5377 Making Salt-Affected Areas Profitable
Saline agriculture is largely about making better choices for the use of land based
on the capability of the land, the level of production that is possible and the value of
that production.
Land capability is mostly affected by the salinity of the soil solution – the ratio
of salt to water in the soil. However, it can also be affected by the presence of other
stresses such as waterlogging and toxic boron. Nonetheless, here we only focus on
salinity. When considering options for saline land, it is useful to orientate thinking
with a larger framework (Fig. 3 ). Sodium chloride, the most common salt found in
soil forms a saturated solution at about 360 g/L of water. We can therefore think of
the salinity of the soil solution in terms of the percentage of saturation of such a
NaCl solution. No high order plants will survive with salinities of the soil solution
greater than ~40 % of saturation, but halophytes (salt-loving plants) will survive
with salinities less than this level. Seawater salinity occurs at ~9 % of saturation,
and crop plants begin to become economically important at salinities equivalent to
4 % of saturation (Fig. 3 ).
Reviews of international literature on the effects of salinity on the growth of
crops show that increasing salinity decreases the yield of all crops (Fig. 4 ). However,
crop plants can differ widely in their tolerance to salinity, as measured by the salt
concentration (ECe) at which their yield decreases by 50 %. The most salt-sensitive
crop shown in Fig. 4 (strawberry) had a 50 % decrease in yield at an ECe of 2.2 dS
m−^1 , while the most salt-tolerant crop (asparagus) had a 50 % decrease in yield at an
ECe of 28.5 dS m−^1.
Fig. 3 Framework for thinking about the salinities that plants can endure
Salinity in Dryland Agricultural Systems: Challenges and Opportunities