An urgent need for large-scale humus farming and a climate positive agriculture

Azadeh Farajpour-Javazmi, Alumna of Göttingen & Scientific Associate at FAW/n – Research Institute for Applied Knowledge Processing

“The global temperature rise over land masses has already reached 1.53 degrees. If global warming actually rises to two degrees, the livelihoods of up to 500 million people worldwide would be threatened, including by lack of water and the expansion of deserts” [1].

Climate protection is a survival issue for the human civilization, as we know it today. The limits of the earth’s capacity are reached faster and faster. Extreme and sudden changes in climate patterns are already detrimental to the world today. On the other hand, climate change is strongly linked to socioeconomic developments and must not be resolved at the expense of the low-income sections of the societies in rich and poor countries.

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“Land provides the principal basis for human livelihoods and wellbeing including the supply of food, freshwater and multiple other ecosystem services, as well as biodiversity” [1]. Land also plays an important role in the climate system and can sharpen the adverse impacts of climate change. However, it can mitigate and build resilience against climate change. Agriculture plays a very important role in this context. Croplands can either be a net source or be a net sink of anthropogenic greenhouse gas emissions (GHGs). Currently, agriculture contributes to 23% of total anthropogenic GHGs. In addition, the sector is a key area of development cooperation, on which a large part of the population in developing countries depends. On the other hand, a large volume of scientific research shows the enormous capacity of agriculture to reduce GHGs and even act as a greenhouse gas sink. Agriculture therefore has enormous potential for contributing to climate protection, climate adaptation and sustainable development (e.g. SDGs) as a whole.

Depending on how agriculture is operated, GHGs can either be captured or released! Soil humus formation and the use of biochar play a significant role in fixing carbon from CO2 in the soil. Humus is the dark organic matter that forms in soil when dead plant and animal matter decays. Humus has many nutrients that improve the health of soil, among others, nitrogen as the most important one. Humus is essential for soil fertility and can significantly change the properties of soil.

Humus determines how healthy and fertile the soil is. Soil with humus …

  • has a high absorption capacity for water (A soil well supplied with humus can absorb up to 150 litter of water per hour). Humus acts like a sponge and absorbs moisture while releasing water and thus helping soil during dry seasons.
  • has a high storage capacity for water increases (an additional 400 m3 of water per hectare can be stored per 1% increase in humus)
  • Enormous storage capacity for nutrients (1% humus at 30 cm soil depth means a nitrogen pool of an additional 2500 kg per hectare – no additional fertilization is required). In other words, humus holds nutrients in soil and prevents them from leaching and being washed out.
  • makes the production becoming safer and cheaper (The entire tillage and the entire plant protection effort as well as costs can be omitted*)
  • Increases plant health and productivity [2] (the higher the humus content and the more varied the activation of the soil, the more stable is the humus content in the equilibrium and the healthier the plants can become – plant health is increasing due to the better and more balanced diet). Moreover, humus feeds and protects microbes in the soil, traps oxygen, which is essential for root development and helps root structures to grow by contributing to improved vigor.
  • The filtering and buffering effect increase (the higher the humus content, the better the pollutants can be captured and subsequently degraded). This includes filtering as well as purifying groundwater and rainwater.
  • Has a high sequestration potential of 2-25 tons of CO2 per hectare and year [3,4,5,6]
  • Increased reputation – the farmer becomes a climate protector and fosters sustainable developments: These include climate protection, water protection by reducing nitrate pollution, soil conservation by maintaining or rebuilding soil fertility, organic production by less or ideally no pesticide use, healthier food, more beautiful landscapes through hedges and agroforestry systems.
  • prevents erosion by holding soil particles together, protects the soil from extremes in tempera-ture and maintains soil pH, helping to correct soil pH problems.
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Approximately 2,500 billion tons of carbon are stored in soil humus worldwide, including about 1550billion tons of soil organic carbon (SOC) and 950 Gt of soil inorganic carbon (SIC). The carbon pool is 800 billion tons in the atmosphere and 560 billion tons in plant and animal life [7]. This is more than three times the total carbon in the atmosphere or nearly five times the amount bound in the whole plant mass. These facts alone show that humus has the greatest importance in the carbon cycle. Humus can highly contribute to mitigate climate change while providing multiple ecosystems services (co-benefits) for people. On this basis, FAO has estimated that soils can sequester around 20 billion tC (billion tons of carbon) in 25 years, more than 10 percent of the anthropogenic emissions. However, greenhouse gas emissions from agriculture, forestry and fisheries have nearly doubled over the past 50 years, and could increase an additional 30 percent by 2050 without greater efforts to reduce them [8].

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Humus formation practices can incline soil quality and fertility as well as simultaneously sequester anthropogenic GHG emissions. These practices include green manure and cover crop with legumes and perennial plants, crop rotation (e.g. maize-cereals/grains-maize or maize-winter barley-soya), intercropping (e.g. maize+beans, wheat+false flax, sunflower+buckwheat), catch crop (e.g. white clover under maize or cereals), agroforestry, no- or minimum-tillage, application of organic matter and compost as well as application of biochar etc.

Humus farming and climate positive agriculture has an immense potential to implement the sustainable development goals (SDGs) while mitigating climate change. “Eradicating poverty and ensuring food security can benefit from applying measures promoting land degradation neutrality (including avoiding, reducing and reversing land degradation) in rangelands, croplands and forests, which contribute to combating desertification, while mitigating and adapting to climate change within the frame-work of sustainable development” [1].

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There is an urgent need to establish large-scale humus farming practices not only to implement the SDGs e.g. increase yield for a growing population but also to reduce GHG emissions. On this basis, from the author’s point of view, on the global scale, humus farming area must receive more investment not only from public but also from private sector. Currently private sectors own 5 times more capital and wealth as the states.

On the European scale, the European Union must integrate humus farming practices and soil carbon enhancement as mandatory measures in the future of Common Agricultural Policy (CAP). For the 2021-2027 period, the European Commission is proposing an ambitious total budget of € 365 billion meaning that the CAP will account for just under one-third of the total EU budget. A minimum 30% of funding on rural development will be spent on climate and environment-related measures. 40% of the CAP’soverall budget is expected to contribute to climate action.

Fußnoten:

* Intergovernmental Panel on Climate Change, IPCC (2019): Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems.


Sources:

  1. Intergovernmental Panel on Climate Change, IPCC (2019): Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems.
  2. Oldfield, E. E., Bradford, M. A., & Wood, S. A. (2019). Global meta-analysis of the relationship between soil organic matter and crop yields. Soil, 5(1), 15-32.
  3. Dunst, G. (2011): Humusaufbau: Chance für Landwirtschaft und Klima. Verein Ökoregion Kaindorf.
  4. Jones, C. E. (2008): Liquid carbon pathway unrecognised. Australian Farm Journal, 8(5), 15-17.5
  5. Luske, B., & van der Kamp, J. (2009): Carbon sequestration potential of reclaimed desert soils in Egypt.
  6. Johnson, D., Ellington, J., & Eaton, W. (2015). Development of soil microbial communities for promoting sustainability in agriculture and a global carbon fix (No. e789v1). PeerJ PrePrints.
  7. Lal, R. (2004). Soil carbon sequestration impacts on global climate change and food security. science, 304(5677), 1623-1627.
  8. FAO – Soils help to combat and adapt to climate change (pdf)
  9. Alvaredo, F., Chancel, L., Piketty, T., Saez, E., & Zucman, G. (Eds.). (2018). World inequality report 2018. Belknap Press.

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