03290naa a2200289 a 450000100080000000500110000800800410001902200460006002400360010610000160014224501990015826000090035750006550036652017050102165300340272665300220276065300130278265300270279570000140282270000150283670000140285170000150286570000180288070000160289870000170291477300690293110644982024-03-05       2024    bl uuuu     u00u1 u    #d  a0032-079X (print); 1573-5036 (electronic)7 a10.1007/s11104-024-06562-52DOI1 aCARDOZO, G.  aLimited response to phosphorus fertilization in native South American grasslands across a productivity gradient despite low phosphorus concentrations in grassland herbage.h[electronic resource]  c2024  aArticle history: Received 10 October 2023; Accepted 14 February 2024; Published 26 February 2024. -- Responsible Editor: N. Jim Barrow. --  Correspondence: G.A. Cardozo, Instituto Nacional de Investigación Agropecuaria (INIA), Estación Experimental INIA Treinta y Tres, Ruta 8 km 281, Treinta y Tres 33000, Uruguay. e-mail: gcardozo@inia.org.uy -- Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s11104-024-06562-5 -- Funding: This work was supported by the National Agency for Research and Innovation (ANII-Uruguay) [grant numbers POS_NAC_2016_1_130414 y FSA_PI_2018_1_148653]. --  aABSTRACT.- Background and aims: Since 1750, the species-rich grasslands native to the Río de la Plata basin in southern South America have sustained low-input livestock production. Typically, these grasslands have low herbage phosphorus (P) concentration, and P deficiency in livestock is not rare. Worldwide, P fertilization is used to increase the productivity and nutritive value of grasslands, but it is unknown whether the Río de la Plata grasslands are limited by P availability. -- Methods: We quantified the response of aboveground net primary productivity (ANPP) to P supply in a meta-analysis of 39 trials carried out between 1968 and 2016 comprising 285 independent comparisons (cases) between unfertilized controls and P-fertilized treatments. -- Results: The ANPP of unfertilized controls ranged from 400 to 17,500 kg dry matter (DM) ha-1 y-1. In 74% of cases, P fertilization did not increase ANPP. The average response was therefore low, at 399 kg DM ha-1 (relative effect + 15%), and largely unrelated to ANPP, vegetation, or soil characteristics. Conversely, in 59% of cases herbage P concentration did increase, particularly at high fertilization rates (average 0.43 mg P g DM-1; relative effect + 36%). -- Conclusions: Despite low herbage P concentration, the current ANPP of Río de la Plata grasslands seems little limited by P supply. Luxury consumption was common in response to P fertilization. Prevailing low herbage nitrogen-to-phosphorus ratios -below 11:1 in 65% of unfertilized controls- suggest nitrogen may be limiting ANPP. In this legume-scarce ecosystem, P fertilization is unlikely to boost productivity and may pose an environmental risk. © 2024 Springer Nature  a"Río de la Plata" grasslands  aForage production  aNitrogen  aStoichiometric changes1 aAYALA, W.1 aLEZAMA, F.1 aREYNO, R.1 aCUADRO, R.1 aMICHELINI, D.1 aJAURENA, M.1 aLATTANZI, F.  tPlant and Soil. 2024. https://doi.org/10.1007/s11104-024-06562-5