The black gold of Ukraine and the most fertile soils in the world

09/03/2022

Ukraine is the breadbasket of Europe thanks to its fertile soils known as Chernozems. This 'good black earth' is among the most productive soils in the world, a fact Russians are well aware of. Russia has a long tradition of soil science, and its experts have made significant contributions to the field. If the Russia aim to conquer Ukraine, the fertile black soils are without any doubt one big bullet point on their agenda. We explain what Chernozems are, where the world's most fertile soils are found, and explore some parallel situations - and disasters - in the Americas.

Author: Kathelijne Bonne 

Chernozems, the black soils of Ukraine

Chernozem is the name of the soil type occurring in Ukraine, according to the World Reference Base of Soil Resources (WRB), the soil classification system of the Food and Agriculture Organization of the United Nations (FAO). They are characterized by a thick black upper layer or A horizon, the "chernic horizon" which must be at least 25 cm thick and is rich in decomposed plant material and therefore contains a lot of humus and carbon. In Ukraine, the thickness of the chernic horizon can be up to several meters!

Black earth of e Chernozem soil in Russia.
Black earth of e Chernozem soil in Russia.
Chernozem soil profile in Ukraine.
Chernozem soil profile in Ukraine.

The importance of humus and nutrients

Humus are organic acids, complex molecules, formed after decomposition of plant parts and digested by soil organisms. Thanks to the chemical structure of humic acids, they not only retain water, but also nutrients, such as calcium, magnesium, potassium, ammonia, phosphorus, sulfur, iron, manganese, zinc, copper, etc. In contrast, in humus-poor soils, rainwater or irrigation water and the dissolved nutrients, simply sink to deeper aquifers, beyond the reach of plant roots. Humus-rich soils can bridge a dry season because of these properties.

Chernozems also has a very good structure, that is, plant roots have no trouble branching out into the soil and there is enough oxygen so that soil organisms can breathe. Biodiversity and abundancy of organisms is high in Chernozems, and they are active at greater depths than in other soils, further improving the soil structure. The soil also contains a lot of calcium, so it does not easily become acidic. All of these properties mean that a Chernozem does not need much additional fertilizers or soil conditioners and produces good yields, provided it is managed sustainably.

Dukochaev, the father of soil science.
Dukochaev, the father of soil science.

Russian father of soil science

The name Chernozem (from chorniy, black and zemlya, land, earth, in Russian) was coined in 1883 by the Russian geographer Vasily. V. Dokuchaev, the founder of soil science. He recognized that agricultural productivity was largely determined by the type of soil, and that this in turn was influenced by geology, relief, climate, organisms, and the time taken to form a soil. The name Chernozem was adopted from the Russian classification when the FAO created the WRB, its own globally applicable classification system, in the 1980s and 1990s (*). Several Russian names are now fully established in soil science circles.

The Americans did not adopt the Russian nomenclature, and developed their own method: the Soil Taxonomy of the US Department of Agriculture (USDA). This system, too, is applicable worldwide and was drawn up after the agricultural disaster of the Dust Bowl in the 1930s. In the Soil Taxonomy, Chernozems correspond to the category of Mollisols (which also includes other related soil types) after mollis, soft, and sol, soil, in Latin.

(*) Many countries have their own local system of classifying soils. This is useful for local food production. For example, for Icelandic farmers it is not very relevant to know how one deals with farming problems in the Tropics. Globally applicable classifications are especially useful for knowledge exchange, policy making, and to provide food security in a globalized world. Soil classification are also continuously updated, based on new knowledge and needs. Note as well that both Mollisols and Chernozems can still be divided into many subclasses, they are anything but homogeneous.

Distribution of Chernozems (red) (UN).
Distribution of Chernozems (red) (UN).
Distribution of Mollisols (USDA).
Distribution of Mollisols (USDA).

Soils of the steppes, prairies and pampas

One-fourth of the world's Chernozems are located in Ukraine, and the country itself consists of 68% of this type of soil. Chernozems extend across two major black-earth belts in the world, in the steppes of Eurasia from Ukraine to Russia, and in the prairies of the Great Plains in North America. They are typical of grasslands in continental climate belts with cold winters, rainy springs and hot summers. Similar soils, with slightly different characteristics (Mollisols), stretch over vast regions in the Argentinean pampas.

Agricultural and climatic potential of Ukraine

To date, Ukraine is one of the three largest grain exporters, and a world leader for soy, maize and sunflower oil. The blue-yellow flag is reminiscent of the vast golden-yellow grain fields under a blue sky. In addition to the EU and surrounding countries, the Arabian Peninsula is an important market. Ukraine also began to establish itself as an important country for the export to the EU of organic crops. The UN also identified Ukraine's potential in regenerative agriculture, a sustainable form of agriculture that does not harm the environment and increases biodiversity. They also looked at the potential to capture carbon from the atmosphere, and sequester it in Ukrainian soils.

