The use of pesticides and fertilizers in commercial and industrial agriculture has both it’s benefits and drawbacks.
In this guide, we look at what the potential list of pros and cons might be.
*Note – we are mainly assessing synthetic pesticides and fertilizers used in large scale agriculture in this guide. Natural pest control methods and organic fertilizers, used in more sustainable or organic farming practices, may also have their own specific list of pros and cons
Summary – Pros & Cons Of Pesticides & Fertilizers
Pros
Fertilizers Help Significantly Increase Agricultural Yield
Pesticides Simultaneously Protect Agricultural Goods, Help Deliver A Higher Quality Product, & Increase Production/Yield
Can Help Use Some Resources More Sustainably
Help Meet Demand Of A Growing Population
Contribute To Economic Growth & Other Economic Benefits
It’s Possible That Some Crops May Provide A Carbon Sink For The Potential Emissions From Fertilizer Application
Cons
There’s Various Ways Pesticides Might Impact Human Health
There’s Various Environmental Issues That Pesticides & Fertilizers Might Contribute To
The Use Of Fertilizer & Pesticide Has Potential Sustainable Resource Management Concerns
Pesticides & Fertilizers Can Negatively Impact Animals, Wildlife & Biodiversity
In Some Instances, Pesticides & Fertilizers May Contribute To Economic Loss
Fertilizers & Pesticides May Contribute To, Or Mask The Effects Topsoil Loss & Land Degradation
Subsidies For Pesticides Or Fertilizers May Contribute To Some Problems
Built Up Pesticide Resistance Can Compound Issues
Too Much Fertilizer Application Can Impact Soil Fertility Factors
Pesticides Use Can Sometimes Result In Pesticide Resistant Pests & Super Weeds Developing
Overall
Pesticide and fertilizer use has tradeoffs.
On one hand, there’s a solid argument to be made that the human population either couldn’t be fed effectively, or wouldn’t have the quality of life or scale of agricultural production without pesticides and fertilizers.
On the other hand, pesticides and fertilizers can potentially have a clear negative impact on humans, wild life, the environment, the sustainable use of resources, and other areas of society.
It might be accurate to say that the use of pesticides and fertilizers might be a crucial component of assessing whether current agricultural practices will be sustainable going into the future.
The use of both pesticides and fertilizers has increased over the last few decades.
What Are Pesticides & Fertilizers?
Pesticides are usually a chemical or biological agent (in the case of some natural pest control methods) used to kill, repel or control a specific pest against damaging an agricultural good (such as crops or livestock) or spreading disease.
Fertilizers are usually a substance or chemical mix added to soil/land, to supply crops/plants nutrients (can be macronutrients and also micronutrients), and they can also help increase soil fertility
Types Of Pesticides & Fertilizers
Synthetic vs Natural
Firstly, there’s a difference between synthetic pesticides and fertilizers, and naturally derived ones.
A synthetic pesticide might be made from specific man made chemicals, where as natural pest control can involve methods like IPM.
A synthetic fertilizer can be made from fossil fuels and man made chemicals, whereas natural fertilizers might include substances or organic matter like manure, compost and food scraps, and so on.
Other Types
Secondly, both pesticides and fertilizers can be broken down into their individual types.
Pesticides can be broken down into the type of pest they target – insecticides, herbicides and fungicides being just a few examples (although herbicides are the most common – they make up about 80% of all pesticide use)
They can also be broken down by their chemical profile (or chemical family), or brand – glyphosate and Roundup being an example.
Fertilizers are often broken down by being a nitrogen, phosphorus, or potash fertilizer.
There’s also other ways to break them down such as solid fertilizers, liquid fertilizers, slow release fertilizers, specialty fertilizers, and so on.
Potential Pros Of Pesticides & Fertilizers
Fertilizers Help Significantly Increase Agricultural Yield
A main function of fertilizers is to supply nutrients (macro and sometimes micro) that crops can absorb through the soil.
This can help crops achieve more ideal growth, and usually increases yield compared to if fertilizers aren’t used.
This might especially be useful in modern times with topsoil levels being degraded in several countries due to intensive farming practices, and wind and water erosion.
