Irrigation planning with a field water balance

Irrigation is not decided by rainfall alone

After a short shower the surface can look wet while deeper root-zone layers stay dry. The reverse also happens: the top few centimetres dry out while usable water remains lower down. Timing therefore cannot be read from a single daily rainfall figure.

Meteon’s water balance combines rainfall, reference evaporation, estimated soil properties and root-zone depth. The output tracks usable water and flags when stress thresholds approach, and how forecast rain may change the balance.

Four checks before you start irrigating

1. Rainfall that actually reached the field. In showery weather a nearby station and an on-site gauge can differ a lot.
2. Evaporative loss. High temperature, strong wind and dry air quickly cut usable water.
3. Rooting depth of the stand. Shallow roots reach a smaller store, so stress shows up earlier.
4. Soil intake capacity. On heavy or compacted soils, applying too fast causes runoff and ponding.

From estimate to field decision

The signal shows which field and zone to check first. When deficit rises, inspect soil at the real rooting depth together with morning turgor and the next days’ rain chances.

The irrigation module does not replace water-rights, equipment or agronomic rules — the number is an estimate. Method detail is in the water-deficit guide.