Carbon Footprint Calculators

What to consider when deciding which calculator tool to use?

  • It is recommended that the same calculator tool is used year on year in order to provide a more accurate monitoring system as calculations do vary considerably between tools.
  • Each calculator makes different assumptions and considers different factors.
  • The greater the energy consumption on a farm, the more difference there are between the tools because embedded calculations are magnified.

Below are brief introductions to a selection of carbon calculators.


CALM Carbon Calculator 

CALM is an abbreviation for Carbon Accounting for Land Managers. The CALM Carbon Calculator has been produced by the Country Land and Business Association (CLA) in partnership with Savills. It measures the emissions of GHGs in relation to energy and fuel use, livestock, cultivation and land-use change and application of nitrogen fertilisers and lime against any carbon stored in trees and soil. It is not a measure of carbon capture (sequestration) but rather the annual change in emission pre and post entry. 

The free web-based calculator allows the user to input a lot of data and therefore gives the impression that little is assumed. For example, in terms of livestock, the user can specify details such as livestock numbers, age, amount of days per year grazing and what percentage of manure is produced and stored as FYM or slurry. It also allows the user to input a lot of detail in terms of fuel consumption and nitrogen content of fertilisers. Less detail is required in terms of carbon sequestered by woodlands and consequently more is assumed.

To find out more or to use the CALM calculator click here



Farm Carbon Calculator  

The Farm Carbon Calculator is part of the Farm Carbon Cutting Toolkit, a non-profit organisation dedicated to helping farmers and growers get to grips with carbon emissions. Jonathan Smith, an organic grower from the Isles of Scilly who runs Scilly Organics, is the lead developer. If you are interested in his account on creating the calculator; the process, thinking behind it and how it can benefit a farmer or grower, look at Out and about carbon footprinting.

The main difference between this carbon calculator and others is that it takes in to consideration carbon emissions through processing and distribution beyond the farm gates but does not take in to account land use changes. It also considers carbon emissions stored in farm vehicles, building materials and consumables whereas other tools do not.

Version 3.0 is now available  and includes new features such as agro chemicals, waste and a new easier-to-use distribution section.

To find out more or to use the FCCT calculator click here.


CPLAN v0 and CPLANv2

The CPLAN calculator was designed by farmers in central Scotland for land based industries and farmers. CPLANv0 is a free online anonymous calculator while CPLANv2 is for members only. It is free to register for CPLANv2 but a small fee is charged to perform the calculation and generate the report. CPLANv0 makes more assumptions and requires less data input and does not take grasslands into account when determining nitrous oxide emissions from crops.

CPLAN v2 is the only web based model that provides the user with both the average and upper and lower estimates of their greenhouse gas budgets. It also allows the user to opt for standard or customised data; customised allows for a lot of detail while standardised makes more assumptions. For example, v2 allows the user to specify species and year of planting whereas v0 only allows the user to differentiate between broadleaf and conifers, and select age brackets.

To find out more or to use the CPLAN calculator(s) click here.



This calculator has been developed by the Low Carbon Farming Project. It claims to be different from other calculators principally through the feedback report generated which highlights areas for improvement, providing targeted, technical support. Users are encouraged to monitor their progress towards best practice in relation to low carbon farming, lowering the emissions impact of their farm, saving valuable resources and improving the overall efficiency of the farm.

The calculator does require the user to collect specific livestock data but provides a data collection sheet and instructions to help do this.

To find out more or to use the FCAT calculator click here.


Sources: Case-study comparison review by the Soil Association, and the website for each of the carbon calculators.


Soil Identification

Identification of soil group
Identification of soil texture

What is compaction?

  • Soil scientists describe good soil structure as having 50% of the soil volume occupied by particles of soil and organic matter, 25% by water, and 25% by air
  • Compaction describes when soil has been squashed into a solid impermeable layer, either at the surface or within the topsoil. This band of squashed soil restricts the movement of air, water, and nutrients down through the soil profile
  • For more information please click here

What causes compaction?

