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United States Department of Agriculture

Agricultural Research Service

Research Project: Crop Response to Wastewater Irrigation As Related to Water Salinity and Ion Composition
2013 Annual Report


1a.Objectives (from AD-416):
Characterize and evaluate varietal differences for selected crops, as related to salinity and irrigation water composition.


1b.Approach (from AD-416):
Conduct greenhouse lysimeter and field studies to determine relative response and yield of a number of varieties of high value salt sensitive corps.


3.Progress Report:

This research is covered under objective 1, "Identify variability in physiological and biochemical response mechanisms associated with the use of saline waters on cultivars of selected agronomic or horticultural salt-sensitive crops and develop strategies to mitigate the negative effects of salts and toxic ions by making more effective use of the waters for crop production". In this project, we are examining variability in the response of alfalfa population to elevated salinity and the variability of tomato response to saline waters as related to grafting and water composition.

We completed a greenhouse alfalfa experiment using 15 genotypes, salinity levels and two different water qualities. We evaluated plants grown under water compositions typical of interior continental inland valleys (such as the Central Valley of California), as well as waters more representative of coastal saline regions. We did not see differences in yield related to these two different water types, thereby indicating that this factor is not critical to representing alfalfa tolerance to salinity. We found significant differences in alfalfa genotype response to salinity and have selected several genotypes for further salt tolerance evaluation.

We established, in a greenhouse study, that grafted tomato plants had greater yield under both non-saline control conditions as well as under saline conditions. We examined the impact of water composition as well as salinity on marketable fruit yield (mass) fruit size, number of fruit and shoot and fruit ion composition. Our data indicate that for tomato, decreased yield under saline conditions is well related to increased leaf sodium concentrations. However, grafted plants had reduced leaf sodium contents relative to non-grafted plants at all salinity levels. Increased solution chloride was not related to changes in yield, suggesting that yield reduction from chloride ion toxicity is not a consideration for tomato. Additionally, grafted plants had increased yield but slightly higher leaf chloride concentrations as compared to non-grafted plants, again indicating that chloride ion concentration was not a factor in yield loss under saline conditions. Grafting is recommended as an option to increase tomato yield regardless of irrigation water salinity.


Last Modified: 8/19/2014
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