Work

Responses of soil carbon, nitrogen, and phosphorus stoichiometry to afforestation of severely desertified land in northern China

Year: 2025

Type: article

Abstract: • Two sand fixing tree species in severely desertified land were tested. • Afforestation increases understory herbaceous biomass and diversity. • Afforestation increases soil organic carbon concentration and nitrogen:phosphorus ratio. • Afforestation exacerbates the phosphorus limitation of severely desertified grasslands. • Soil physical properties and vegetation regulate soil carbon, nitrogen, and phosphorus stoichiometry. Large-scale afforestation is being implemented globally to promote carbon sequestration in ecosystems, address climate change, and restore degraded ecosystems. However, the impacts of trees and shrubs on soil stoichiometry in severely desertified land remain unclear. We investigated the topsoil (0 − 20 cm) carbon, nitrogen, and phosphorus (C:N:P) stoichiometry of Pinus sylvestris var. mongolica and Caragana microphylla plantations established on mobile sand dunes in northern China. Soil organic carbon (SOC, 2.6 to 11.3 g kg −1 ) and total nitrogen (TN, 0.3 to 1.2 g kg −1 ) concentrations increased by 3.2 to 6.5 times the values in mobile dunes, on average, after 40 years of afforestation. Total phosphorus (TP, 0.1 to 0.2 g kg −1 ) in the 40-year-old P. sylvestris and C . microphylla plantations increased by 15.1 and 24.3 %, respectively. Well-constrained C:N ratios (7.7 to 10.1 on average) indicated strong coupling relationship between SOC and TN. The average C:P (7.2 to 43.8) and average N:P (0.8 to 4.4) ratios increased with increasing afforestation age due to disproportionate changes in the three elements, but the rate of increase under C. microphylla decreased. N:P ratios under P. sylvestris increased with increasing afforestation age, indicating that long-term P. sylvestris afforestation may become P-limited. Environmental factors explained 75 % of the total variation of soil C:N:P stoichiometry. The improved plant diversity, productivity, and soil physical properties after afforestation improved the soil C:N:P stoichiometry. Climate and terrain had negative impacts on this stoichiometry. We suggest combining multiple species for afforestation to improve species diversity and providing supplemental P in later stages of afforestation to counteract the future P limitation. Our findings provide new knowledge on the relationships between afforestation and soil stoichiometry in severely desertified areas, and provide a reference for optimizing afforestation.

Source: Ecological Indicators

DOI: 10.1016/j.ecolind.2025.113520

Authors: Yuqiang Li, Wenjie Cao, Yun Chen, Libing Han

Institutions: Chinese Academy of Sciences, Ministry of Natural Resources, Northwest Institute of Eco-Environment and Resources, University of Chinese Academy of Sciences, Yunnan Normal University

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Climate action, Life on land

Open Access status: gold

Estimated APC paid: $3,650