Utilize este identificador para referenciar este registo: http://hdl.handle.net/10348/8706
Título: Potassium supplying capacity of northeastern Portuguese soils
Autor: Portela, Ester
Palavras-chave: illite
K release
K reserve
K uptake
mica
non-exchangeable K
potassium
ryegrass
Data: 1993
Resumo: In Portugal, the response to K application is often inconsistent with the Egner-Riehm values for available K. This is partly related to high K reserves of some soils. Twenty surface soils representative of different parent materials from NE Portugal were studied to determine their K supplying capacity. Continuous cropping with perennial ryegrass permitted the assessment of the relative ability of soils to release non-exchangeable K. Soils were classified in the range of available K from medium to very high. However, their ability to supply K in the short and long term are very different. In some soils K status measured by plant growth does not fall appreciably, whilst others are rapidly exhausted, and 30% of them are very deficient in K. The supplying capacity varied both with the nature of the parent material and the degree of weathering. The soils deficient in K are those derived from basic rocks and those with more weathered clay minerals. This is the case of the soils with the largest content of organic matter where the dominant clay minerals were kaolinite and vermiculite. Soils that have the highest capacity for supplying K are highly micaceous, like those developed from mica schists, phyllites or river alluvium. In fact the amount of K released from non-exchangeable form is well correlated with the amount of illite in the clay fraction. Soil types and K buffer power coupled with available K must be taken into account when planning any application of K.
URI: http://hdl.handle.net/10348/8706
Tipo de Documento: Artigo
Aparece nas colecções:DEBA - Artigo publicado em Revista Científica Indexada

Ficheiros deste registo:
Ficheiro Descrição TamanhoFormato 
PortelaK1993.pdf497,56 kBAdobe PDFThumbnail
Ver/Abrir


FacebookTwitterDeliciousLinkedInDiggGoogle BookmarksMySpace
Formato BibTex mendeley Endnote Logotipo do DeGóis Logotipo do Orcid 

Todos os registos no repositório estão protegidos por leis de copyright, com todos os direitos reservados.