The Secret World of Soil

This appeared in the October 21, 2021 edition of The Fish Wrap.

What is soil? It seems like a simple thing until you scratch the surface.  The physical characteristics of soil vary greatly around the world, but they all have the same basic building blocks.  Sand, silt and clay have combined in varying ratios to make all the different soil types.  The high quality soils across our region are considered loam, a combination of around 40% sand, 40% silt, and 20% clay. 

Through either the extreme forces of the earth grinding rock, or acidic secretions from microbiology, our earth has been terraformed over billions of years  into an amazing habitat.  Sand particles are large enough that you can easily see and feel them,  ranging from .05mm--2mm in size.  Silt is considered to be from .002mm--.05mm and clay is everything .002mm and smaller.  Silt and clay particles are too small to see without the aid of a microscope, but you can feel the difference.  With a little water added, silt will still be a little gritty rubbed between your fingers, but clay will feel silky smooth.

All of the particles of soil bond with other minerals and nutrients to create more subcategories of soil types.  Different minerals and nutrients create the array of different colors we see in soils.  Smaller particle sizes allow for more bonding sites for minerals and nutrients, which is why clay plays an important role in soil fertility.

Our understanding of soil has been shifting for the last few decades. The previous century was all about chemistry, while the next one will be about biology. The chemistry of soil is amazing and complex, but the magic happens with the synergistic relationship that it has with the microbes that call it home. We need to recognize and respect the microbes that give us life.