Management of Salt-Affected Soils - Practices of Irrigation and On-farm Water Management - page 298

Table 8.9 Relative tolerance of annual field crops and forages

Electric conductivity
(dS/m) Annual crop Forage crop

Nonsaline to slightly
saline (0-4)

Soybeans, field beans, fababeans,
peas, corn

Red clover, alsike, timothy

Moderately saline (4-8) Canola, flax, mustard, wheat, oats Reed canary, meadow fescue,
intermediate wheat, crested
wheatgrass, alfalfa, sweet clover

Severely saline (8-16) Barley may grow but forages are

more productive in severe
salinity

Altai wild ryegrass, Russian wild
grass, tall wheatgrass, salt
meadow grass

very tolerant, able to grow on soils with exchangeable sodium percentages above
50%.
Sensitive crops, such as pinto beans, cannot be managed profitably in saline soils.
Table 8.9 shows the relative salt tolerance of field, forage, and vegetable crops. The
table shows the approximate soil salt content (expressed as the electrical conductiv-
ity of a saturated paste extract (EC e ) in dS/m at 25 ◦ C) where 0, 10, 25, and 50%
yield decreases may be expected. Actual yield reductions will vary depending upon
the crop variety and the climatic conditions during the growing season. Fruit crops
may show greater yield variation because a large number of rootstocks and varieties
are available. Also, stage of plant growth has a bearing on salt tolerance. Plants
are usually most sensitive to salt during the emergence and early seedling stages.
Tolerance usually increases as the crop develops. The salt tolerance values apply
only from the late seedling stage through maturity, during the period of most rapid
plant growth. Crops in each class are generally ranked in order of decreasing salt tol-
erance. Even though many field crops do not grow well in saline soil there are other
cropping options, such as forages, that will grow well. Crop selection is a valuable
tool in a salinity management program.
Sunflower is moderately sensitive to soil salinity, where it can tolerate salinity
upto EC equals to 1.7 dS/m. Cotton can tolerate higher salinity levels than some
other crops.

8.5.3 Use of Saline Water for Crop Production

Supplies of good quality irrigation water are expected to decrease in the future.
Thus, irrigated agriculture faces the challenge of using less water, in many cases
of poorer quality. The water having salinity and sodicity may require only minor
modifications of existing irrigation and agronomic strategies in most cases, there
will be some situations that require major changes in the crops grown, the method
of water application, and the use of soil amendments.