Bombs, mines and chemicals: how agricultural soils in Ukraine have been ravaged by war

The Ukrainian region of Kharkiv has some of the most fertile soil in the world, producing grain for local and global markets. After the Russian invasion in 2022, however, wheat production dropped by more than half. Over 160.000 hectares of land in Kharkiv have been damaged by the war. The region is marred by 420.000 craters.

20 billion dollars

‘There is an assumption that Ukrainian food production can return to normal after the war’, says Wilfred Dolfsma, professor of Business Management and Organisation at Wageningen University & Research (WUR). ‘Unfortunately, that is not the case.’

Together with colleagues from Ukrainian and Dutch universities, Dolfsma estimated the cost of restoring Kharkiv’s agricultural soil after the war. The researchers first analysed the damage to the landscape using high-resolution satellite imagery. This method was previously applied in conflict zones like Syria and Darfur. They then calculated the cost of surveying and demining the soil, filling craters and other steps that will have to be taken to restore agriculture: at least 2 billion dollars.

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Kharkiv is only one of ten Ukrainian regions (oblasts) that have been severely affected by the war. Dolfsma and his colleagues assume that the cost for the other nine oblasts will be similar, since the damage in Kharkiv is estimated to fall between the most affected regions (such as Donetsk and Kherson) and those that are less affected.

Following these assumptions, the researchers arrive at a total cost of 20 billion dollars for the restoration of Ukraine’s agricultural soil. This amount is equivalent to about 15% of the country's GDP before the war. The true cost will likely be even higher, says Dolfsma: ‘This estimate doesn’t include costs for machinery, fuel or labour. Estimating those factors is too speculative. The cost of removing contaminated soil, for example, depends on things like the accessibility of the fields and rainfall interrupting the work.’

Black earth

To understand why Ukrainian farmlands have been so heavily damaged by three years of war, it’s useful to zoom in on the soil itself. Why is it so fertile in the first place? The answer lies buried in the black soil that can be found across the country. It is called chernozem, which can be translated as “black earth”. Under the right climate conditions, chernozem is formed in steppe areas with high grass, which are prevalent in eastern and southern Ukraine as well as other parts of Europe and Asia.

‘That dark colour indicates a high presence of organic matter’, explains Giulia Bongiorno, lecturer in soil biology at WUR. ‘Decomposed plant material, micro-organisms and other forms of organic matter are very important for soil fertility. They provide many functions: retaining and releasing nutrients like nitrogen, phosphorous and potassium, holding water, improving the structure of the soil, and more.’ All those functions supported the rich grain harvests Ukraine was famous for.

Craters and bombturbation

The rich chernozem soils have been heavily damaged by the full-scale Russian invasion that started in 2022. ‘War has different kinds of impact on soils’, explains WUR researcher Serhii Sydorenko. Sydorenko, who is from Ukraine himself, conducts research on the consequences of wildfires during the war. ‘The impact can be mechanical, like soil compression by heavy military equipment or the formation of trenches and craters. It can also be chemical, such as the contamination of soil with heavy metals and rocket fuel.’

Soil compression is already a serious problem in agriculture, where tractors and other heavy machinery push down heavily on the ground. ‘Military vehicles like tanks are much heavier and therefore more damaging’, says Bongiorno. ‘As they press the soil layers together, there will be less space for water and oxygen. These conditions will result in a habitat that is detrimental for organisms that live in the ground, like soil fauna and plant roots.’

‘The mixing of different soil layers due to explosions is probably even worse’, Sydorenko adds. ‘The upper half-meter is the richest part. Explosions cause all the layers to violently blend together, destroying soil life. This makes the soil much less fertile.’ The effects depend on the type of weapon used, he adds. ‘Some aerial bombs and missiles leave craters with a depth of six meters. These craters also completely change the topography of the landscape. Craters will make it very difficult for farmers to manage their lands.’

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In soil science, the cratering and mixing of the soil by explosive munitions is called bombturbation. This term was first used by two American geographers to describe the impact of craters on the landscape of Verdun after World War I. Explosive munitions such as missiles and artillery shells contaminate the soil with chemicals and heavy metals. Recent surveys in Ukraine have shown sharply increased levels of soil pollution with metals like cadmium, copper and zinc, as well as fuel products.

An often overlooked effect of the war is the destruction of windbreaks. These long rows of trees and shrubs border almost every field in Ukraine. ‘Windbreaks play a vital role in agricultural landscapes’, Sydorenko explains. ‘They provide shelter from the wind, preventing soil erosion and preserving soil moisture. But many of them have been damaged, destroyed and used as fortifications or camouflage. Their destruction has many cascading effects, like soil degradation and a higher risk of desertification.’

Return to agriculture?

It may take many years for Ukraine to restore its agricultural lands after the war. Some problems may be too severe to be solved in the near future. Giulia Bongiorno is concerned about the contamination of the soil: ‘We don’t know the exact impact of heavy metals on food quality. At a high concentration, they can cause problems for plant growth and the quality of the food. In any case, detecting heavy metals is not routinely done. It requires expensive equipment.’

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‘In Ukraine, we understand that some areas can’t just be returned to agriculture’, adds Sydorenko. ‘There are fields that can’t be demined easily, and many fields will contain unexploded ammunition deep in the ground. So we are even discussing the possibility of turning some lands into protected areas.’ To this day, farmers in Flanders still encounter unexploded munition from World War I while ploughing their fields.

Another complication that Ukraine might face after the war has to do with the geographical distribution of chernozem. ‘Many fertile soils overlap with the frontline of the conflict, in eastern and southern Ukraine’, says Sydorenko. ‘These areas have been hit very hard. Most of them are heavily damaged, contaminated or occupied by Russia.’

These difficulties highlight the need for coordinated policy to support Ukraine’s recovery after the war. The recovery will require significant investment, Wilfred Dolfsma emphasises: ‘20 billion dollars is our first estimate. And of course, it’s not just about money: there will be a high demand for machinery and people, who will have to be trained. And all the while, Ukrainians also have to rebuild houses, infrastructure, and so on. So policymakers need to understand that it will take a lot of time and investment for the grain to start flowing again.’