Corn and tomatoes were grown in the greenhouses in boxes containing three horizontal soil zones with a layer of coarse quartz sand to separate the zones. Either fresh or saline waters were supplied to each soil zone through porous ceramic tubes to maintain a fairly uniform water suction in each zone. Intro duction of saline water into a given zone caused the uptake of water by the plant from that zone to decrease as soil salinity increased to a critical value, at which point water uptake ceased. The amount of water taken up by the plant from the nonsaline zones increased so that the total amount of water taken up by the plants was slightly less where onethird of the soil was salinized as compared with the nonsalinized treatment. Water uptake further decreased where twothirds of the root system was salinized. Plant growth was unaffected when one third of the root system was salinized, and yields were only slightly decreased when twothirds of the root system was salin ized. Excessive salinization of the surface soil did not affect water uptake. Water uptake by tomatoes was more affected by zonal salinization than was corn.

Synopsis There were significant reductions in yield for all crops with increasing salinity. With the exception of beet tops and broccoli tops, reductions in yields were significantly less when salinized at more mature growth stages. Tomato tops and pepper tops were the only crops tested which showed a significant interaction between growth stage and salinity

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Synopsis Growth response was obtained only where P was added, and yields decreased with increasing salinity. For a given salinity level, yields were much higher where fertilized with P. Evapotranspiration per unit dry weight of leaves was reduced by P fertilization and decreased with increasing salinity on the P, K and PK treatments. Plant composition generally reflected the cation composition of the soil solution.

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