Data/hora: 23/09/2024 20:33:22

Biblioteca(s): 	Embrapa Meio Norte / UEP-Parnaíba.	
Data corrente: 	31/03/1998	
Data da última atualização: 	31/03/1998	
Autoria: 	JENKINSON, D. S.; FOX, R. H.; RAYNER, J. H.	
Título: 	Interactions between fertilizer nitrogen and soil nitrogen - the so-called 'priming' effect.	
Ano de publicação: 	1985	
Fonte/Imprenta: 	Journal of Soil Science, v.36, p.425-444, 1985.	
Idioma: 	Inglês	
Conteúdo: 	<Experiments with l5N labelled fertilizers often show that plants given fertilizer N take up more N from the soi than plants not geiven N - the priming effect or 'added nitrogen interaction' (ANI). This paper is a theoretical study of ANIs and how they can affect the interpretation of experiments with 15N labelled fertilizers. ANIs can be 'real' , if for example,  fertilizer N increases the volume of soil explored by roots, or 'apparent', caused by pool substitution or by isotope  displacement reactions. Pool substitution is the process by which added labelled N stands proxy for native unlabelled N that would otherwise  have been removed from that pool. Microbial immobilization of N, whether driven by the decomposition of soil organic matter or by the decomposition  of plant roots, can lead to pool substitution and is the dominant cause of apparent ANIs. Denitrification and plant uptake of N can also, under special circumstances, lead to pool substitution and thus give rise to apparent ANIs. Isotope displacement reactions, in which the added labelled N displaces native unlabelled N from a 'boundï pool, can lead to apparent ANIs but are only likely to be of significance in exceptional circunstances. The relationship between ANIs, 'A' values and N fertilizer uptake efficiencies are examined by means of a simplemodel for uptake of 15N-labelled fertilizer by a crop. A positive 'apparent' ANI is accompanied by an 'A' value that changes as fertilizer applications increase, Likewise, a positive 'apparent' ANI also causes fertilizer uptake efficiency to appear lower when measured by the uptake of 15N than when measured by the non-isotopic 'difference' method.	
Palavras-Chave: 	Fertilizer nitrogen; Interacao; Interactions; Nitrogenio do solo; Soil nitrogen.	
Thesagro: 	Fertilizante Nitrogenado.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Meio Norte / UEP-Parnaíba (CPAMN-UEPP)	
Exemplares: 	CPAMN-UEPP - (8098-1) - ADD - SP - -- - 98.00027 -  - 1998.00027 - DIS