Today was an exciting day in APES. We continued out discussion on by far the most exciting topic in the book, soil degradation and conservation! Now, before accusing me of being uneccesarily sarcastic, let’s look at why soil degradation and conservation is such an important topic.
First, we did a quick review of soil horizons/layers and nutrient leaching. Remember- “O” layer = leaf litter, “A” layer = topsoil. This will come into play shortly, I promise. Stay with me.
There are five ways to degrade soils, both naturally and unnatually: erosion, desertification, salinization, waterlogging, and decreased fertility. Humans have a part in all five of these issues, but erosion is by far the most pressing issue regarding soil degradation for two main reasons:
1. The topsoil level (A-layer, remember?) takes centuries to form an acceptable layer to support plant life.
2. Over 80% of our food supply is dependent on topsoil, and that’s not even counting the meat products we consume that depend on plants.
What causes erosion? Two main natural factors: Wind and Water.
Water is the largest eroder of the topsoil and with it come numerous other environmental effects, such as runoff and sediment pollution in bodies of water.
Then the humans come into play. Through agriculture, farmers have tilled soil to it’s death. The act of tilling and ploweing has churned up the topsoil layer, allowing the particle to become loose and more likely to be degraded by the two natural factors, wind and water.
What can we do to decrease soil erosion?
Farmers: practice low or no till farming methods and lessen soil exposure.
Educationally: the government soil conservation program (NRCS).
Governments: provide susbsidies to keep farmers from planting on erodible land.
The following is a short and somewhat unintentionally hilarious video clip about how farmers can decrease soil erosion.
Ways to control erosion:
Contour planting and strip cropping