Here's some questions we frequently get asked
We hope the following common questions can help guide you through the Agrecalc journey. Any remaining questions about our data input fields are likely answered in the Agrecalc User Guidance after you log in. If you cannot find an answer to your query here, please contact us for additional support.
Q. G1. What emissions are included in Agrecalc?
A. G1. The boundary for Agrecalc is to the farm gate. We focus solely on all emissions related to agricultural production on the farm. These emissions generally account for more than 95% of the greenhouse gas emissions related to food products. Transport, processing, and packaging after products are sold off the farm is not to be included in our emission model at present.
Q. G2. What modelling methods does Agrecalc use?
A. G2. Agrecalc is committed to maintaining a consistent, defensible model of farm emissions based on the latest reporting standards and research. Agrecalc is based primarily on the International Panel on Climate Change’s Guidelines for National Greenhouse Gas Inventories. We use mostly tier 2 modelling methods to estimate greenhouse gas emissions from all major on-farm sources and carbon sequestration. We also incorporate more specific national figures from the UK National Greenhouse Gas Inventory. We complement these standard modelling methods with data from scientific databases and other published research. More information on our model, please see our modelling methodology.
Q. G3. What period of the year should the audit take place?
A. G3. To set up a report in Agrecalc, you will need to specify what month the audit starts and concludes on the farm report data entry page. This must be a 12-month period. Essentially, this can be done over any 12-month period in the year as long as it is consistent from year to year, so that subsequent years can be compared to the baseline. For example, some farms will align with the calendar year, or some might align with the financial year.
In future releases, we plan to allow audits for periods shorter than 12 months. This will be particularly useful for pig and poultry farms that operate on a shorter cycle. Farms with grassland or crops will align more easily with an annual cycle.
Q. G4. How do I interpret the results?
A. G4. There are several ways to view your results in Agrecalc. We currently include options to view results through a resource use and emissions table, comparisons, year-on-year results, charts and Agrecalc pdf reports.
The resource use and emissions table shows a line item and breakdown for every source of emissions across the whole farm and also for each individual enterprise and product. Although this table does not give much context to the numbers, it includes all the relevant output figures from the entire report for reference. It can also be copied into excel for further modelling or data manipulation. The charts functionality displays data from this table in a more visual and digestible way. These two functions together can help you identify the major contributors to your greenhouse gas emissions.
The Agrecalc reports include KPIs and benchmarks, which are especially useful for interpreting results. The benchmarks allow you to compare your farm with similar farms in the Agrecalc database, demonstrating areas in which you excel and areas for improvement. The comparisons tool allows for placing two Agrecalc reports side by side and comparing each line item to examine any differences. This functionality is useful in a variety of modelling contexts. The year-on-year option allows a similar way side-by-side comparison of line-by-line changes over time.
Q. G5. How do you model a ‘What if’ scenario using Agrecalc?
A. G5. Let’s take an example – say you want to model a 25% reduction in fertiliser use. On the farm home page, first create a copy the baseline report. Then, enter the report input screens and reduce fertiliser quantity by 25%. Remember to hit ‘Save’. Next, use the ‘Comparisons’ page in the results section to compare the results of both reports side-by-side. It is advisable to initially model one variable at a time so that you can see the effects of each change in isolation before layering scenarios.
Q. C1. How does a farm allocate land that is rented out seasonally?
A. C1. Agrecalc is an LCA tool that seeks to assign the emissions associated with agricultural production effectively. Where land is rented out by the landowner, the guiding principle is that the carbon emissions are allocated to the farmer that generates the output. If the landowner or farmer rents land out to someone else, the emissions are passed to the third party and do not reside with the landowner (if they are not your sheep they are not your emissions). The same applies to crops such as land let for potatoes – the landowner is not responsible for fuel and fertiliser that the potato grower applies to the crops.
Q. C2. How do I answer the ‘Number of years crop is in the ground’ field?
A. C2. This is the average length of time the crop is in the ground before it is ploughed and should be recorded in years. For annual crops, this value should be one, for other crops such as grassland the value used should be the average age of the rough grazing, pasture or grass ley.
Q. C3. On a farm with crops or grass, there are no figures for nitrous oxide emissions from crop residues to be seen in the results?
A. C3. The Crop Residues calculation requires data to be added for Number of years crop is in the ground.
Q. C4. Is it possible for the tool to take peatland into account?
A. C4. Not at present – though we are working on a collaboration to take this into account. For now, some of our soil specialists have been doing survey work, following guidelines in the Peatland Code to calculate potential emissions savings from peat restoration. The next step for Agrecalc is to account for emissions from drained, cultivated peat soil. After that, we aim to add peatland restoration to the Agrecalc sequestration model.
