If you’re attending school in-person, there’s a high chance you drive by a cornfield or soybean field on your way to school. While no grains are currently growing, you can still see the vast land used to grow these crops. Champaign-Urbana is situated in a unique spot because it’s full of the corn and soybean growth that characterizes much of central Illinois, and home to the University of Illinois Urbana-Champaign, a leading research institute. When these two entities join forces, all can benefit, including the soil that our crops grow on. In May 2020, the U of I released research, which suggested a lower soil mass may improve soil health.
To understand why, you need to dig deep. According to Agvise Labs, Soil is mostly made up of air, water and minerals, with organic matter making up only around 1-5% of the soil’s volume. But this small percentage of organic matter packs a big impact: almost all of a plant's nutritional needs can be met from it. In this case, organic matter contains mostly carbon: a building block for all living creatures. One specific kind of carbon within soil is activated carbon, or POXC, which makes up 1-4% of the total carbon content. Activated carbon differentiates itself from other carbons with its high porosity: its ability to soak up a variety of things, including substances toxic to the crop. Of equal importance is the way POXC only appears in small amounts. The USDA confirms that soil scientists use activated carbon to calculate the amount and quality of organic material within a soil sample. They would then use those findings to estimate the total amount of organic material in any given plot of soil. This makes activated carbon the perfect substance for researchers and growers alike to measure the quality of their soil.
Mirijam Pulleman et. al. from the U of I’s Soils Lab have recently discovered that reducing the grind size (the size of an individual soil granule) makes activated carbon function better as a soil quality indicator. When you decrease soil’s grind size, the population of activated carbon has a comparatively larger surface area to a standard-sized granule of soil. This means that it can absorb nutrients or harmful substances more easily, and take less time to adapt to changes within the soil. So when multiple samples are taken over a period of time, the information gathered from the POXC will be more accurate to the date they were collected, which would then paint a more accurate picture of how well a field is doing.
But while a good understanding of soil health is important for agricultural producers, it’s similarly important information for environmental experts. Because every crop requires a certain variety of nutrients, soil can slowly run out after years of growing a limited variety of crops. Crop rotation and fertilizers are both different methods to restore the nutritional content of the soil, but there’s no gold standard that tells environmental experts how much it will change. But if a researcher were able to have more confidence in a soil sample's composition at a certain time, understanding the effects of factors like fertilizer and crop rotation would be much more simple.
Photos courtesy of Pixabay.