Causal Loops

Alex Polnaszek
Fertilizer Composition and Use

Fertilizers have helped farmers and the production of food in this country immensely. They have allowed farmers to have a higher yield of food per acre despite some deteriorating soil conditions. There are three main elements in each bag of fertilizer. They are nitrogen, phosphorus and potassium and are represented on the outside of the bag in that order. Each of the three elements has a different benefit to the growth of a plant. Plants use nitrogen to digest proteins, nucleic acids and hormones. When a plant is lacking in nitrogen, it may have stunted growth and yellowing leaves. Phosphorus is also very important to plant growth. It assists in converting the sun’s energy and other chemicals into usable foot for the plant. A lack of phosphorus can also lead to stunted growth and weak crop production. The last of the three main elements in fertilizer is potassium. Potassium is essential in plants to help them use water and resist drought while enhancing the size of fruits and vegetables. Despite fertilizers being such a benefit to farmers, there are some environmental concerns that come along with it. Runoff from fertilizers often finds its way into water ways. The nitrogen rich runoff can lead to eutrophication in these water ways. The lack of dissolved oxygen in the water leads to cloudy and discolored water along with a void of animal life. Eutrophication is most commonly seen in coastal regions and major steps have been taken recently to try and combat the growing problem.
Sources:
www.epa.gov http://www.ehow.com/about_5434676_effects-fertilizers-pesticides-water-bodies.html http://ezinearticles.com/?About-Plant-Fertilizer-and-Their-Composition&id=269755