Heavy Rains Could Wash Away A Quarter Of Farm Soil By 2050

Severe storms will become more intense, more topsoils will be washed away due to higher levels of runoff.

Intense rainfall could wash away 13 to 23% of EU and UK farm soils by 2050, the European Commission’s science and knowledge service has warned.

Erosion could increase significantly in Ireland, most markedly in Connacht and Donegal.

But in general, soil loss is expected to be greatest in central and northern Europe, increasing by up to 100% in some areas.

Increased rainfall intensity is the main predicted cause of soil loss, which is driven primarily by climate change, but also by land-use changes.

Experts at the EU’s Joint Research Centre ( JRC) used 19 global climate models to predict soil loss by water erosion in Europe.

In 2016, they calculated, about 3.07 tonnes of soil were lost per hectare of EU agricultural lands per annum. With “business-as-usual” or modest mitigation measures, this is expected to increase to 3.76 tonnes by 2050.

Healthy soils produce our food and raw materials, clean our drinking water, reduce flood risks and store huge amounts of carbon. Pic. iStock.

The JRC researchers agree with the latest Intergovernmental Panel on Climate Change (IPCC) findings that climate change is widespread, rapid and intensifying, and that rising global temperatures may substantially affect desertification (water scarcity), land degradation (soil erosion, vegetation loss, wildfire, permafrost thaw), and food security (crop yield and food supply instabilities).

The main driver of soil erosion is rainfall intensity increasing by 16% to 26%. Severe storms will become more intense, more topsoils will be washed away due to higher levels of runoff.

Water will be less able to infiltrate the soils of arable crops, which may also increase soil losses.

Arable or permanent crops and pastures cover about 180 million ha in the EU and UK, of which 109m is arable crops (61% of total), 11.5m is permanent crops (6%), and 59m (33%) is pastures and mixed areas.

Some crops are less erosive (such as wheat, rice), whereas maize, tobacco, sugar beets are highly erosive.

Pasture land is less prone to erosion. Due to the EU’s predicted increase in pasture coverage, replacing croplands, soil erosion is expected to be 3% lower than without this land-use change.

The JRC recommends management practices and agro-environmental measures to avoid or reduce the projected increase in soil loss., along the lines of proposed soil conservation methods in the ongoing CAP reform for 2023.

The JRC says soil conservation measures such as cover crops, limited soil disturbance (reduced tillage), and diversification of cropping should be applied to at least 50% of soil erosion hotspots (areas projected to have more than five tonnes of soil loss per hectare per year).

Cover crops reduce soil loss by at least 20%, by improving soil structure, increasing infiltration, and protecting the bare soil from heavy storms.

Reduced tillage preserves soil quality and can reduce soil erosion by two-thirds.

Land use change from natural vegetation to agricultural land has strong links to increased rates of soil erosion.

Contouring, stone walls, and grass margins can reduce erosion, but it is scenarios with reduced tillage that have the greatest reduction potential. Use of reduced tillage is already increasing in areas with higher erosion rates.

By 2050, countries with currently low erosion rates, such as France, Denmark and the Netherlands, are expected to experience the largest soil loss increase.

In the Netherlands, increased rainfall and less ground in pasture (more arable) are projected to play big roles in almost doubling erosion rates, by 2050. Their predicted erosion increases, of 87% to 116% in two of the scenarios envisaged, compare with only 8% to 17% predicted in Ireland.

Soil erosion in southern Europe is projected to be largely unchanged, due to its expected decline in rainfall.

Soil is a thin layer that hosts a quarter of the planet’s biodiversity. Thousands of years are needed to create just a few centimetres of soil, so it is a non-renewable resource.

Healthy soils produce our food and raw materials, clean our drinking water, reduce flood risks and store huge amounts of carbon.

They are essential for achieving the objectives of the European Green Deal such as climate neutrality, biodiversity restoration, zero pollution, healthy and sustainable food systems, and a resilient environment.

Yet, European soils are degrading due to unsustainable management, overexploitation, climate change and pollution. Deforestation, overgrazing, unsustainable farming and forestry practices, construction activities and soil sealing, pollution from industrial emissions, or contaminants present in fertilisers or sewage sludge applied to soil, all damage soils.

The EU is developing a new soil strategy to combat these trends.

(Source – Irish Examiner – Farming – Stephen Cadogan – 13/09/2021)

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