Agricultural hydrology

When the water table is inside the root zone, the balances containing the components Per, Cap are not appropriate as they do not exist.

Vertical hydrological components along the boundary between two zones with arrows in the same direction can be combined into net values .

Equally, they are used in groundwater salinity models like SahysMod which is a spatial variation of SaltMod using a polygonal network.

The irrigation requirement depends on the rooting depth of the crops, which determines their capacity to make use of the water stored in the soil after winter.

Having a shallow rooting system, pastures need irrigation to an amount of about half of the storage depletion in summer.

Practically, wheat does not require irrigation because it develops deeper roots while during the maturing period a dry soil is favorable.

The analysis of cumulative frequency[6] of climatic data plays an important role in the determination of the irrigation and drainage needs in the long run.