Medium-term effects of poultry manure on pine N uptake in a 15N labelled burnt soil
The effects of poultry manure (PM), used for the reclamation of a 15N-labelled burnt soil, on N nutrition of pine seedlings were evaluated during a year in a pot experiment. Six treatments were used: 15N-labelled soil (LS), 15N-labelled burnt soil (BLS) and BLS+PM at doses equivalent to 1, 2, 4 and...
| Autores: | , , |
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| Formato: | artículo |
| Fecha de publicación: | 2008 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/57405 |
| Acesso em linha: | http://hdl.handle.net/10261/57405 |
| Access Level: | acceso abierto |
| Palavra-chave: | N availability Pinus pinaster Re-afforestation Wildfires |
| Resumo: | The effects of poultry manure (PM), used for the reclamation of a 15N-labelled burnt soil, on N nutrition of pine seedlings were evaluated during a year in a pot experiment. Six treatments were used: 15N-labelled soil (LS), 15N-labelled burnt soil (BLS) and BLS+PM at doses equivalent to 1, 2, 4 and 8 Mg ha-1 of dry PM (PM1, PM2, PM4 and PM8, respectively). Either in the whole tree or the different organs, N concentration: a) decreased (P # 0.05) in the order LS > BLS, BLS+PM1, BLS+PM2, BLS+PM4 > BLS+PM8; and b) was negatively correlated with phytomass production (P< 0.05 to P< 0.01). The two highest amounts of assimilated N (in kg-1 dry soil basis) were found in LS and BLS (130-134 mg) and the lowest in BLS+PM8 (87 mg), the other treatments being in an intermediate range (108-115 mg). Irrespectively of the soil treatment, 56-66% of the pine-N was accounted for by needles, 29-32% by roots and 8-12% by stems, the differences among organs being always significative (p< 0.05). The percentage of pine-N derived from PM (%PNDFM) increased steadily with PM dose, from 1.7% in BLS+PM1 to 13.3% in BLS+PM8, reaching values for the two highest PM doses within the range found for 15Nmineral fertilizers in forests. From 8.2 to 16.9% of the PM-N was assimilated by the pines; although differences among treatments were no significative, the two highest values were found in BLS+PM4 and BLS+PM8. Therefore, the 15N data showed clearly that: a) there is a positive medium-term effect of PM on pine N nutrition during the reafforestation phase of burnt forest reclamation; and b) the lower total N uptake by pine seedlings in the PM treatments was explained by their lower levels of soil available N due to its exportation with the phytomass of the preceding ryegrass culture, used for the early protection phase in the burnt soil reclamation procedure. |
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