What is an ACI?

In order to illustrate the new climatic conditions in which plants and animals will have to evolve locally, the climatic variables are reworked in such a way as to target potential constraints (detrimental to physiological functioning) or conversely new climatic opportunities. We then speak of agro-climatic indicators, revealing the evolution of “climate pressure” by comparison between a reference period and a future period.

Example of constraints:

high temperatures, characterized by a number of days when the maximum temperature is above 25°C at the end of the development cycle of straw cereals (soft wheat in particular), cause a defect in grain growth and therefore limit the final yield.

Example of opportunity:

the trend increase in the average temperature makes it possible to exploit a higher thermal potential, allowing for example to envisage the success of a catch crop between two main crops.

ACIs already predifined in CANARI

In order to simplify the ACI approach by crop, it can be estimated that the following four major climatic events are likely to affect the yield of the main crops (annual, perennial): water deficit, excess water, high temperatures and low temperatures. Similarly, the intervention of extreme and occasional climatic phenomena (hail, late frost, storm, etc.) will cause yield losses. Each culture corresponds to periods of interest during which stress can have an impact. Knowledge of the physiology of crops and the associated climatic stresses will make it possible to determine the ACIs of interest for each crop.

Multiple ACIs calculations are therefore possible depending on the production orientations of each farm. Most of the time, the ACIs will seek to illustrate similar changes, for example the stress linked to the increase in the number of hot days. However, the periods of interest and/or the temperature thresholds may need to be adjusted according to the productions in which one is interested or even the geographical area considered.

In order to help users identify the possibilities of calculation in terms of ACI, CANARI offers indicators organized by theme:

General indicators not specific to a crop or sector:

average/maximum/minimum temperature, thermal amplitude, temperature sum, number of hot/cold days, etc.
cumulative rainfall, number of days of intense rain, cumulative water deficit, etc.
accumulation of radiation, average wind speed, etc.

Indicators specific to a crop or sector (non-exhaustive list):

indicators specific to straw cereals (wheat, barley, triticale, etc.) targeting in particular the risks associated with high temperatures, frost and water deficit
indicators specific to crops with a summer cycle (e.g. corn or sunflower) targeting in particular the risks associated with high heat and water deficit
indicators targeting in particular possible difficulties during sowing (low rainfall) and autumn weather conditions (days of frost, water deficit)
indicators adapted to grain legumes and targeting the risks associated with high heat and water deficit
indicator concerning grassland fodder areas, and targeting the dates of recovery (grassing, mowing) and the risks of water stress at different seasons
indicators targeting the sensitivity of cattle to heat waves, as well as the heating and ventilation needs of closed livestock buildings (pigs, poultry)
indicators targeting the evolution of thermal availability (link with the choice of grape varieties), the evolution of the freshness of pre-harvest nights (link with wine quality), or the risks of late frost and stress water during the development cycle

Each of the ACI proposed in CANARI remains adjustable by the user, whether for the period or the calculation threshold.

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