Case Study: But What About Fertilizers?
Chemical Fertilizers
Chemical fertilizers, also called synthetic or inorganic fertilizers, are made mainly of petroleum or rock, although some of them may have organic matter as well. Usually chemicals are refined to produce a fertilizer that is highly concentrated. There are advantages of using chemical fertilizers: the nutrients are readily available, these fertilizers have the exact ratio of major nutrients (nitrogen - N, potassium - K, and phosphorus - P) needed for plants, and fertilizers are usually easy to use. However, as mentioned previously, there are many disadvantages including soil and water pollution.Organic Fertilizers
To reduce these impacts, many farmers are using alternatives, usually called organic fertilizers. These products are only minimally processed and the nutrients are in their natural form. Manure and compost are among the most well-known types of organic fertilizers. Composts are made from food waste, organic litter, and other garden waste, while manure originates from animal waste. The main differences between organic and inorganic fertilizers are that 1. organic fertilizers contain a greater amount of organic matter, which helps retain water and nutrients in the soil and reduce erosion; 2. breakdown of the organic matter is slower meaning that nutrients are released over time; and 3. there is no or little risk of toxic accumulation as organic fertilizers are biodegradable and more environmentally friendly. The only challenge with organic fertilizers is that microorganisms are needed in the soil to break down the organic matter, and therefore the soil must be warm and moist in order for the microorganisms to do their job.Agrominerals
Another type of naturally occurring fertilizer is agrominerals. Agrominerals are found across the world. They are naturally occurring rocks and minerals that contain beneficial plant nutrients and can be used to enhance the nutrient content in soil. They are composed of similar primary beneficial elements found in most fertilizers - K and P (derived from potassium salts and phosphorus-containing rocks, respectively) - in combination with silicates and carbonate rocks such as limestone or dolostone. These soil amendments can include but are not limited to: clays (containing phyllosilicates that improve water and nutrient retention), zeolites (play a role in ion exchange within the soil), and volcanic materials (provide micronutrients depending on the minerals present).In northern Ontario, a deposit of the agromineral carbonatite is found in the Spanish River. This deposit is thought to be the result of a 1.7-1.0 Ga magmatism event that occurred within the Superior Province and the solidified magma was deposited along structural zones of the Earth. Carbonatite is mostly composed of apatite (source of phosphorus), biotite (clay mineral, rich in potassium), and calcite (reduces soil acidification). Phosphorus is important in root development as well as the composition of plant DNA and RNA, and potassium is required for enzyme activation and withstanding extreme temperatures or droughts. Nutrients contained in the Spanish River carbonatite are integrated into the soil through the physical and biological weathering of the carbonatite itself. Currently, carbonatite is sold mostly as a liming agent to increase the soil pH, but recent research by Brock University and Wilfred Laurier shows that it may be a good product as a fertilizer as well.
