ProCrop 1999

CROP TOLERANCE

Crops have different tolerance levels for salt concentrations. All crops have a maximum salt level they can tolerate without a yield loss. Salt levels above a crop's maximum tolerance level sharply reduce yields.

The generally accepted soil salinity ratings for field crops, pasture and hay grasses and vegetables are shown in Tables 2 through 4, respectively. The tables show tolerance levels for both 1:1 soil to water slurry as well as saturated paste extracts.

This information is from established plants. As shown in Table 1, crops are often more sensitive at germination and early crop growth. Some varieties within each crop are more tolerant to salt than others. Local agronomists and seed suppliers can help select the best varieties. The percent of decrease in yields for each dS/m above the saturated paste extract maximum tolerance level for each crop is listed. Also, the saturated paste extract level which would give 70 percent of maximum yield was also calculated and listed.

The crops listed in Tables 2 through 4 have also been grouped into the four tolerance groups; 1)sensitive, 2) moderately sensitive, 3) moderately tolerant and 4) tolerant. This tolerance grouping has been used by several researchers as a management aid for growers on saline soils.

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