Effects of Nitrogen and Phosphorus Additions on Soil N2O Emission and Soil Carbon Storage in Lakeshore Zone

This study examined the short-term effects of nitrogen (N) and phosphorus (P) addition on soil N2O flux and organic carbon content in the lakeshore zone of an arid inland lake, Daihai. Treatments included control (N0P0), N addition (N1P0), P addition (N0P1), and NP co-addition (N1P1). Using the static chamber method and lab analyses, we measured soil N2O flux and organic carbon content at different growth stages. Results showed that, in the early growing season, short-term N and P addition had no significant effect on soil N2O flux, with all treatments acting as N2O sources. However, N and NP treatments significantly increased soil organic carbon (SOC) storage, improving carbon sequestration benefits by 72.7% to 98.1%. During the peak growing season, N and NP treatments significantly enhanced soil N2O emissions, while NP treatment further increased SOC storage, the carbon sequestration benefits of all treatments ranging from 49.0% to 56.5%. At the late growing season, N and P addition had no significant impact on soil N2O flux or organic carbon storage, with all sites acting as N2O sinks and SOC storage showing no significant change across treatments (carbon sequestration benefits ranged from 0.3% to 38.5%). The study highlights that the response of soil N2O flux to short-term N and P addition varies at different growth stages, while overall, N and P addition promotes soil carbon sequestration throughout the growing season in the lakeshore zone.