Effects of drainage salinity evolution on irrigation management

摘要: [1] A soil physics theory of solute movement through a drained saturated zone underlying agricultural land is introduced into long-term economic analysis farm-level irrigation management; this an alternative to the immediate, homogeneous blending assumption employed in previous studies as base for calculating changes drainage salinity over time. Using data from California, effect evolution analyzed year-by-year profit optimization under requirement on-farm disposal. Paths optimal allocation among crop production with fresh surface water, saline reuse and evaporation ponds appear depend on relative profitability first two; that affected by trend salinity. Tile spacing environmental regulations associated affect timing pond construction. The system converges solution involving both drainage-disposal activities; includes outlet salts therefore sustainable. Following strategy, asymptotically approaching steady state possesses hydrological salt balances. Economic implications retirement programs California are discussed.