Q. C5. How do I answer ‘Fraction of perennials / fallow in the rotation’ in the soil carbon inputs?
A. C5. This field asks what fraction of the rotation the field is under perennials / left fallow. Consider a longer time scale than the year in question for the purposes of the soil carbon calculations. For example, if every 2 years in 8, a field is sown with perennials grasses, the value entered would be 25%.
Q. C6. How do I input liquid fertiliser in Agrecalc?
A. C6. You can enter the N% in the usual fertiliser tab and convert from litres (L) to tonnes (t) by multiplying the quantity applied in L by 0.00128.
Q. C7. Are there standard figures for ‘% crop removed’ values for different crops?
A. C7. Yes, these can be found in the user guidance notes. Click here. If straw from cereals is chopped or incorporated, this should be factored in, as less of the crop is removed from the field. Adjust the proportion removed based on the yield of straw remaining but yield of grain being removed. See further instructions in the User Guidance. If standard figures aren’t included in the User Guidance, contact us and we can provide an estimate.
Q. C8. Why does lime have a large impact on my carbon footprint and how should I enter it?
A. C8. Lime application leads to direct soil emissions: lime releases carbon dioxide when it dissolves in the presence of water. Lime is also quite carbon intensive to extract and deliver as a product to the farm gate.
It is often the case that lime is only applied one in every four or five years. We recommend spreading the amount of lime applied across the number of years in which subsequent crops will benefit from the application.
Q. C9. On an organic farm that doesn’t use fertiliser, why do emissions against fertiliser appear in the emissions tables?
A. C9. This category includes Fertiliser and Lime – lack of space in table prevents full title being detailed there.
Q. C10. What is the meaning of the ‘Biodiversity’ land use category?
A. C10. Biodiversity area includes shelter belts, wetlands, wildflower meadows, and other natural areas which are not part of the farm production system but are kept in a natural state to support the natural landscape. Areas of bracken can also be recorded under biodiversity.
Q. S1. What is the difference between soil carbon stocks and soil carbon sequestration?
A. S1. You can think of the soil as a bank account for carbon. Carbon stocks are the account balance, and sequestration is the profit or loss. Carbon is only being actively sequestered by the soil if the balance is increasing over time.
Soil carbon sequestration is calculated as the change in soil carbon stock estimates from one year to the next. Soil carbon stocks are determined by climatic factors such as temperature and moisture content, as well as mineral composition and soil texture (I.e. the relative proportions of sand, silt, and clay particles that make up a particular soil). Generally, the soil carbon stocks in the UK vary between 80–120 tonnes C per ha. Changes in the management of the land may affect whether these resting soil carbon stocks are maintained, increased, or depleted.
Q. S2. What is the difference between soil organic matter (SOM) and soil organic carbon (SOC)?
A. S2. Soil organic carbon (SOC) is a component of soil organic matter (SOM). Although the two soil properties tend to correlate, they are not the same. While soil organic matter testing provides a good indication of overall soil health and carbon storage potential, it is not sufficient for calculating soil carbon sequestration or quantifying soil carbon stocks for greenhouse gas reporting or carbon market payments. If you are just interested in knowing about the health of your soil and your carbon storage, soil organic matter testing might be sufficient. If you need more quantitative information on soil carbon sequestration potential, a soil organic carbon test to 30cm might be needed.
SOM makes up a relatively small proportion of the soil’s mass but plays a vital role in soil biological, chemical, and physical functions, such as soil structure and stability, regulating drainage and trafficability, buffering nutrient supply and sequestering carbon. SOM contains all organic material present in soil, including plant, microbial, algal, and animal materials in different stages of decomposition. It is a key store of nutrients such as carbon, nitrogen, phosphorus, sulphur, potassium, calcium and magnesium. SOM is the largest terrestrial reservoir of soil carbon – soil organic carbon (SOC) is a measurable fraction of SOM that contains carbon from organic compounds. Generally, SOM is made up of around 58% SOC.
Q. L1. What is the definition of digestibility used in Agrecalc calculations?
A. L1. Agrecalc uses the IPCC definition of digestibility: “The portion of gross energy (GE) in the feed not excreted in the faeces […] Feed digestibility is commonly expressed as a percentage of GE or as TDN (total digestible nutrients).”
Digestible energy is not exactly the same as metabolisable energy, as the latter refers to the portion of feed which is not excreted in faeces or urine. Guidance is included here https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch10_Livestock.pdf starting on page 10.19, including guidance for default values.
