Day 2: Soil
In nearly all of our landscapes, the soil is the foundation for the biotic communities we encounter. Even on bare rock, the first step in ecological succession is the formation of bits of soil, for instance from the breakdown of rocks by lichen and microorganisms, and from the collection and rotting of falling detritus.
The scientific journal Nature, in addition to their primary scientific literature, produces a range of educational articles by experts—here is the one for soils:
Reading: “What Are Soils? (Needelman 2013)”
Soils are often divided into classes based on texture and associated properties. Here is an introduction to how to tell where your soil falls on the continuum of soil types. It is presented for the benefit of gardeners, but is one of the most useful videos available for naturalists too, because of the ease with which these tests can be performed, with just a jar and access to water.
Video: “3 Free Ways to Determine Your Soil Type (Epic Gardening)” (3:39)
The US Natural Resources Conservation Service has developed a free online service where you can find detailed soil maps of the places you live or explore. Go to the site here and try it out: https://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx
One way in which soils interact with their associated biotic community is through nutrient levels and pH (acidity-alkalinity). All plants have a particular set of requirements and preferences for certain nutrients and pH levels, and so the plant communities we observe will be predictable to some extent by the soil. We will not specifically be doing any soil testing in this course, but pH and nutrient tests can easily be performed with easily available kits at garden stores and online shops.
Pay attention to the soils underlying the ecosystems you visit today. Perhaps test them, either casually by just handling them, or by the methods introduced in the video above. Notice that in soils of different colors or at different levels of moisture and texture have different plants above them, and different fungi and small animals living on and in them. Think of the plant communities you are observing during this course as the produce of the soil, and, in a cycle of time, the decaying matter that returns and forms the soil again.