Fecha/hora: 09/06/2024 17:22:57

Biblioteca(s): 	INIA Tacuarembó; INIA Treinta y Tres.	
Fecha corriente: 	02/02/2016	
Fecha de la última actualización: 	10/10/2019	
Autoria: 	JAURENA, M.; LEZAMA, F.; SALVO, L.; CARDOZO, G.; AYALA, W.; TERRA, J.A.; NABINGER, C.	
Afiliación: 	MARTIN ALEJANDRO JAURENA BARRIOS, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; FELIPE LEZAMA, Facultad de Agronomía, UDELAR, UY.; LUCÍA SALVO, Facultad de Agronomía, UDELAR, UY.; GERONIMO AGUSTIN CARDOZO CABANELAS, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; WALTER FELIZARDO AYALA SILVERA, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; JOSÉ ALFREDO TERRA FERNÁNDEZ, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; CARLOS NABINGER, UNIVERSIDADE FEDERAL DE RÍO GRANDE DO SUL, PORTO ALEGRE, RS, BRASIL.	
Título: 	The dilemma of improving native grasslands by overseeding legumes: production intensification or diversity conservation.	
Año de publicación: 	2016	
Fuente/Imprenta: 	Rangeland Ecology & Management, 2016, v. 69, no. 1 p. 35-42.	
ISSN: 	1550-7424	
DOI: 	10.1016/j.rama.2015.10.006	
Idioma: 	Inglés	
Notas: 	Article history: Received 25 November 2014; Accepted 23 September 2015.	
Contenido: 	In native campos of Uruguay, overseeding legumes coupled with phosphorus (P) fertilization is a technology used to increase animal production. Short-termimprovements in both forage productivity and quality are repeatedly reported. However, some evidence suggests that this management may at times lead to the collapse of the native community and invasions by exotic species. Indeed, it is yet unclear to what extent overseeding legumes into native grasslands affects its long-term integrity. This study uses data from a long-term experiment to assess whether increased P fertilizer rates?typically used to encourage legume establishment and growth?are associated with reduced species diversity. In 1996 a grazed native grassland in eastern Uruguay was either left untouched (control) or overseeded with a mix of Trifolium repens and Lotus corniculatus and then fertilized at either a moderate or high rate of P (197 or 394 kg · ha?1 over 13 years, respectively). The three treatments were arranged in a randomized block design with four replicates of 2 hectares each. In 2005 the experiment was exhaustively sampled: 11 georeferenced sampling points per replicate, each encompassing ~20m2. Extractable Pwasmeasured in the 0?5- and 5?15-cmsoil layers. In 2009, species presence and cover weremeasured at the same points. Across treatments,wherever legumes were introduced, extractable soil Pwas negatively related to species richness and diversity (P b 0.01) and native grass cover was reduced. This effect became asymptotic once soil P exceeded 27 and 36 mg · kg?1 of P (0?5 cm), respectively. Therefore the documented reduction in species richness and diversity suggests a trade-off between increased pasture production and decreased vegetation stability may be operating in response to P fertilization of overseeded grasslands. The underlying
ecophysiological mechanisms, as well as grazing management options to mitigate species diversity decline, should be further studied.	
Palabras-Clave: 	CAMPOS; IMPROVEMENT; INTEGRACIÓN A LARGO PLAZO; LONG-TERM INTEGRITY; PRODUCCIÓN A CORTO PLAZO; SHORT-TERM PRODUCTION; TRADE-OF.	
Thesagro: 	INTEGRACION; LEGUMINOSAS; MEJORAMIENTOS EXTENSIVOS; PASTURAS NATURALES; PRODUCCION.	
Categoría del tema: 	F62 Fisiología  de la planta - Crecimiento y desarrollo	
Registro original: 	INIA Tacuarembó (TBO)	
Ejemplares: 	TBO - (101090-1) - PXI - AP - DD - PP/RANGELAND ECOLOGY & MANAGEMENT/69 -  -  - DIS
TT - (101129-1) - PXI - AP - DD - PP/RANGELAND ECOLOGY & MANAGEMENT -  -  - DIS