Effect of elemental sulphur on the development of root systems in Scots pine (Pinus sylvestris) and Norway spruce (Picea abies)

analyse de tissus azufre edaphic factors feuille hojas largura leaves length longueur measurement mesure peso picea abies pinus sylvestris plant condition plant response plant soil relations poids racine relaciones planta suelo relation plante sol respuesta de la planta root systems roots sistema radicular soufre sulphur tissue analysis weight