Pedosphere 35(4): 678--689, 2025
ISSN 1002-0160/CN 32-1315/P
©2025 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Vermicompost maintains topsoil fertility by reducing NH3 volatilization and improving 15N/NO3- retention in a saline-alkali soil |
Siping LI, Chong WANG , Huiying HUANG, Jia CAO, Rui XUE, Binglei WANG |
| State Key Laboratory of Nutrient Use and Management, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China) |
| ABSTRACT |
| Nitrogen (N) loss is a major limiting factor affecting agricultural productivity in saline-alkali soils, with ammonia (NH3) volatilization and N leaching being the main sources of N loss. In this study, the dynamics of NH3 volatilization were measured using the open static chamber method (sponge sampling), alongside the distribution of 15N and NO3--N concentrations in layers, in a 30-cm soil column experiment with vermicompost addition after incorporation of 15N-labeled urea in the upper layer (0-10 cm) of a saline-alkali soil. Destructive sampling was conducted on days 20 and 60 of the column experiment to investigate the influencing factors of NH3 volatilization and 15N/NO3- retention, respectively. The results showed that the addition of vermicompost to saline-alkali soil decreased cumulative NH3 volatilization by 45.1%, decreased the 15N concentration in the bottom layer (20-30 cm) by 17.1%, and increased the 15N concentration in the upper soil by 48.7%. Vermicompost regulated the abundances of amoA, amoC, and nxrA genes, which can decrease NH3 volatilization by converting substrate NH4+ to NO3-. Additionally, Ca2+ adsorption is enhanced (increased by 6.2%) by increasing soil cation exchange capacity (increased by 20.6%), thus replacing the adsorption of Na+ (decreased by 13.8%) and decreasing the desorption of NH4+. Vermicompost enhanced the adsorption of NO3- by increasing Ca2+ and Mg2+ and decreasing Cl- by 30.4% in the upper soil. This study concluded that vermicompost addition can inhibit N loss by reducing NH3 volatilization and improving 15N/NO3- retention in saline-alkali soils. |
| Key Words: N-cycling genes,N loss,ion balance,isotope tracer technology,macrogenome sequencing,soil aggregation,soil salinization |
| Citation: Li S P, Wang C, Huang H Y, Cao J, Xue R, Wang B L. 2025. Vermicompost maintains topsoil fertility by reducing NH3 volatilization and improving 15N/NO3- retention in a saline-alkali soil. Pedosphere. 35(4): 678-689. |
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