The relationship between crop yield and seasonal amount of applied water (crop‐water production function) is required to determine optimum irrigation management. A model is developed for the computation of crop‐water production functions with saline irrigation waters. The model combines three relationships: yield and evapotranspiration, yield and average root zone salinity, and average root zone salinity and leaching fraction. The model allows plant growth adjustment, and therefore evapotranspiration adjustment, to root zone salinity. Crop‐water production functions were computed for tall fescue (Festuca elatior arundinacea L.) for various levels of salinity in the irrigation water. A comparison was made between calculated and published experimentally measured values of leaching fractions and yields of tall fescue grown under conditions of various irrigation water salinities, water application quantities and applied water frequencies. Calculated and measured yields were in good agreement considering the usual degree of variability of field data. Agreement between calculated and measured leaching fractions was not as good as for yields.

ater an gement: tribution I UNIVERSITY OF Empirical estimates of benefits from groundwater management are reported for an ar a in) California with heavy reliance on groundwater supplies. Benefits are quite sensitive t hi the water demand schedule and interest rate but less sensitive to other parameters. I However, in all cases considered the increases in welfare from groundwater managlentAg ' ricuitura I rc n n o riirs Lib''' rv are less than ten percent. Tax revenues received under a system of pump taxes are foil? to five times as large as the benefits from management. Thus, groundwater users gain under a system of quotas but may suffer substantial welfare losses under pump taxes.

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Salinity and drainage management options include source control, reuse, and evaporation ponds. This article identifies efficient strategies to maintain hydrologic balance in closed drainage basins and evaluates their impact on regional agricultural profits. Theoretical analysis suggests that economic efficiency requires acknowledgment of the nonseparability between water use and land value. Empirically, our solution involves a modest amount of source control, a substantial amount of reuse, and the elimination of evaporation ponds often associated with large environmental damages, while maintaining grower income. Various policy instruments and options are introduced and discussed, including a system of drainwater charges, marketable permits, and land retirement.