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Irrigation and Organic Matter

27 June 2024

With climate variations, from wetter winters to drier summers predicted the agricultural sector needs to ensure that water supply is readily available when needed to maintain crop growth and livestock production.

Scotland’s abundance of water has been a key characteristic of this country’s heritage, however, water availability cannot be guaranteed. In this changing time, farmers and land managers need to incorporate management techniques and systems which can be implemented to help improve water availability when needed.

An important area to take into account when incorporating these techniques into your farm is the quality of irrigation and organic matter in your soil. This article will take you through the fundamentals and signpost further articles to help you develop your understanding further.

Know Your Soil

Soils are fundamental to your farm, ensuring and improving soil health can have great impact to how water is managed on farm. As shown in Figure 1 soils are integral to farming, having the ability to store more water that all the freshwater Scottish lochs put together. However, this ability is becoming more difficult as the stress and health on soil from the pressures seen in Figure 1. Improving soil structure and health can allow the soil to store water in situ for longer, allowing the farm to benefit from the additional water supply and allow for groundwater replenishment as will be discussed.

Figure 1: Scotland's soils source from


The Farm Advisory Service has vast array of documents and videos to help understand and enhance soils.

Understanding your soil and how it can work for you and the environment is key to success. The page is designed to help you evaluate your soil to ensure that you can make management decisions based on your soil requirements.

Ensure that you have consulted Valuing Your Soils practical guide as it provides key information on soil, its health and how to evaluate the soil to help your business.

The Prevention of Environmental Pollution From Agricultural Activity Code of Good practice has dedicated pages to help land managers understand their soil and methods to improve the soil on farm.

By improving the structure and health of soil you can improve infiltration of water within the soil and allow the storage of water during wet periods, prolonging the moisture content within the soil from which crops can utilise. The improvement of soil structure can significantly improve water retention on farm.

Farming and Water Scotland discussed with SEPA and SAC Consulting methods which land managers can implement to improve and enhance soil on farm. Protecting and enhancing soils on farm podcast can be found here.

Understanding Organic Matter

Organic matter can be defined as ‘all living, or once-living, materials within or added to the soil. The addition and enhancement of organic matter within the soil can:

  • Increase nutrients within the soil
  • Increase infiltration
  • Improve soil structure
  • Retain water
  • Reduce erosion risk
  • Provide carbon storage

Being able to improve soil organic matter can have great impact and improvement to the water retention, and by helping reduce the vulnerability of soil to erosion, therefore loss of soil to the water environment.

James Hutton Institute has produced Topsoil Organic Matter in Scotland mapping tool where land managers can compare their organic matter content with average soil organic matter for their area to ascertain the status of the organic matter present on farm.


Understanding Soil Moisture

Scotland’s soils has produced a mapping system to allow land managers to view the average available water capacity for their land. This resource is a method to see what your soils could be able to retain, albeit an average metric. However, it can be a great point of refence to start to understand and improve your soil structure. 

In-situ soil moisture sensors

Soil moisture sensors can optimise irrigation practices, enhance crop productivity, and contribute to sustainable water management. Technology such as wireless sensors provide real-time data on soil moisture levels, helping farmers to make informed irrigation decisions and reduce water waste. Using soil moisture sensor can help apply the right amount of water at the right time, allowing farmers to take proactive measures when it comes to the risk of drought.

Benefits of soil moisture sensors -

Soil Moisture Sensors benefits

Remote sensed soil moisture

Remote sensing offers new potential for quicker, more cost-efficient soil moisture monitoring and management than traditional methods. New drone technologies will allow for data to be collected and used to focus on areas where the water supply is not in line with best practices for soil health.

New scanners such as multi-spectral, thermal, or synthetic aperture radar (SAP) can be used to evaluate fields quicker than traditional soil testing. Multi-spectral monitoring involves the use of drone cameras to measure changes in the visible or near visible (infrared or ultraviolet) as a way of measuring water stress in plants and from light emitted from the soil itself. When combined with the appropriate measurement technologies, these scans can be used to identify areas where soil moisture stress may be present. Thermal imaging follows a similar principle but instead of looking at different light wavelengths, it focuses on the heat emitted by the surface and uses this to evaluate soil stress. Hotter soils will usually indicate drier soils and allow for land managers to better respond to times of drought by focusing on areas that are facing the highest levels of soil stress. Synthetic aperture radar is a system that allows for ground penetrating scans to evaluate soil moisture levels at both the surface and subsurface levels. This system would allow for even higher levels of soil monitoring by simplifying measurements needed for subsurface soils.

Each of these options does require a drone with the correct scanner, which depending on the location may be prohibitively expensive for farmers to access. Thermal and multispectral cameras are more common than SAP and are at a better price point for land managers. When soil moisture monitoring is being considered, new drone options may be a more cost-effective option for land managers moving forward.

Further Information

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