Avoiding irrigation
The development of certain pests can be favored by an excess of irrigation of the crop in place. Better irrigation management (see "Irrigate by maximizing water use efficiency") will therefore help limit damage.
The decision not to irrigate a crop can be tactical or strategic (no equipment on the farm, no access to water…).
Points of attention
- The yield of crops whose water needs coincide with periods of low rainfall (summer crops) can be strongly penalized "dry". This phenomenon can be accentuated on soils with low available water capacity.
- The impact of dry management of a crop on yield is directly correlated to the annual climatic context (rainfall).
Effects on the sustainability of the cropping system
"Environmental" criteria
Effect on air quality :
- Phytosanitary emissions : Neutral.
- GHG emissions : Decrease.
Effect on water quality :
- N.P. : Variable.
- Pesticides : Decrease.
Effect on fossil resource consumption :
- Fossil energy consumption : Decrease.
Not irrigating avoids fuel consumption related to irrigation implementation (pumping, moving reels…).
Pollutant transfer to water (N, P, phyto ...): Variable.
Not irrigating can help avoid nitrate leaching or phosphorus and pesticide residue runoff transfers caused by excess irrigation. However, if water deficit does not allow achieving the targeted yield, the residual mineral nitrogen present in the soil at the start of winter may imply increased leaching risks during the drainage period.
Pollutant transfer to air (N, P, phyto ...) : No effect (neutral).
GHG emissions : Decrease. Not irrigating avoids fuel consumption and greenhouse gas emissions related to irrigation implementation (pumping, moving reels…). Moreover, dry management of crops avoids nitrous oxide emissions linked to surface anoxia caused by excess irrigation.
"Agronomic" criteria
Productivity : Decreasing. The effect of not irrigating on crop yield depends on:
- crop sensitivity to water stress,
- available water capacity,
- the annual climatic context (rainfall).
Generally, the effect is neutral in situations where irrigation would not have been justified.
Soil fertility : No effect (neutral).
Water stress : Increasing.
Functional Biodiversity : No effect (neutral).
"Economic" criteria
Operating costs : Decreasing.
Not irrigating a crop, when decided in advance, should lead to reviewing all elements of the technical itinerary: seeding density, nitrogen dose… in line with the targeted yield objective.
Mechanization costs : Decreasing.
Not irrigating avoids mechanization costs related to irrigation: fuel costs related to pumping, moving reels… or even depreciation of irrigation equipment if the decision not to irrigate leads to not investing (or reinvesting) in equipment.
Margin : Variable. The effect of not irrigating on profitability depends on the effect on yield, cost reductions allowed, or even subsidies that may be obtained.
"Social" criteria
Working time : Decreasing.
Not irrigating avoids the workload related to irrigation.
Learn more
Keywords
- Pest control method : Cultural control.
- Mode of action : Mitigation.
- Type of strategy regarding pesticide use : Redesign.
Contacts
Estelle Meslin - INRA - estelle.meslin@rennes.inra.fr - Rennes (35). Rémy Ballot - INRA - remy.ballot@grignon.fr - Grignon (78).
