User's manual

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The future agri-food systems project for a socially and environmentally sustainable transition: co-design of strategies for the mitigation of environmental risks in water and atmosphere in natural areas of the SUDOE territory (AGROGREEN SUDOE) has several objectives, including mitigating the environmental effects or impacts of agronomic practices such as fertilisation and irrigation.

For this reason, and in order to achieve this objective in terms of fertilisation practices, it was decided to work on the creation of a nutrient calculator that can be used by farmers throughout the SUDOE territory.

The nutrient calculator is based on the Farm Sustainability Tool for Nutrients (FaST), developed by the European Commission.

It is therefore a decision-making tool to support farmers in achieving agronomic efficiency and the absence of harmful effects on health and the environment.

This user manual explains how the Agrogreen nutrient calculator works, through the development of four main steps.

How does the Agrogreen nutrient calculator work?

First step. Add the yields.

In the first step of the tool, the user will have to enter a series of very simple data. This involves answering a series of questions, the answers to which will be taken into account in order to offer the fertiliser strategy that best suits the needs and objectives expected by the farmer.

The data to be entered are:

  1. Current campaign:
    • Crop for which the fertiliser recommendation is to be obtained
    • Expected yield for this crop (kg/ha)
  2. Previous campaign:
    • Previous season's crop
    • Yield obtained (kg/ha)
  3. Indication if the parcel is located in an area vulnerable to nitrate contamination.
    • Yes/No
    • Enter the nitrogen (N) unit limit, if known.

Introduction of soil data.

  • No soil test data: In this case, the calculator will give a result of N-P-K units, based on the fertilisation strategy Soil fertility maintenance. Since no information about the nutrients contained in the soil is assumed, the tool will assume by default that there is no constraint to achieve the expected yields.
  • If you have soil analysis data: If you have these data and enter them, the Agrogreen nutrient calculator will be able to give a more accurate result, as it can provide three fertilisation strategies, taking into account the starting data of the soil nutrients.

The soil analysis data to be requested by the tool are as follows:

  1. Type of soil
  2. % organic matter
  3. pH
  4. Parts per million Potassium [ppm (K)]
  5. Parts per million Phosphorus [ppm (P)]
We want to know what you think about the Agrogreen sudoe nutrient calculator. We have prepared a series of questions to improve it, it will take you no more than 2 minutes.

If you want to improve your results or send us feedback on the nutrient calculator, write to us here

Step two. Select a fertilisation strategy

The user will be able to choose the strategy that best suits him/her, in order to achieve his/her crop yield objectives.

Strategy Minimal environmental impact

Environmental impact


This is the strategy that minimises the risk of environmental impact related to fertiliser input, although it may lead to a certain decrease in yield. In practice, this strategy reduces P and K fertilisation to almost 100%, except in very extreme cases. This strategy may cause some problems in the long term, due to the loss of nutrients in the soil.

Maintenance fertiliser strategy.

Environmental impact


This strategy is designed to obtain a return on the fertiliser used and maximum yield in the long term, while greatly limiting the environmental impact of fertiliser inputs.

Strategy Maximum nutrient supply.

Environmental impact


This option prioritises obtaining the highest possible yields, thereby increasing the environmental impact of fertiliser inputs on farming systems.

Each strategy will offer a result in units of N-P-K, which must be selected by the user to continue. In addition, they will be accompanied by a coloured bar (green, yellow and pink) whose legend is linked to the environmental impact of each strategy.

Before moving on to the next interface, a summary of all the data entered by the user will be provided.

  • Previous crop
  • Current crop
  • Soil analytical data

Step 3. Select from used fertilisers

At this stage, the user must select the type(s) of subscription he/she usually wants to use.

Organic fertiliser
Inorganic fertiliser
Nitrogen fertiliser

In order to reach the fertiliser units recommended by the chosen strategy, and depending on how the farmer fertilises, he/she can choose one or several fertiliser types.

Therefore, it will be the case that only one or several fertiliser types are chosen to reach the fertiliser units of the previously chosen strategy.

For any of the chosen options, the tool will offer a diagram, so that the farmer is visually informed if he/she has covered, with his/her decision, the fertiliser units recommended in the fertilisation strategy selected in step 2, or, on the contrary, his/her choice does not reach the recommended fertilisation.


In this last phase, the tool will offer a summary, both of the information entered by the user, and an estimation of the cost of the selected fertiliser, the selected fertilisation strategy, as well as the option (A-F) that the farmer has decided to complete the fertiliser units.

Furthermore, as a differential element of the calculator, additional information will be provided on environmental recommendations and practical issues that can help to reduce the environmental impact of the fertilisation strategy, without affecting the productive potential.

The results will be available as a pdf file. Furthermore, the user is given the possibility to indicate whether he/she will apply the strategy recommended by the calculator.

AgroGreen SUDOE visualisation tool

A journey through the agricultural systems of the SUDOE territory, with a special focus on the Garonne and Tagus river basins.


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