  • Soil composition and moisture content affect compaction, with wet and clay type soils being more prone to compaction
  • Ground pressure on soils imposed by tracks or wheels
  • Approximately 80% of soil compaction occurs during a machine’s first pass over loose soils
  • Poaching from livestock causes compaction, due to overstocking, or grazing animals in susceptible fields in wet conditions
  • Read more

How can I identify compaction?

  • Dig a hole to a depth of 30cm when the soil is not excessively wet or dry
  • Notice how far roots and moisture extend down the soil profile, and any obvious changes in soil structure
  • Pay particular attention of any areas where the spade meets resistance. The depth of resistance will help indicate the cause of compaction
  • For more information and to register for a free advice visit from the Soils for Profit scheme, in which compaction can be targeted, please visit the Soils for Profit page.
  • Watch the video at http://www.environment-agency.gov.uk/business/sectors/123420.aspx

Costs of compaction

  • It impacts on a wide range of processes that occur in soil leading to a reduction in yield from the affected field, increased nutrient loss and soil degradation
  • It reduces the ability of grass to utilise fertiliser as the roots cannot fully exploit the soil and reach the nutrients
  • It reduces the uptake of artificial fertiliser - if the soil becomes waterlogged this causes the fertiliser Nitrogen to convert into gases which are lost to the air
  • It reduces the availability of mineralised Nitrogen from soil organic matter and the Nitrogen fixing potential of legumes (including clover)
  • It reduces the crop germination rates, plant seedling establishment and crop emergence
  • Read more

How can I get rid of compaction?

Download document here.

What are the benefits of removing compaction?

  • Introduction of oxygen to the soil which improves biological and worm activity
  • The physical opening up of the soil structure improves surface drainage and absorption of slurry which helps reduce run off
  • Increased rooting activity which improves the plant’s ability to use nutrients and trace elements
  • More persistent leys with more grazing days per season, and less need for reseeding
  • A more effective microbial population fixes Nitrogen for free, and improves utilisation of applied fertiliser. Grass on uncompacted soil can recover 60% of applied fertiliser , whereas only 26% of applied fertiliser is recovered by the crop in compacted soil (Defra, 2000)
  • Well aerated soils warm up faster in the spring and recover faster after grazing and cutting
  • Increased yields – a potential grassland yield increase of up to 900kg DM/Ha in the following year after addressing compaction issues. A crop of grass silage (£30/t) would result in an extra £108/ha (2006)
  • IGER trials have shown that aeration and the removal of compaction can increase productivity in grazing swards by 26kgDM/Ha/day and also due to the physical opening up of the soil, reducing ammonia losses and boosting the nutrients available to the plant (2006)
  • Read more

Step 1: Extract the soil block

If it is loose soil, remove a block of soil about 15 cm thick or to the full depth of the spade and place the spade and soil on to the ground or a surface where it can be easily examined.

If it is firm soil, dig a hole slightly wider and deeper than the spade leaving one side of the hole disturbed. On the undisturbed side, cut down each side of the block with the spade and remove the block placing the spade and soil on to the ground/surface

Step 2: Examine the soil block

If the soil block is a uniform structure, remove any compacted soil or debris from around it. If there are two or more horizontal layers of differing structure, estimate the depth of each layer and make sure that you assign scores to each separately (see step 7).

Step 3: Break up the block

Gently manipulate the block using both hands to reveal any cohesive layers or clumps of aggregates. If possible separate the soil in to natural aggregates and man-made clods. Clods are large, hard, cohesive and rounded aggregates.

Step 4: Break up the aggregates

Break large pieces apart and look at the internal structure of the cross-section. A crumb-like appearance with rounded aggregates easily broken apart and embedded in a finer matrix indicates a well-developed natural structure and lower score.

If clods can be broken in to non-porous aggregates with angular corners it would indicate poor structure and therefore a higher score.

Identification of Soil Group

Source: Think Soils, Environment Agency

Identification of Soil Texture

Source: Think Soils, Environment Agency