In the world of intensive agriculture, the chemical fertiliser reigns supreme. A powerful cocktail of chemically enhanced nutrients designed to adjust soil to suit a desired crop, chemical fertilisers are used to force imperfect land to produce the high yields required for mass export. Yet the long term damage of chemical fertilisers is extensive, impacting the land, local ecosystems, and even health of consumers.
Much of this damage is attributed to the primary ingredients of chemical fertilisers; reactive nitrogen and phosphorus. While their application boosts the health and growth of a crop, oversaturation contaminates groundwater sources, with studies finding that chemical runoff is causing freshwater acidification, and in coastal areas creating algal blooms that soak up the oxygen needed for fish and crustaceans, leaving us with “Marine Dead Zones” around the world[2].
Water pollution isn’t the only risk; whenever chemically fertilised soil is tilled, remaining nitrogen is released into the atmosphere as ammonium nitrate, different (though just as impactful) as the sodium nitrate released by fossil fuels. With this difference allowing agricultural pollution to be tracked, it’s been found that 50% of all atmospheric nitrogen pollution in the US can be attributed to agricultural origins, and higher still at 55% in the EU, with China producing over 65% from agriculture alone[3].
Yet even when it stays in the ground, increased nitrogen and phosphorus levels acidifies the soil (often offset by further use of chemical fertilisers) and leaches into future crops, which release it as ground level ozone. Ozone pollution causes respiratory damage, raising asthma, allergies, and even the risk of blue-baby syndrome, while increasing risk of cancer and chronic diseases from nitrate pollution[1][2].
Agroecology is a collection of agricultural practices where the principles of ecology are applied, focusing on biodiversity and the reduction and prevention of ecological harm. Organic farming, food forests, permaculture and regenerative agriculture are all examples of agroecological methods, with sustainability being at the heart of each practice, but each depends on context-specific knowledge, tailored to a local biosystem, rather than replacing it with an agricultural standard. By doing so, we can support the land we use to grow our crops, and ensure the soil is healthy enough for future generations to continue growing food. Using this model, we can reach harmony with nature without facing a collapse in our food supply.[4]
Yet adjusting to these practices doesn’t mean a loss in food production. Described as “ecological intensification”, adopting agro-ecological methods, along with polycultural crop rotations and reducing the tilling of soil, has been proven to attain similar crop yield levels as intensive agriculture, without chemical fertiliser dependence, and even improved natural soil quality, biodiversity, and natural pest control and disease resilience.[5]
Elements such as growing a ground crop of legumes to produce natural nitrogen, allowing animals to graze on the plot, and composting plant remains and/or manure for natural fertilisation allow existing farms operating at intensive levels to significantly reduce their impact without loss of yield.[4][5]
With humans already having doubled the flow of reactive nitrogen on land[2][3], and having an equal share of atmospheric nitrogen pollution as fossil fuels[3], it’s all the more astonishing that chemical fertilisers were adopted as recently as the 1990s. Even so, we have what we need to grow into our sustainable future, and transform agriculture to support both the land it uses and the people it serves.
[1] https://www.canr.msu.edu/news/what_is_reactive_n_and_why_should_i_care
[2] http://www.millenniumassessment.org/documents/document.356.aspx.pdf
[3] https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL068354
[4] http://www.fao.org/3/I9037EN/i9037en.pdf
[5] https://www.nature.com/articles/s41893-022-00911-x.epdf
Search terms for your own research: Agroecology principals, the nitrogen cycle, chemical fertilisers - a risk to soil life
Urban Forests, Natural Capital Accounting
Monoculture Farming, Greenwashing