Management of Salt-Affected Soils - Practices of Irrigation and On-farm Water Management - page 313

Crop Choice/Growing Salt Tolerant Crop Species or Cultivar
Although several treatments and management practices can reduce salt levels in
the soil, there are some situations where it is either impossible or too costly to
attain desirably low soil salinity levels. In some cases, the only viable management
option is to plant salt-tolerant crops. Sensitive crops, such as pinto beans, cannot be
managed profitably in saline soils.
Selecting salt-tolerant crops may be needed in addition to managing soils. Crop
selection can be a good management tool for moderately saline soils. Determination
of appropriate crops for irrigation should be done on the bases of the salt tolerance of
the crop and the salinity of the irrigation water. We have to realize that management
practices, irrigation water quality, and environment also affect tolerance. Just as
crops differ in tolerance to high salt concentrations, they also differ in their ability
to withstand in high sodium concentrations.
Appropriate/Well Adjusted Fertilization
It is important to have good fertility management for the crops grown to have a better
chance of successful stand/establishment. Well-adjusted fertilization could improve
the yields of crops. There have been only a limited number of studies on the effect of
salinity on the nutrition of crops in respect of micronutrients. A disturbed balance
in the uptake and composition of major nutrients is bound to influence the plant
composition of micronutrients. Besides the generally known toxic effects of boron,
there is a need to understand better the behavior of Fe , Mn , Zn , Cu , etc., in relation
to soil salinity particularly with a view to establishing limiting values - so far only
developed for normal soils.
High salinity may interfere with the growth and activity of the soil's microbial
population and thus indirectly affect the transformation of essential plant nutrients
and their availability to plants.
In saline soils, the availability of P is more a function of plant root length and area
(which is restricted due to salinity) and the negative effect of excess chlorides on P
absorption by roots. Application of judicious quantities of P-fertilizers in saline soils
helps to improve crop yields by directly providing phosphorus and by decreasing the
absorption of toxic elements like Cl .
On moderately saline soils, the application of potassic fertilizers may increase the
crop yields either by directly supplying K or by improving its balance with respect
to Na , Ca, and Mg . However, under high salinity conditions it is difficult to exclude
Na effectively from the plant by the use of K -fertilizers.
8.6.2.8 Developing/Cultivating Salt Tolerant Crops
Breeding program should be launched to develop/screen salt tolerant crop culti-
vars. International Rice Research Institute (IRRI) and other international/national
institutes have developed several rice and other crop genotypes, which can tolerate
salinity up to certain level (8-14 dS/m soil or irrigation water EC).