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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #370654
Research Project: Contributions of Climate, Soils, Species Diversity, and Management to Sustainable Crop, Grassland, and Livestock Production Systems

Location: Grassland Soil and Water Research Laboratory

Title: Losing the beans: Nitrogen overrides positive effects of phosphorus on grassland legumes worldwide

Author
item TOGNETTI, PEDRO - University Of Buenos Aires
item PROBER, SUZANNE - Commonwealth Scientific And Industrial Research Organisation (CSIRO)
item BAEZ, SELENE - Escuela Agricola Panamericana
item CHANETON, ENRIQUE - University Of Buenos Aires
item FIRN, JENNIFER - Queensland University Of Technology
item RISCH, ANITA - Swiss Federal Research Institute Wsl
item SCHUETZ, MARTIN - Swiss Federal Research Institute Wsl
item SIMONSEN, ANNA - Australian National University
item YAHDJIAN, LAURA - University Of Buenos Aires
item BORER, ELIZABETH - University Of Minnesota
item SEABLOOM, ERIC - University Of Minnesota
item ARNILLAS, CARLOS - University Of Toronto
item BAKKER, JONATHAN - University Of Washington
item BROWN, CYNTHIA - Colorado State University
item CADOTTE, MARC - University Of Toronto
item CALDEIRA, MARIA - Universidade Nova De Lisboa
item DALEO, PEDRO - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET)
item DWYER, JOHN - University Of Queensland
item Fay, Philip
item GHERARDI, LAUREANO - Arizona State University
item HAGENAH, NICOLE - University Of Pretoria
item HAUTIER, YANN - Utrecht University
item KOMATSU, KIMBERLY - Smithsonian Environmental Research Center
item MCCULLEY, REBECCA - University Of Kentucky
item PRICE, JODI - Charles Stuart University
item STANDISH, RACHEL - Murdoch University
item STEVENS, CARLY - Lancaster University
item WRAGG, PETER - University Of Minnesota
item SANKARAN, MAHESH - National Centre For Biological Sciences

Submitted to: Proceedings of the National Academy of Sciences (PNAS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: The Earth’s nitrogen cycle is being critically accelerated by nitrogen escape into the environment from agriculture and transport, and industrial processes. Plants in the pea and bean family, known as legumes, are the primary route by which nitrogen gas from the air enters terrestrial ecosystems through the biological process of nitrogen fixation, ultimately being converted into chemical forms useable in critical life processes. The abundance of nitrogen-fixing legumes is thought to be greater on soils that are poor in nitrogen, and to be further enhanced by increased availability of other important mineral nutrients, especially phosphorus and potassium. This study analyzed data from experiments in grasslands fertilized with nitrogen, phosphorus, and potassium at 45 locations across the globe. The study shows for the first time that legume abundance decreases when fertilized with nitrogen. Furthermore, while fertilization with phosphorus and potassium increased legume abundance, addition of these nutrients did not offset the losses in legume abundance caused by increased nitrogen. Thus, increased nitrogen in the environment from human activities can be expected to further disrupt the basic biological process by which atmospheric nitrogen gas cycles through natural and managed ecosystems.

Technical Abstract: Anthropogenic nutrient deposition is driving global biodiversity decline, altering ecosystem productivity and modifying ecosystem functions. Theory suggests that plant functional types with specialist nitrogen (N)-acquisition strategies will be especially vulnerable to N-deposition, through loss of competitive advantage associated with N-poor soils. By contrast, addition of phosphorus (P), potassium (K) and other nutrients may benefit such species in low nutrient environments by enhancing their N-fixing capacity. We present the first global scale assessment confirming these predictions for N-fixing legumes (Fabaceae), using standardized experiments in 45 grasslands on six continents. Nitrogen addition reduced legume cover, richness, and biomass particularly in N-poor soils, while increasing cover of non-N-fixing plants and decreasing light availability. Addition of P, K and other nutrients enhanced legume abundance, but did not mitigate effects of N addition. Anthropogenic N-deposition is thus likely to decrease the diversity and abundance of grassland legumes worldwide regardless of deposition of other nutrients.