“Fertilizers” - The steroids for growing plants.

To grow, plants need sunlight, water from rain, CO2 for the air, and nutrients [1]. Where do the nutrients come from?

Nutrients include elements like nitrogen, phosphorous and potassium, that plants need to make parts of their bodies [13]. For example, there is lots of nitrogen in protein [14]. Humans need these nutrients too, but we use them for slightly different things [15].

Plants absorb water and nutrients through their roots [2]. If there are not enough nutrients, the plants struggle to grow [4]. When the crops are harvested, the nutrients remain in the plant and are gone from the soil. That’s why we use fertilizers [8] – to make the soil ‘fertile’ again [5]. They are simply a mixture of nutrients that are applied to fields to replenish the missing nutrients [6].

Unfortunately, fertilizers also pollute rivers [9], and are a source of greenhouse gases [7]. But no, we should not stop using them. They’re really useful to help grow enough food for everyone, in combination with changes to farming practices [16]. Whilst some farmers could benefit from being able to buy more fertilizers, they are also often used unnecessarily [16,20]. When they are used, problems can be limited by only applying as much fertilizer as the plants will take up, so there’s little excess in the soil [10,11]. A project in China recently managed to reduce fertilizer use by ~15% whilst also increasing yields [12]! This was done by teaching 20.9 million farmers how and when to plant their crops and use fertilizer [12].

There are alternatives to fertilizer though! For example, plants called legumes (e.g. peas) hold bacteria in their roots [18]. These bacteria take nitrogen from the air, which is then taken up by the plant and made into proteins [18]. The legumes can then be ploughed into the soil and left to break down, releasing nitrogen into the soil, where it can be taken up by crops the next year [17]. Scientists are also trying to genetically modify other crops, like wheat, so that they can also use bacteria to get extra nitrogen [19]. This would be a huge step forward and reduce the need for artificial fertilizers [19].


[1] http://www.co.brown.wi.us/i_brown/d/uw_extension/plant_needs_6-22-2010.pdf

[2] https://www.dummies.com/education/science/how-plants-get-water-and-nutrients/

[3] https://www.sciencedirect.com/science/article/pii/S0889157516302113

[4] https://link.springer.com/chapter/10.1007/978-3-319-10635-9_8

[5] https://www.nationalgeographic.org/encyclopedia/fertility/

[6] http://utbfc.utk.edu/Content%20Folders/Forages/Fertilization/Publications/PB1637.pdf

[7] https://www.sciencenews.org/article/fertilizer-produces-far-more-greenhouse-gas-expected

[8] https://soilsmatter.wordpress.com/2015/03/18/why-do-farmers-use-fertilizers/

[9] https://www.wri.org/our-work/project/eutrophication-and-hypoxia/sources-eutrophication

[10] https://link.springer.com/article/10.1023/A:1025593121839

[11] https://www.canr.msu.edu/resources/management_of_nitrogen_fertilizer_to_reduce_nitrous_oxide_emissions_from_fi

[12] https://www.nature.com/articles/nature25785

[13] https://www.planetnatural.com/fertilizer-numbers/

[14] https://www.cropnutrition.com/efu-nitrogen

[15] https://nutrientsforlife.org/10-ways-soil-nutrients-are-similar-to-human-nutrients/

[16] https://www.sciencedirect.com/science/article/pii/S1877705812045110

[17] https://phys.org/news/2010-03-legumes-nitrogen-fertilizer.html#targetText=Legumes%2C%20with%20the%20proper%20soil,plant%20residue%20%2D%20shoots%20and%20roots.

[18] https://www.nature.com/scitable/knowledge/library/biological-nitrogen-fixation-23570419/

[19] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6095057/

[20] https://link.springer.com/article/10.1007/BF02441403

[21] https://www.chemguide.co.uk/organicprops/aminoacids/dna1.html

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