Q. L2. If I am contract rearing dairy heifers how would I enter that in the tool?
A. L2. In this case you can just enter the animals in as beef animals that have been purchased in and then sold out again. As far as the model is concerned these are you cattle for the 18months or whatever period you have them for as your are farming them for this period.
Q. L3. What if my farm has multiple enterprise types e.g. different sheep flocks?
A. L3. In the current version of Agrecalc, just select the system type that represents the largest flock. In the new platform (to be released later this year), users will be able to separate multiple flocks under different management regimes in Agrecalc’s inputs.
Q. L4. Does the enterprise type selected affect the carbon footprint results?
A. L4. Enterprise system types are required for all livestock enterprises, and this data affects the typical values used in Agrecalc. This includes default weights, diet digestibility, and crude protein. If you do not select an enterprise type for a livestock enterprise, feed ration data will not be populated with defaults and emission calculations will not run as expected. System type data is also used for benchmarking purposes.
Q. E1. When calculating external haulage, would you calculate one way or round trip haulage for fertiliser, feed, hay, etc. delivered to the farm and how many trips would you include?
A. E1. Agrecalc calculates emissions to the farm gate – not beyond. The embedded emissions for inputs such as feed and fertiliser are assumed to include delivery to the farm gate. Therefore, external haulage figures should not include the transport of inputs onto the farm nor of products off the farm to their final point of sale / processing.
The intended role of external haulers in Agrecalc is to capture movement of livestock or crops within the farm business – for example, moving wintering sheep to distant rented grazings. Other transport using tractors is captured in the red diesel usage.
Q. E2. An arable farmer with their own lorry which hauls their own grain to the end buyer. Their white diesel usage is very high compared to the benchmark.
A. E2. The boundary for the Agrecalc emissions model is the farm gate. This farmer should exclude white diesel used by their own truck(s) for transporting grain from the farm to the end user.
Q. E3. If a farm has electricity usage that is partly conventional and partly renewable, is the usage that goes in the electricity box just the conventional usage?
A. E3. This is correct. The renewable usage should only be accounted for on the renewable electricity tab. The electricity use input includes electricity from the national grid or local conventional generation.
Q. E4. A farmer pays a renewable electricity tariff but the electricity is supplied by the grid. How should this situation be handled in Agrecalc?
A. E4. Regardless of the tariff paid, all electricity from the national grid should be entered in the electricity input rather than the renewables input box. This is in line with current best practice for greenhouse gas reporting, which states that the emission factor for grid electricity should be used regardless of the tariff paid. This avoids double counting emission savings reported by the energy company.
Q. E5. Often the same meter is used for the farmhouse and the farm business. Should I include the farmhouse electricity is the farm carbon footprint?
A. E5. Anything that does not contribute toward the final product that is sold off the farm or result in other farm output, is not included. Therefore, electricity for the farm house or any other heating fuel would not be included in the farms carbon footprint.
Q. E6. If I also do some contracting in addition to work on my own farm how do I account for diesel used when doing contracting work on other farms? Does this go on my footprint?
A.E6. If you do some contracting in addition to work on your own farm, you will need make a best estimate of how much of the fuel used was for work on your farm and how much was for work on another farm. Similarly, if you have a contractor do some work on your farm then you would need to estimate the fuel used by contractors and include that in your footprint.
Q. G1. Why are my emissions showing as zero?
A. G1. This can happen if an enterprise category has been omitted / unclicked on the first data entry page – “Farm Report Data Entry”. Ensure that all relevant enterprise categories have been ticked. For livestock enterprises, also ensure that a system type has been selected from the drop-down menu on this page. Then save your changes and view results again.
Q. G3. Why are my emissions showing as negative?
If feed ration data has not been entered for pigs or poultry nitrous oxide from grazing deposition, manure management and organic manure input to soil will show as a negative in the resource use and emission results.
If the total weight of purchases is greater than the total weight of sales in a given year, the carbon footprint will be negative due to a negative net output. To interpret the results, focus on the KPIs.
Q. L1. Homegrown feed use per cow or ewe is not showing in the enterprise reports.
A. L2. This could be because no crops (other than grazed grass) were fed or an entry was omitted in the “Fed or Used for Bedding” data input field.
Q. E1. Why are my energy emissions showing as zero?
A. E2. Check that the quantities entered in the whole farm data entry box have been allocated to the various enterprises and crops. The calculate button should be used to do this if enterprise level data is not available. If energy use is only entered in the whole farm data entry box, the emissions will not be calculated.