Irrigation with diluted seawater would be an
alternative water resource which can play an important
role under scarce resources of freshwater for promoting
agricultural production in coastal areas.
Salvadora persica
Linn. was irrigated with different concentrations of seawater
(0, 10, 20, 40, 60, 80 and 100 % seawater), and
their effect on plant growth, nutrient contents in soil and
plants, shift in soil microbial community structure
(phospholipid fatty acid; PLFA) and community-level
physiological profiling (CLPP, Biolog ECO MicroPlate)
were studied. Plant dry matter was significantly increased
with all seawater treatments, and highest increase was at
20 % seawater treatment. Sodium and chloride contents
were significantly increased, whereas ratios of K/Na and
Ca/Na were significantly decreased in plants with seawater
irrigation. Soil electrical conductivity (EC), available
K and Na were significantly increased with
increasing the concentration of seawater. Total PLFA
concentration and PLFA profile of soils were used as
indices of total microbial biomass and community composition,
respectively. The concentrations of total PLFA,
gram-positive, gram-negative and actinomycetes biomarker
PLFAs were significantly reduced at 20, 40, 80
and 40 % concentrations of seawater, respectively. The
application of different concentrations of seawater
induced a clear shift in the soil microbial community
structure toward the bacterial abundance. The microbial
community structure and community-level physiological
profiling in seawater irrigation treatments had significantly
differentiated. It can be concluded that irrigation
with different concentrations of seawater had significant
impact on soil chemical and microbial properties which is
attributed due to the salinity stress.
