Sustainable farming is part of the solution to climate change
Sustainable farming is part of the solution for improving the sustainability of food systems and reducing greenhouse gas emissions. It refrains from using synthetic fertilizers and pesticides, promotes crop rotations and focuses on soil fertility and closed nutrient cycles.
Sustainable farming practices decreased with the advent of the industrial revolution. Industry leaders and government decision-makers leaned on machine-based farming, as well as synthetic fertilizers, pesticides and monocropping to feed their populations. Some of these innovations are incredibly positive. Yet, this has created a practice that not only stripped crops from their ecosystems’ broader dynamic, but also stripped soil of its rich organic matter and diverse microbiomes – two factors that are essential for carbon absorption and a whole host of other climate balancing activities.
Nitrogen cycle
Microorganisms have been controlling Earth's nitrogen cycle since life originated. With life evolving around it, nitrogen became both an essential nutrient and a major regulator of climate.
Without nitrogen, most of the world’s crops wouldn’t exist. Nitrogen is to corn, wheat and rice, what water is to fish. Yearly, more than 100 million tonnes of nitrogen are applied to crops in the form of fertilizer, helping them grow stronger and better (United Nations environment programme). But issues arise when nitrogen run-off occurs, polluting air, water and land in the process. It is estimated that nitrogen discharge accounts for a third of agriculture’s greenhouse gas emissions (United Nations environment programme).
Nitrous oxide has always existed in the atmosphere. As illustrated above, it is produced by microbes in soil and naturally released, especially from tropical rainforests, permafrost melting in the arctic, as well as microbes in oceans.
Nitrous oxide is 300 times more powerful than carbon dioxide as a greenhouse gas. Human-made sources account for an increasingly larger share of nitrous oxide emissions. An estimated one third to one half of the nitrous oxide released into the atmosphere today is a result of human activities (Research Gate). The use of synthetic fertilisers has increased these emissions compared to sustainable practices.
Organic vs synthetic fertilisers
Organic fertilisers are materials derived from plant and animal parts or residues. Examples are, blood meal, compost, bat guano, manure, seaweed, and worm castings.
As detailed by Fertilizer Europe, “the production of nitrogen (N) synthetic fertilisers involves mixing nitrogen from the air with hydrogen from natural gas at high temperature and pressure to create ammonia. Approximately 60% of the natural gas is used as raw material, with the remainder employed to power the synthesis process. The ammonia is used to make nitric acid, with which it is then mixed to produce nitrate fertilizers such as ammonium nitrate (AN). Ammonia may also be mixed with liquid carbon dioxide to create urea. Both these products can be further mixed together with water to form UAN (urea ammonium nitrate) solution”.
Source: Fertilizer Europe
Plants cannot distinguish between an organic or synthetic fertilizer – the nutrients are processed in exactly the same way. However, the similarity stops there.
Chemical fertilizers add nutrients to the soil, but they don’t add anything else. Plants needs more than just nutrients to survive. They also need organic matter and living organisms. Synthetic fertilizers do not support microbiological life in the soil. The application of a synthetic fertilizer can be toxic to beneficial microorganisms. These microbes are responsible for breaking down organic matter into a stable amendment for improving soil quality and fertility. Some convert nitrogen from the air into a plant useable form.
Monocropping vs crop rotation
As defined by Wikipedia, “Monocropping is the practice of growing a single crop year after year on the same land. Maize, soybeans, and wheat are three common crops often monocropped. Monocropping is also referred to as continuous cropping, as in "continuous corn." Monocropping allows for farmers to have consistent crops throughout their entire farm. They can plant only the most profitable crop, use the same seed, pest control, machinery, and growing method on their entire farm, which may increase overall farm profitability”.
Crop rotation is the practice of planting different crops sequentially on the same plot of land to improve soil; health, optimize nutrients in the soil, and combat pest and weed pressure.
For example, if a farmer has planted a field of wheat. When the wheat harvest is finished, they might plant a legume pasture or pulses, since wheat consumes a lot of nitrogen and legumes return nitrogen to the soil.
Pasture and pulse legumes fix nitrogen. They absorb nitrogen from the soil atmosphere into small nodules on their roots and the bacteria (rhizobia) in the nodules convert the atmospheric nitrogen into ammonia (NH3) (GRDC). The ammonia is then converted into organic compounds by the plant and used for growth (GRDC).
A crop rotation can help to manage your soil and fertility, reduce erosion, improve your soil's health, and increase nutrients available for crops.
Carbon sequestration
The California climate and agriculture network noted that properly managed soil has the potential to serve as a carbon “sink” through a process called soil carbon sequestration, in which atmospheric carbon dioxide is converted by photosynthesis in plants to organic forms of carbon and stored in soils. Practices that increase soil organic matter also support carbon sequestration. Building healthy soils that can sequester carbon provides an important opportunity for agriculture to both mitigate and adapt to climate change.
The California climate and agriculture network noted that the most promising practices include planting cover crops, reducing or eliminating tillage, using diversified crop rotations that keep soil covered, improved grazing management, applying organic soil amendments such as compost and manure, and reducing and properly timing the application of nitrogen fertilizer inputs
Though it can take years to build healthy soils, farmers can reap long-term benefits such as improved water penetration and retention, decreased need for chemical inputs, and greater resilience to drought, flooding and pest infestations.
Sustainable farming and acting on climate change
Through the act of pursuing sustainable farming practices, we can contribute to mitigating climate change.
By reducing the use of synthetic nitrogen fertiliser, sustainable farming has the potential to reduce nitrous oxide emissions (a powerful greenhouse gas) .
Sustainable farming promotes soil fertility, increasing the potential for carbon sequestration and mitigation of carbon dioxide in the atmosphere.
As consumers, if we are looking to act on climate change (and improve our own health), we can choose to purchase products that are sustainably farmed. A sustainably farmed product is certified organic or biodynamic.
The farm certification requires:
landscape management and biodiversity - enhancing biodiversity, including retaining native trees
soil management - developing healthy soils
water management - the harvest, storage, use and fate of waters are integral components of an organic farm
plant production - the crops and varieties grown are those best suited to local and regional conditions; the least susceptible to pest and disease; and of a good nutritional and physiological quality
plant protection - implementation of management practices and not using substances to manage pests
livestock nutrition and welfare
