Local agriculture plays a vital part in creating a happy, healthy and self-supporting sustainable community. Unfortunately, the current methods of agriculture, including monoculture and factory farms, can have a heavy impact on our water.
Fertilizers and Pesticides
Due to increasingly intense pressure in the agricultural sector, many farmers use high levels of pesticides and herbicides to repel pests and insects from crops. Fertilizers are also used to keep the land productive year after year. These fertilizers contain the nutrients nitrogen and phosphorus, which improve growing conditions but have negative impacts on water quality.
When precipitation occurs, the rainwater or melting snow flows through the soil and picks up nutrients. As it moves, it carries the nutrients down to the nearest water body, such as a stream or an underground aquifer. This water is known as surface runoff. When dissolved in water, nitrogen and phosphorus act to promote vegetation growth just as they do in the soil. As a result, plankton and algae grow more rapidly. This is referred to as an algae bloom. The algae and plankton thrive for a short time. Whilst thriving they block the needed sunlight for larger plants below. When the blooms die they begin decomposing, a process which uses dissolved oxygen. This decreases the amount of available oxygen in the water. Other aquatic organisms, such as fish and invertebrates, need oxygen to breath; algae blooms, followed by their death and decomposition, causes suffocation of other aquatic organisms. This phenomenon is known as a fish kill. The state of low oxygen levels in the water is called anoxia.
Another fertilizer often used on the farm is animal manure. When used on fields nearby water is at risk of contamination chemicals contained in the manure can be washed into the water; can enter with soil through erosion, or can leak from storage facilities. When manure enters water the nitrogen and phosphorus contained in the manure create algae blooms (see above). Furthermore, manure can contain pathogens such as E. Coli, which can make the water undrinkable to people and animals. It is sprayed on the fields and can enter the water. It can cause reduced oxygen concentrations and introduces antibiotics and parasites into the water if present in the manure. Large sewage lagoons, which hold the enormous amount of animal manure not sprayed on the fields, sit for years. They often leak, and the sewage finds its way into our water supply.
The problem of erosion is also associated with farming. Agricultural practices create loose soil that can get carried away with wind or surface runoff. These are particularly harmful if there is water nearby. The soil erosion leads to sedimentation in the water. Increases in sediment in the water can clog fish gills, preventing proper breathing. It can also bury fish eggs and stop them from hatching. In serious cases of sedimentation, the increase in turbidity decreases the amount of light that can penetrate the water and causes great harm to the aquatic life that depends on sunlight. As was said above, too much erosion can also cause the entry of fertilizers into the water.
There are no simple solutions to the wide ranging and deeply embedded problem of agricultural fertilization practices. One possible solution is organic farming; it does not use pesticides, synthetic fertilizers or animal antibiotics. Still, only a small portion of Ontario's 60,000 farms incorporate organic farming practices. Pesticide use is decreasing by 3% every year due to the increased amount of Genetically Modified Food Organisms (GMO's). However, many scientists are becoming increasingly concerned with the impacts of GMO's, so this may not be the solution. The best thing we can do for our local water bodies is to decrease the amount of pesticides and nutrients flowing into the water by reducing the amount sprayed on the land.