Soil degradation in Ukraine 

But this vast soil wealth is too good to be true. Ukrainians are people like me and you who, like our fellow humans elsewhere in the world, inflict great damage to the environment. In theory, Chernozems can feed the world, but in practice they are subject to predatory agriculture and soil erosion, the washing away of the soil by unsustainable practices, caused by plowing, monocultures, irrigation, fertilization, fallow systems, etc., among others. It is estimated (in this FAO report) that Ukraine loses 500 million tons of soil per year through erosion, which equates to a loss of $5 billion per year in nutrients. Or in another calculation, per ton of grain produced, 10 tonnes of soil are lost. The same FAO report offers solutions and methods for conservation agriculture (CA) and climate-smart agriculture (CSA), which have already been successfully applied in Kazakhstan and elsewhere.

Gone with the wind: soils blown away

Despite their good reputation, we can completely lose the best soils in the world, the Chernozems or Mollisols. The Dust Bowl may not ring a bell with most people today, yet it was a huge disaster in the 1930s in the Great Plains of the United States and Canada, where Mollisols naturally occur. Deforestation, plowing, and prolonged drought in this American "breadbasket" resulted in tragic soil erosion. Winds blew away the top layer of soil that had been reduced to dust; dust clouds darkened the sky to thousands of miles away. Hundreds of thousands of farmers left their fields and moved to California and Oregon to start new lives. John Steinbeck's Pulitzer Prize-winning book The Grapes of Wrath is about this event, and many a film was made about it as well.

The New Black Gold

The world is at a tipping point, and the consequences of the war in Ukraine will ripple across societies worldwide. The soil issues will make it worse. Because phenomena such as the Dust Bowl, or other disasters, may occur again, and it would be a pity if this were to happen to the world's best soils. Therefore, we need to remind ourselves what the basis of a stable, prosperous society is, and that is healthy food, clean water, clean air, and sustainable renewable resources, to which everyone has access. If these are in place, the energy transition can be accomplished peacefully. Therefore, sustainable management of forests, oceans and soils should be at the top of political agendas worldwide.

It seems that petroleum is no longer the black gold, the heyday of Big Oil is over, however well it has raised living standards to their current levels (at least in some rich countries). Good black soils, like the Chernozems of Ukraine, are the black gold of the future (and in fact they always have been, it's just that soils never get the attention they deserve, and we are so far removed from nature that we are no longer aware of what we owe our prosperity to). Petroleum and gold cannot be eaten. Neither can money, as the Native Americans noted long ago. It is therefore of the utmost importance that soils, even if they are not Chernozems, are sustainably managed anywhere in the world.

Dust clouds from the Dust Bowl in Texas, 1935.
Dust clouds from the Dust Bowl in Texas, 1935.
Book about the Dust Bowl by John Steinbeck.
Book about the Dust Bowl by John Steinbeck.

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Important note: we talk in this article about fertile and productive soils in terms of human food production, hence adopting an antropocentric view. But also soils that do not produce crops for human consumption carry out important ecosystem services and are no less important for ecosystem and planetary health. 

Images:

Title picture: https://en.wikipedia.org/wiki/Economy_of_Ukraine#/media/File:Flag_colors.jpg

Black earth in Russia: https://upload.wikimedia.org/wikipedia/commons/f/f2/Black_Earth_-_Prokhorovka_-_Russia.JPG?uselang=fr
Chernozem soil profile in Ukraine: https://fr.wikipedia.org/wiki/Tchernoziom#/media/Fichier:%D0%A7%D0%BE%D1%80%D0%BD%D0%BE%D0%B7%D0%B5%D0%BC.JPG

Others: public domain.

Sources:

FAO, Ukraine: Soil fertility to strengthen climate resilience: Preliminary assessment of the potential benefits of conservation agriculture https://www.fao.org/3/i3905e/i3905e.pdf

Atlantic Council, Ukraine can feed the world: https://www.atlanticcouncil.org/blogs/ukrainealert/ukraine-can-feed-the-world/

IUSS Working Group WRB. 2015. World Reference Base for Soil Resources 2014, update 2015 International soil classification system for naming soils and creating legends for soil maps. World Soil Resources Reports No. 106. FAO, Rome.

United States Department of Agriculture, Natural Resources Conservation Service, Soil Taxonomy, a basic system of soil classification for making and interpreting soil surveys, 1999, by Soil Survey Staff, Agriculture Handbook 436.

World Bank, 2014, Soil Fertility to Increase Climate Resilience in Ukraine, https://www.worldbank.org/en/news/feature/2014/12/05/ukraine-soil

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