The impact of climate change on crop nutrient requirements
As climate change continues to reshape the agricultural landscape, UK farmers are facing a variety of challenges, from extreme weather events to shifting growing seasons.
One of the lesser-discussed but significant consequences is the impact on soil fertility and nutrient requirements for crops.
Among these, nitrogen is a key nutrient that plays a critical role in plant growth and productivity.
Understanding how climate change will affect nitrogen needs in the future is essential for farmers aiming to maintain healthy soils and ensure sustainable crop production
Changes in climate and the impact on nutrient cycles
Climate change is already influencing weather patterns across the UK, significantly impacting soil nutrient cycles.
In turn, this directly affects crop health and yields.
In the UK, farmers are being increasingly affected by conditions such as extreme rainfall, warmer temperatures and summer droughts, as a result of climate change.
These all have a knock-on effect on nutrient cycling and, in particular, nitrogen availability for crops.
- Extreme rainfall:
October 2022 to March 2024 was the wettest 18 month period on record, with 1,696mm of rain falling in the UK during this time1.
Intense rainfall can lead to the leaching of nutrients, especially nitrogen in the form of nitrates, from the soil. When heavy rain washes nutrients away from the root zone, plants have less access to essential nutrients, which can stunt growth and reduce yields.
Excessive rainfall can also lead to soil erosion, further depleting the soil of organic matter and essential nutrients.
Prolonged periods of heavy rainfall can cause soil to become waterlogged, reducing oxygen levels and hindering nutrient uptake by plant roots. It also disrupts soil microbial activity, which is vital for nutrient cycling.
- Warmer temperatures:
According to the Met Office, ‘the most recent decade (2014-2023) has been on average 0.42°C warmer than the 1991-2020 average and 1.25°C warmer than 1961-19902′.
Warmer temperatures generally accelerate microbial activity in the soil, which can increase the breakdown of organic matter and the release of nutrients, such as nitrogen, phosphorus, and potassium.
However, this can also lead to a faster release of nutrients than plants can absorb, resulting in nutrient loss through volatilisation or leaching.
Warmer temperatures can also lead to increased evaporation, which, in drier conditions, reduces the availability of water-soluble nutrients like nitrogen, causing a potential nutrient deficiency in crops.
- Summer droughts:
Projections suggest that average summer rainfall in the UK could decline by approximately 25% by 2050, with extreme drought events becoming more frequent3.
Drought conditions slow down microbial processes, reducing the mineralisation of organic nitrogen into plant-available forms. This limits the amount of nitrogen available to plants, potentially leading to nutrient deficiencies.
With reduced water availability, plants may struggle to absorb nutrients efficiently from the soil. This can result in an imbalance, where plants lack essential nutrients, despite their presence in the soil.
Drought can also cause soil to harden and compact, further restricting root growth and nutrient uptake. This limits the efficacy of fertilisation and reduces overall nutrient availability.
Managing nitrogen for climate resilience
As climate change continues to impact UK farming, managing nitrogen effectively will become increasingly important for maintaining soil health and crop productivity.
Here are a few strategies farmers can consider to manage nitrogen in a changing climate:
1. Optimised nitrogen application
One of the most effective ways to manage nitrogen use is to optimise the timing and amount of fertiliser applied.
Using precision agriculture techniques, such as soil testing and nutrient mapping, can help farmers apply nitrogen more efficiently, reducing waste and minimising environmental impacts.
With changing weather patterns, more frequent monitoring of soil moisture and temperature will be crucial to determine the right timing for nitrogen application.
Read further advice on how to tailor nutrition to your chosen crop variety.
2. Cover crops and nitrogen fixation
Incorporating legumes or other cover crops that fix nitrogen naturally can complement the use of nitrogen-based fertilisers, such as OCI Nutramon.
These crops can also help improve soil structure and organic matter content, enhancing overall soil health.
In addition to improving nitrogen availability, cover crops can help prevent erosion and reduce nutrient runoff during heavy rainfall.
Learn more: The impact of wet weather on crop growth – how can fertiliser help?
3. Adjusting crop nutrition based on weather forecasts
With the increasing unpredictability of weather patterns, paying close attention to weather forecasts will be more important than ever, to help farmers time fertiliser applications as effectively as possible and maximise nitrogen use efficiency.
For instance, applying nitrogen before heavy rainfall might lead to significant leaching losses, while applying it during a prolonged dry spell might reduce uptake efficiency.
4. Incorporating organic amendments
Organic materials, such as compost or manure, release nitrogen slowly, providing a steady supply of nutrition over a longer period.
These amendments also improve soil structure and water retention, which can be particularly beneficial in both dry and wet conditions.
Nutramon Low Carbon fertiliser
Amid the growing challenges of climate change, OCI is proud to have developed Nutramon Low Carbon fertiliser, a sustainable solution designed to minimise environmental impacts.
This product is successfully being used on malting barley and distilling wheat at Simpsons Malt’s farm in Northumberland and on other trial sites.
The aim is to decarbonise the supply chain of Scotch whisky, ultimately lowering the product’s carbon footprint.
References
- Yale Climate Connections, 2024. Climate change is a growing threat to UK farming: https://yaleclimateconnections.org/2024/10/climate-change-is-a-growing-threat-to-uk-farming/
- Met Office, 2024. Temperature extremes and records most affected by UK’s changing climate: https://www.metoffice.gov.uk/about-us/news-and-media/media-centre/weather-and-climate-news/2024/temperature-extremes-and-records-most-affected-by-uks-changing-climate