Salinity Levels Alter Soil Nitrous Oxide Emission,Ammonia Volatilization, and Nitrogen Leaching

Soil nitrogen (N) turnover in saline soils is largely unknown, and investigations of N losses from such soils have yielded conflicting findings.A meta-analysis was thus employed to explore the influence of salinity on soil N 2 O and NH 3 emissions, and N leaching potential (P Nr , the proportion of NO 3 to total inorganic N).Results indicated that increasing salinity significantly increased soil NH 3 emissions, except during experiments longer than 14 d under low salinity (ECe<4-12 dS m -1 ).Salinity effects on soil N 2 O emissions decreased by 30-82% at medium salinity (ECe = 12-16 dS m -1 ) over periods shorter than 14 d, and increased by 90-177% at high salinity (ECe>16 dS m -1 ).P Nr decreased by 36-68% at high salinity.Soil pH, organic carbon, total and inorganic N also had significant influences on N 2 O and NH 3 emissions, and P Nr .Hence, salinity levels have significant direct effects on N losses, simultaneously, indirectly influencing N turnover by altering soil properties.In brief, N losses from saline soils mainly derive from N 2 O and NH 3 emissions, and more attention should be given to understanding the transformation of N forms and the involved mechanisms for better N management in saline soils.