the nutrients from the soil with potassium chloride (KCl), filtering the samples, and then analyzing with flow injection analysis. Once two months of samples are collected, I will have a record of how much nitrogen was released and when it was released.

assembling sample cups with manure and soil            sample cups in the incubator

Goals of the First Study

This first study focuses on two main factors; the rate of manure (poultry, specifically broiler litter) applied and the method the manure is applied. Half of the cups received manure at a rate of 100 lbs of plant available nitrogen while the other half received 400 lbs of plant available nitrogen. This comparison will shed light on differences in the rate of nitrogen release as you increase the amount of manure applied. This study is also comparing a tilled and no-till manure application. For this comparison I mixed the manure into one cup and in an identical cup, I sprinkled the manure on top of the soil. This study is a chance for me to perfect my procedures and techniques before I begin the bigger study that will compare eight types of poultry litter from all around the country.

The end goal of my project is to collect data that will help crop producers improve their decision-making when considering using poultry manure. I am excited to see the results and will be sure to have an update post once I have the results of this first study!


Lydia Fitzgerald

About Lydia

Lydia is a graduate student studying plant and soil science at the University of Kentucky. Her project focuses on soil nutrient management and poultry manure use. Growing up on a farm in Nelson County, VA Lydia helped raise wholesale pumpkins, apples, corn, and soybeans. Her experience includes working in food safety certification.  She started a retail sector with pumpkins, gourds, sunflowers, Indian corn, and sweet corn for a pick-your-own operation. Lydia enjoys home vegetable gardening and loves to learn about different management and marketing strategies for small scale production systems.


If you want to learn more about the living soil and the microorganisms beneath your feet, check out these websites!

USDA NRCS Soil Health

USDA SARE The Living Soil

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