Nitrogen and phosphorus additions alter foliar nutrient concentrations of dominant grass species and regulate primary productivity in an Inner Mongolian meadow steppe

Hong Xiao; Pengzhen Li; Thomas A Monaco; Yuling Liu; Yuping Rong

doi:10.1016/j.scitotenv.2023.168791

Nitrogen and phosphorus additions alter foliar nutrient concentrations of dominant grass species and regulate primary productivity in an Inner Mongolian meadow steppe

Sci Total Environ. 2024 Feb 20:912:168791. doi: 10.1016/j.scitotenv.2023.168791. Epub 2023 Nov 22.

Authors

Hong Xiao¹, Pengzhen Li², Thomas A Monaco³, Yuling Liu², Yuping Rong⁴

Affiliations

¹ College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China; Grassland Ecosystem Key Laboratory of Ministry of Education, College of Pratacultural Science, Gansu Agricultural University, Lanzhou, Gansu 730070, China.
² College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China.
³ U.S. Department of Agriculture, Agricultural Research Service, Forage and Range Research Laboratory, Utah State University, Logan, UT 84322-6300, USA.
⁴ College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China. Electronic address: rongyuping@cau.edu.cn.

PMID: 38000742
DOI: 10.1016/j.scitotenv.2023.168791

Abstract

Excessive nitrogen (N) inputs shift grassland productivity from nitrogen (N) to phosphorus (P) limitation. However, how plant nutrient concentrations and stoichiometric dynamics at community and species level responding to variable soil N and P availability, and their roles in regulating net primary productivity in meadow steppe remain unclear. To address this issue, we carried out an experiment with fifteen treatments consisting of factorial combinations of N (0, 1.55, 4.65,13.95, 27.9 g N m^-2 y^r-1) and P (0, 5.24,10.48 g P m^-2 yr^-1) for three years in a meadow steppe in Inner Mongolia. We examined concentrations and stoichiometry of C (carbon), N, P in plants and soils, and their associations with plant primary productivity. Results revealed mean community N:P ratios for shoots (12.89 ± 0.98) did not exceed 14 within the control treatment, indicating that plant growth was primarily N-limited in this ecosystem. Shoot N:P ratios were significantly increased by N addition (>16 when N application rate above 4.65 g N m^-2 y^r-1), shifting the community from N- to P-limited whereas significantly reduced by P addition (N:P ratios <14), further aggravating N limitation. N addition increased leaf-N concentrations whereas decreased leaf C:N ratios of all four species, but only the values for two graminoid species were significantly influenced by P addition. Leaf-P concentrations significantly increased for graminoids but significantly decreased for forbs with the application of N. VPA analysis revealed that aboveground components, especially in grass leaves, explained more variation in aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) than root and soil components. For grasses, leaf-N concentrations showed high association with ANPP, while leaf-P concentrations were associated with BNPP. These results highlight that N and P depositions could affect the leaf-nutrient concentrations of dominant grasses, and thereby potentially alter net primary productivity in meadow steppe.

Keywords: Meadow steppe; Nitrogen; Phosphorus; Plant productivity; Plant stoichiometry; Soil nutrients.

MeSH terms

Biomass
Ecosystem*
Grassland
Nitrogen / analysis
Phosphorus / analysis
Plants
Poaceae*
Soil

Substances

Phosphorus
Nitrogen
Soil