Effect of Salinity on Soil Respiration and Nitrogen Dynamics

Abstract

A facility of BaPS (Barometric Process Separation) and indoor incubation experiments were used to determine the effect of soil salinity on soil respiration and nitrogen transformation. The rates of soil respiration, gross nitrification, denitrification, ammonium and nitrate nitrogen concentrations and relevant soil parameters were measured. Results showed that soil respiration and nitrification and denitrification rates were all affected by soil salinity. Furthermore, the effect of soil salinity level on nitrification and denitrification rates had a threshold value (EC1:5 = 1.13 dS/m). When soil salinity level was smaller to this threshold value, the rates of nitrification and denitrification increased with soil salinity while they were reduced when soil salinity level was larger than the threshold value. Moreover, the changing law of soil respiration rate with soil salinity was similar with the nitrification and denitrification rates while the variation tendency was opposite. In addition, the transformation form urea to ammonium and nitrate nitrogen was also reduced with the increase of soil salinity and the reduced effect could be expressed by exponential functions.

Gross nitrogen transformation rates in semiarid tropical soils under different salinity and vegetation conditions

“…Increased salinity can inhibit soil evaporation and hence increase the water content of soils (Zeng et al. , Zhang et al. ), which was also reflected in our study.…”

“…Increased salinity can inhibit soil evaporation and hence increase the water content of soils (Zeng et al 2013, Zhang et al 2013, which was also reflected in our study. Additionally, the coastal salt flat was located at supra-tidal zone where maximum evaporation did not occur due to the difference in moisture between pore water and atmosphere (Geng and Boufadel 2015).…”

“…), salinity threshold (Pathak and Rao , Zeng et al. ), and increased N mineralization (Noe et al. ) due to salinity change have also been reported.…”

“…A number of studies have evaluated the effects of salinity on soil N transformation rates as availability of N is inextricably linked to biological productivity. The majority of these studies have either measured the net rates (Pathak and Rao 1998, Khoi et al 2006, Bai et al 2012 or conducted laboratory experiments with amended salinity (Lodhi et al 2009, Akhtar et al 2012, Zeng et al 2013, Gao et al 2014). In general, these studies indicated a negative effect of salinity on N mineralization (Fang et al 2005, Yuan et al 2007, Lin et al 2016.…”

Microbial and Enzyme Activities and Carbon Stock in Unique Coastal Acid Saline Soils of Goa

“…But, the ranges for urease and phosphatase were found more or less similar. The transformation of urea to ammonium and nitrate nitrogen reduces with the increase in soil salinity [36] and thus it indirectly confirms the depressive effect of the salinity on urease activity. It could be due to the adverse effect of salinity as a shift in microbial population structure, as soil microorganisms have adapted to salinity over a long run [37].…”