Effects of seawater irrigation on soil microbial community structure and physiological function

Abstract

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.

Effect of Irrigation Water Salinity on Soil Characteristics and Microbial Communities in Cotton Fields in Southern Xinjiang, China

“…This may be attributed to alterations in the makeup of the microbial community in the long-term saline stress environment, and the salt-tolerant microorganisms had a better living environment under the BWI treatment conditions, resulting in higher MBC, MBN, urease, and sucrase contents in the BWI treatment. Microorganisms are the main providers of soil enzymes under stress from saline irrigation, with a consequent decrease in soil enzyme synthesis [48,49]; however, the BWI treatment in this study had the highest bacterial and fungal richness and, therefore, the BWI had higher enzyme activity. Zahran [50] also noted that the activity of soil enzymes produced by salt-tolerant bacteria is higher than the corresponding activity of soil enzymes produced by non-salt-tolerant bacteria, so higher soil enzyme activity may still be present in the soil even under high-salinity water irrigation conditions.…”

“…This may be attributed to alterations in the makeup of the microbial community in the long-term saline stress environment, and the salt-tolerant microorganisms had a better living environment under the BWI treatment conditions, resulting in higher MBC, MBN, urease, and sucrase contents in the BWI treatment. Microorganisms are the main providers of soil enzymes under stress from saline irrigation, with a consequent decrease in soil enzyme synthesis [48,49]; however, the BWI…”