Fertilizers can be used on crops that will be directly consumed by humans, but also for growth and better yields for animal feed
Without nitrogen fertilizers, scientists estimate that we would lose up to one third of the crops we rely on for food and other types of agriculture (kids.frontiersin.org)
[The use of synthetic fertilizers starting in the 19th century was] important in transforming the global food system, allowing for larger-scale industrial agriculture with large crop yields (wikipedia.org)
In the later half of the 20th century, increased use of nitrogen fertilizers (800% increase between 1961 and 2019) have been a crucial component of the increased productivity of conventional food systems (more than 30% per capita) (wikipedia.org)
Conservative estimates report 30 to 50% of crop yields are attributed to natural or synthetic commercial fertilizers (wikipedia.org)
Nitrogen [found in nitrogen based fertilizer] is essential for the development of all plant organs including shoots, buds, leaves, roots, and bolls (ipni.net)
Pesticides Simultaneously Protect Agricultural Goods, Help Deliver A Higher Quality Product, & Increase Production/Yield
The core function of pesticides is to target pest species to control them against damaging an agricultural good like crops.
By doing this, agricultural goods are protected (from weeds, fungi, insects, etc), they are able to maintain a higher quality for market, and there is a higher yield and productivity because more of the goods are available compared to if a certain % were damaged by pests.
This may be observed in organic cotton crops as one example, with some reports indicating that reduced use of pesticides may result in lower yields.
They can also increase the number of times per year a crop can be grown on the same land.
Can Help Use Some Resources More Sustainably
Something that is not often considered is that increased yield/productivity leads to more efficient use of some resources used in agriculture.
One example of this is land – farmers can get more production/yield from the same square area of land.
Help Meet Demand Of A Growing Population
The world’s population has been growing in recent history.
Because fertilizers and pesticides allow for greater yield and productivity, they are a key component in being able to meet the food demand (and other agricultural product demands) of this growing population now and in the future.
… it has been estimated that almost half the people on the Earth are currently fed as a result of synthetic nitrogen fertilizer use (wikipedia.org)
Contribute To Economic Growth & Other Economic Benefits
Agriculture is one of the main industries in the world.
Increased production due to the use of fertilizers and pesticides has helped agriculture better contribute to the economy, and some of the side effects have been employment and income for society, helping farmers save money, and helping stabilize food prices.
The pesticide industry alone is estimated to be worth hundreds of billions of dollars worldwide.
One studied mentioned by wikipedia.org outlines that the health and environmental cost of pesticides in the US is offset by the increased agricultural production that pesticides provide
… nitrogen fertilizer use supports California’s robust agricultural economy and rural society (calag.ucanr.edu)
… in the U.S., farmers get an estimated fourfold return on money they spend on pesticides … [and pesticides can have a positive effect on food prices, jobs, and world hunger] (wikipedia.org)
Some Crops May Provide A Carbon Sink From Any Greenhouse Gas Emissions From Fertilizers
One potential example of this is cotton crops …
Supporters of cotton though say that cotton lint provides a cotton sink for some of this nitrogen and nitrous oxide emission (slate.com)
Potential Cons Of Pesticides & Fertilizers
There’s Various Ways Pesticides Might Impact Human Health (Potential Toxicity)
At the farm level, farm workers and those in the near vicinity of where pesticides are used can be exposed to pesticide, through direct contact with skin, or inhaling pesticide in the air.
This may be more of a problem in low and middle income countries (who.int), and wikipedia.org also suggests that most pesticide related deaths occur in developing countries
At the consumer level, pesticide can get into/on food as pesticide residue, and can even get into the water supply.
Although, some sources say that pesticides aren’t as much of a risk at the consumer level because the levels of pesticides aren’t high enough.
The exception to this might be more vulnerable groups like children and infants, and pregnant women.
It’s worth noting that regulations or standards relating to pesticide use can differ between countries. The risk of of pesticide use might be lowered by following safer regulations and standards that outline lower risk pesticides and pesticide levels to use.
Some countries might have regulations with shortcomings regarding health and safety. International trade can also see foods produced under one set of regulations be exported to another country with another set of regulations.
