Monthly Net Irrigation Requirements (NIR) in mm have been calculated for all crop_groups , agro-climatic zones and the 3 hydrological year types with a special NIR preprocessing module. They take not only account of the Penman evapotranspiration but also of effective rainfall.
Because of the different way plant roots are developing under drip irrigation, NIR distinguishes between drip irrigation on the one hand and other irrigation (sprinkler and surface).
The pre-calculated results are stored in table YEAR_TYPE_NIR, thus NIR do not need to be calculated in the irrigation module.
Data Table YEAR_TYPE_NIR (top records only):
Table YEAR_TYPE_NIR is very large; in order to speed-up the calculation, after the selection the relevant records copied into table selected_YEAR_TYPE_NIR.