Dig It!

Field trip number two involved going to see an exhibit on soil! There is a surprising amount of information about soil that I never even knew existed. For example, every state has a state soil that has properties distinguishable from other soils in the state. In Minnesota, our state soil is called Lester, and used to be forested areas before it was converted to farmland. Now it is a good soil to grow crops on, and mainly supports corn and soybeans. You can see a sample of our state soil on the very left.

 

Earth also has different "skin types," some of which are better suited for agriculture than others. One skin type I learned about expanded well in water, but when dried out could leave crevices almost 3 feet deep.

 

Scientists in the United States are considering adding another skin type to the list of skin types in the United States. This skin would be the result of human intervention.

 

Of course, some of the most interesting facts related directly to agriculture and expanded upon what we learned in class this semester. Plowing disturbs the bacteria, fungi, and other organisms that are a vital part of a healthy soil system. In the 1930's, part of the reason the dust bowl was so bad was because of poor farming practices. The topsoil eroded, leaving behind an infertile area that devastated entire communities. A similar problem is facing Africa today. Farmers in the Sahara have used up the scarce soil nutrients, and did not add nutrients back to the soil through composting or other sustainable practices. The Millennium Villages Project is helping to educate and help farmers to increase their yields and productivity.

 

 

One of the most interesting facts I learned about was that of the terra preta created by South American Indians a very long time ago. Terra preta is essentially a very fertile soil that was created from partially burned areas of the forest. Slash-and-char farming left patches of very fertile soil (which are still around today) in place of highly infertile soil. Researchers are looking for new insights into this practice in order to help farmers today. I thought the practice of burning trees to create nutrients a bit surprising, because burning of the forest to create more farm land is considered to be an unsustainable practice that yields poor soil after just a couple of years. Yet, the Indians were able to make this practice highly successful. With more research, I hope that farmers in the Amazon Basin will able to move away from practices that destroy the soil and create a sustainable source of soil nutrients. Below is a replica of what terra preta looks like.