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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #308005
Title: Phosphorus and nitrogen co-limit global grassland productivity

Author
item Fay, Philip
item PROBER, SUZANNE - Commonwealth Scientific And Industrial Research Organisation (CSIRO)
item HARPOLE, W. - Iowa State University
item KNOPS, JOHANNES - University Of Nebraska
item BAKKER, JONATHAN - University Of Washington
item BORER, ELIZABETH - University Of Minnesota
item MACDOUGALL, ANDREW - University Of Guelph
item SEABLOOM, ERIC - University Of Minnesota
item WRAGG, PETER - University Of Minnesota
item LIND, ERIC - University Of Minnesota

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2014
Publication Date: 12/15/2014
Citation: Fay, P.A., Prober, S.M., Harpole, W.S., Knops, J.M., Bakker, J.D., Borer, E.T., MacDougall, A.S., Seabloom, E.W., Wragg, P.D., Lind, E.M. 2014. Phosphorus and nitrogen co-limit global grassland productivity. In: Proceedings of the American Geophysical Union Fall Meeting, December 15-19, 2014, San Francisco, California.

Interpretive Summary:

Technical Abstract: Terrestrial ecosystem primary productivity has been considered to be primarily nitrogen (N) - limited, but may be co-limited by phosphorus (P), and possibly by potassium and micronutrients (K+m). The frequency, magnitude, and global extent of single or multiple nutrient limitations are poorly understood in natural systems, but can influence how anthropogenic nutrient enrichment affects ecosystem productivity and provisioning of ecosystem goods and services. We examined the occurrence and magnitude of nutrient limitation of aboveground net primary productivity (ANPP) by N, P, and K+m at 42 grassland sites on five continents in the Nutrient Network (https://www.nutnet.umn.edu). N, P, and K+m were factorially applied annually in a randomized block design at all sites. ANPP was measured annually for 3 to 5 years by clipping and weighing standing aboveground biomass. We found clear evidence for nutrient limitation of ANPP in these grasslands. Across all sites and years, the combined addition of N and P increased ANPP by 39% over controls, more than occurred if either was added alone (N: 18%; P: 9%), suggesting co-limitation of ANPP by both nutrients. Co-limitation by other nutrient combinations was not detected. At individual sites, ANPP limitation was most often alleviated by adding N and P together, but K+m addition alleviated ANPP limitation at three sites. Also, site-level limitation of ANPP by any one nutrient was positively correlated (R2 0.07 to 0.21) with limitation by other single or multiple nutrients, suggesting generalized multiple nutrient limitation. We found no differences in nutrient limitation of ANPP among continents or management practices, between native and previously cultivated grasslands, or with site soil properties or climate. These novel patterns of nutrient limitation of ANPP in grasslands around the global contradict the long-held idea that N is the primary nutrient limiting productivity in these ecosystems. Grasslands are globally important, accounting for a third of Earth’s net primary production. Anthropogenic enrichment of grasslands with N or P will likely render ANPP increasingly P, K+m, or multiple-nutrient limited, with consequences for grassland ecosystem services provision.