Fertilizers, Good or Evil?

Hey Foodies! With the huge expansion of agriculture in the 21st century, the use of fertilizers has become more prevalent to produce crops of higher yield to meet the global demand. As such, fertilizer usage has seen a global rise in popularity (Quinn, 2020), resulting in greater levels of water and soil pollution.  

 

Mechanism of Fertilizers:

Let me start off with the properties of fertilizers, their functions, and their problems. Fertilizers used in agriculture often contain active nitrogen and phosphorus, two key nutrients to boost a crop’s growth, as crops absorb these nutrients to grow (Hill, 2010). As such, most fertilizers provide phosphorus, which plays a critical role in helping the plants photosynthesize, resulting in higher nutrients and better health for plants.

As such, the improvement in the growth of the plants and higher yields becomes very tempting for many farmers to make use of fertilizers for agriculture. However, although controlled uses of fertilizers is beneficial to providing a better environment for plants to grow, pollution becomes apparent when these fertilizers are overused.

As such, when we look into the ways that fertilizers can contribute to pollution,  two main forms of pollution pops up, Soil and Water Pollution. Let us investigate further into each form of pollution.

 

Soil Pollution

Soil pollution occurs due to fertilizers when the pH of the soil decreases through the process of nitrification. This process begins with the reaction of ammonia found in the fertilizers with oxygen, with the help of bacteria. Thus, this can form Hydrogen ions which seek to acidify the soil (Hill, 2010).

Also, as pH decreases, the level of heavy metal ions, such as aluminum, manganese, and zinc increases as these heavy metals ions are more soluble in acidic conditions. As a result, these heavy metal ions seek to become inhibitors against the plant’s root system’s ability to absorb the required phosphorus for nutrients for the growth of the plant. Furthermore, these impacts on plant growth can also limit root growth, which leads to a cycle in which the plants become increasingly unable to absorb nutrients and water from deeper areas of the earth (Zhang, 2017). Therefore, causing the problem with infertility of soil in the future.

Thus, Soil pollution provides us a clear explanation as to how it can impact the soil, restricting future growth of vegetation and reducing the efficiency of the land itself. However, Soil Pollution is one of many impacts of fertilizer, and another major part of fertilizer pollution is water pollution.

Water Pollution

Fertilizer also causes problems for water pollution as it is a form of diffuse pollution. As such, the impacts of fertilizers can be much further away, as nutrients from the fertilizers get washed off and into bodies of water. As such, this large influx of nutrients into these water bodies can lead to a process called Eutrophication – a process we will cover in-depth in a future blog post. 

Eutrophication is a process where a large amount of organic matter – in this case, from the fertilizer, are discharged into a water body, which results in high concentrations of plant life. As such, these algae blooms cause a large decrease in water quality, where water in these water bodies becomes increasingly toxic and unsuitable for consumption and activities. Furthermore, the introduction of phosphorus and nitrates from the fertilizers further accelerate this process of eutrophication, causing damage to the ecosystems as the original ecosystems become unable to compete against these fast-growing algae. (Hill, 2010)

As a result, the use of fertilizers can cause problems far away from its source. These chemicals not only cause problems for exposed bodies of water but also groundwater sources, which can cause further impacts on water quality for human consumption. Thus, posing a risk to human health, especially when directly consumed (Peña-Haro et al., 2010).

 

Conclusion:

In conclusion, we discussed the various mechanics of fertilizers and how it impacts the environment as two main sources of pollution, air, and water pollution. However, it is important to note that learning how fertilizers cause pollution is only a part of the puzzle and that we have to understand anthropological factors in play that causes and further aggravate the problem. Also, it is important to take a look at various strategies put into play to reduce the impact of fertilizers on the environment. Thus, that will be in our next blog post! See you soon!

 

Food Detective Out,

Wen Hong

 

References:

Hill, M. K. (2010). Understanding environmental pollution (3rd ed.). Cambridge University Press.

Peña-Haro, S., Llopis-Albert, C., Pulido-Velazquez, M., & Pulido-Velazquez, D. (2010). Fertilizer standards for controlling groundwater nitrate pollution from agriculture: El salobral-los llanos case study, Spain. Journal of Hydrology, 392(3-4), 174-187. https://doi.org/10.1016/j.jhydrol.2010.08.006

Quinn, R. (2020). Global fertilizer demand is bright. DTN Progressive Farmer. https://www.dtnpf.com/agriculture/web/ag/crops/article/2020/01/03/global-fertilizer-demand-bright

Zhang, H. L. (2017). Cause and effects of soil acidity. OSU Extension – Oklahoma State University. https://extension.okstate.edu/fact-sheets/cause-and-effects-of-soil-acidity.html