As who.int describes, different pesticides have different functions, chemical makeups, and other variables that impact their profile. Dosage amounts, route of exposure, and other factors can all play a part in how a pesticide might impact human health.
ewg.org also goes into more detail about specific pesticides and types of pesticides, and describes their potential effect on human health.
wikipedia.org mentions that the quicker a pesticide degrades in the environment, the quicker it might lose it’s toxicity
Pesticides have been linked to public health effects …
Nitrogen fertilizer … and circulation of reactive nitrogen can have negative effects on … human health
[Both pesticides and fertilizers can get into water sources]
– journals.plos.org
There’s Various Environmental Issues That Pesticides & Fertilizers Might Contribute To
Just a few examples of environmental issues might include water pollution, air pollution, GHG emissions, and more.
Additionally, fertilizers require methane/natural gas to make, and there are the indirect environmental issues caused by natural gas drilling and fracking to consider.
Applying nitrogen in excess has been linked to water and air pollution, depletion of the ozone layer, climate change and numerous human health concerns (calag.ucanr.edu).
You can see a good diagram showing the impact of the nitrogen cycle in the calag.ucanr.edu resource.
In Australia … nitrous oxide emissions have increased 130 percent since 1990 due to fertilizer usage …
When these fertilizers are applied haphazardly, large amounts of nitrous oxide—which has a GWP (global warming potential) of 310—can be lost to the atmosphere
– slate.com
The Use Of Fertilizer & Pesticide Has Potential Sustainable Resource Management (& Resource Depletion) Concerns
We put together a guide of whether we might be running out of phosphorus, nitrogen, and other minerals/elements used in fertilizers here.
Secondly, a portion of nitrogen fertilizers can either be washed away (particularly in areas with heavier rainfall), or can convert into nitrous oxide, before they can take affect on the crops they are applied to. When there is consideration for the resources that go into making nitrogen fertilizer, some question the sustainability of it from a resource management perspective
news.mongabay.com discusses reactive nitrogen and phosphorus in the biosphere in deeper detail in their guide, and they also discuss how some fertiliser nutrients like nitrogen are lost to crops when applied
In Australia … it’s estimated that a third of the nitrogen applied to cultivated fields is lost before serving any purpose (slate.com)
Pesticides & Fertilizers Can Negatively Impact Animals, Wildlife & Biodiversity (Potential Toxicity)
This impact can be direct, such as when wildlife come into contact with/are exposed to some types of pesticide chemicals
Or, there can be more of an indirect impact where fertilizers may contribute to nutrient pollution in water bodies that aquatic species live in.
Sometimes the impact can be pesticide specific – for example, some sources indicate DDT was a problem pesticide in the past, but it has since been banned in some countries.
Atrazine may be a specific herbicide that may cause issues in some mammals.
Pesticides … nitrogen fertilizers … and phosphorus fertilizers … [have been linked to negative impacts on wildlife]
[Pesticides have also been linked to pesticide resistance in target pest species]
– journals.plos.org
Pesticide exposure [in the form of direct spray exposure, or consuming animals that have been exposed to pesticides] can be linked to [a range of effects] in a wide range of species.
Wildlife can be impacted by pesticides through their direct or indirect application, such as pesticide drift, secondary poisoning, runoff into local water bodies, or groundwater contamination.
– beyondpesticides.org
Atrazine is a herbicide [can cause] problems in mammals, amphibians and fish that have been exposed.
Pesticides and herbicides can cause toxicity to non target species like bees and other non target species
– wikipedia.org
In addition to killing insects or weeds, pesticides can be toxic to a host of other organisms including birds, fish, beneficial insects, and non-target plants. Insecticides are generally the most acutely toxic class of pesticides, but herbicides can also pose risks to non-target organisms (ncbi.nlm.nih.gov)
Paraphrased from wikipedia.org – [Although, with pesticides specifically, the impact of a pesticide might depend on the chemical family the pesticide belongs too – DDT was found to have links to impacting the health of wildlife, but it’s been banned in several developed countries (such as in the US in 1972)]
In Some Instances, Pesticides & Fertilizers May Contribute To Economic Loss
Pesticides may have an economic impact on wildlife to consider (some estimates say this runs into the billions)
And, if pesticides and fertilizers contribute to environmental pollution or other environmental issues, there’s the hidden upfront cost of how much clean up (say for example of a polluted water body), or addressing other environmental issues might cost.
Some of these costs may be difficult to accurately estimate.
Fertilizers & Pesticides May Contribute To, Or Mask The Effects Topsoil Loss & Land Degradation
Fertilizers and pesticides may be a contributing factor to some types of land and soil degradation.
They may also mask some of the long term effects of these problems, such as declining yield and land productivity.
