Effects of simulated nitrogen deposition and phosphorus addition on the physicochemical properties and CO2 emissions of Cunninghamia lanceolata
In order to investigate the effects of simulated nitrogen deposition and phosphorus addition on CO2 emission fluxes of Cunninghamia lanceolata soil,two-year-old C.lanceolata was used as the study object.Static box gas chromatography was used to measure CO2 fluxes of C.lanceolata soil under different nitrogen and phosphorus addition treatments,and its relationship with physical and chemical properties,environmental factors and microbial biomass were analyzed.The results showed that the addition of N and P could increase the soil moisture content and soluble organic carbon content of C.lanceolata.The addition of N could increase the contents of NH4+-N and NO3--N to varying degrees,and the addition of P increased the content of available P in soil.Nitrogen and phosphorus addition treatments increased soil CO2 emission fluxes.When nitrogen and phosphorus addition concentrations were 120 kg·hm-2 and 40 mg·kg-1,the CO2 emission fluxes were 82.06 and 92.39 mg·m-2·h-1,respectively,increasing by 5.61%and 18.91%compared with the control treatment.The cumulative CO2 emissions in C.lanceolata soil were significantly correlated with soluble organic carbon and temperature(P＜0.05),and highly correlated with water content(P＜0.01),while there was no correlation with NH4+-N,NO3--N,MBC and MBN(P＞0.05).
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