Discussion 7: Soil RehabilitationCourtney Johnson

Describe the techniques that you would use to rehabilitate

soil at an urban site in Boston.

The first thing I would do when creating this urban site soil rehabilitation project would be to analyze the soil and learn about the structure, texture, and the general characteristics. I would then focus on how to improve that soil based upon that analysis. I would add provisions to adjust the pH to a level of 6-7 so the plants could use the maximum amount of resources, add things like bone meal or rock phosphate if the phosphorous level was low, and add substances such as green sand if the potassium levels were too low. I would also introduce some cover crops into the landscape to add to soil fertilization. The cover crops provide good shelter to the soil from the climate in Boston, and further prevents erosion by adding the stability of a root system. They can be cut down before flowering to then decompose and provide nutrients to the soil. There are also some cover crops specifically meant for “drilling” and breaking up the soil. Those are left to decompose so oxygen and nutrients can then be used in the deeper layers of the soil. The broad fork method would also be a good tool for an urban setting. Generally, there will not be room for large scale tilling operations within an urban area, so a broad fork works just as well in a smaller area.

Lesson Learned 1: Scale of Erosion

I did not realize on just how large of a scale soil erosion was occurring on. The figure of over 6 billion tons of topsoil lost every year was completely mind blowing to me. I always read about coast lines eroding away and that always made a lot of sense due to the power of ocean and wind. I had never truly realized just how much soil was lost everywhere due to many, many forces. I learned that it is very important to identify why the soil erosion is occurring on such a large scale in order to create areas/policies that will start to lessen the number of tons of soil lost a year.

Lesson Learned 2: pH Levels Effects

I knew a bit about the idea of soil being more acidic in most places than it should be due to the acid rain that occurred decades ago and the lasting effects of it. What really interested me though was that a lot of nutrients and minerals are only available to plants at a pH of around 6-7. This connection makes sense, as too basic or too acidic soil conditions are not good for growing plants in, but I had never really thought of why that may be besides the acidity/basicness.

Lesson Learned 3: Cover Crops

This lesson really furthered my understanding of cover crops. I had previously known what a cover crop was on a very basic level, but it was interesting to learn about different types of them. I liked how some of them are meant to be cut down to fertilize the top soil, while other are meant to grow deep underground where they will rot and aerate/provide nutrients to the deeper layers of soil. I had previously really thought of them as just a way to stabilize the soil with a root system that would hold it all more in place, but it was very interesting to learn that they have multiple uses depending on the type of cover crop.