Subsidies For Pesticides Or Fertilizers May Contribute To Some Problems
In some countries, subsidies for pesticides and fertilizers may lead to artificially pushing up demand, or, giving incentive to buyers to not use pesticides and fertilizers as effectively as they could.
These things can create a flow on effect of contributing to problems outlined elsewhere in this guide.
Having said this, some countries are in the process of decreasing pesticide or fertilizer subsidies.
Built Up Pesticide Resistance Can Compound Certain Issues
It’s possible that over time, certain crops can build up more of a pesticide resistance to certain types of pesticides.
What this means is that more pesticide chemicals have to be used.
This can compound certain problems that pesticide chemicals already contribute to
Too Much Fertilizer Application Can Impact Soil Fertility Factors
As just one example, when the soil receives too much of a certain nutrient from fertilizer, it can impede crops and plants being able to absorb other nutrients.
Applying fertilizer requires the right balance.
Pesticides Use Can Sometimes Result In Pesticide Resistant Pests & Weeds Developing
Synthetic pesticides can in some instances cause pesticide resistant pests, or super weeds to develop (that can take over other plant species in the area) after consistent or repeated exposure to the synthetic chemicals.
Secondary pests may also develop too.
Stages At Which Pesticides & Fertilizers Might Impact Society
1. Manufacturing stage – energy and other resources used
2. Use of pesticides and fertilizers on farms – some pesticides and fertilizers can be lost before they take effect (such as fertilizers washing away), leaching into soil and water, air emissions, impact on wildlife, impact on humans, and so on
3. Consumer stage – pesticide residue found on food
Is Synthetic Pesticide & Fertilizer Use Increasing Or Decreasing?
The use of both seems to be increasing.
Pesticides
… pesticide use has increased 50-fold since 1950 [where between 1940 and 1950 is considered to be the start of the ‘pesticide era’ in the US] … [and] Seventy-five percent of all pesticides in the world are used in developed countries, but use in developing countries is increasing (wikipedia.org)
Fertilizers
The use of synthetic nitrogen fertilizers has increased steadily in the last 50 years, rising almost 20-fold to the current rate … (wikipedia.org)
The use of phosphate fertilizers has also increased from 9 million tonnes per year in 1960 to 40 million tonnes per year in 2000 (wikipedia.org)
Other Notes On Pesticides & Fertilizers
Alternate farming methods, the use of biological pest control, the use of pest resistant engineered GMO crops, and selective insect breeding can all lead to the decrease in use of synthetic pesticides.
The pros and cons of synthetic vs natural fertilizers can obviously be very different to one another
Some crops like legumes have the ability to fix nitrogen from the atmosphere, so may not need nitrogen fertilizer
Sources
1. Rosenstock T, Liptzin D, Six J, Tomich T. 2013. Nitrogen fertilizer use in California: Assessing the data, trends and a way forward. Calif Agr 67(1):68-79. – http://calag.ucanr.edu/Archive/?article=ca.E.v067n01p68
2. Aktar, Md Wasim et al. “Impact of pesticides use in agriculture: their benefits and hazards” Interdisciplinary toxicology vol. 2,1 (2009): 1-12. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2984095/
3. https://www.ewg.org/foodnews/summary.php
4. Conrad, Z., Niles, M.T., Neher, D.A., Roy, E.D., Tichenor, N.E. and Jahns, L., 2018. Relationship between food waste, diet quality, and environmental sustainability. PloS one, 13(4), p.e0195405. – https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0195405
5. https://www.who.int/news-room/fact-sheets/detail/pesticide-residues-in-food
6. https://en.wikipedia.org/wiki/Fertilizer
7. https://en.wikipedia.org/wiki/Pesticide
8. https://kids.frontiersin.org/articles/10.3389/frym.2019.00041
9. https://www.seasol.com.au/home-garden/handy-hints/seasol-guide-to-fertilisers/seasols-guide-to-fertilisers/
10. https://slate.com/technology/2008/01/if-i-want-to-help-the-environment-should-i-buy-wool-or-cotton.html
11. https://www.beyondpesticides.org/programs/wildlife
12. https://en.wikipedia.org/wiki/Environmental_impact_of_agriculture
13. https://news.mongabay.com/2021/09/nitrogen-the-environmental-crisis-you-havent-heard-of-yet/
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