Studies on leaf and fruit analysis and fruitfulness of grapefruit (C.paradisi) in relation to the level of fertilization with NPK in the area of Crete

abonos nk analyse de tissus calidad engrais nk fertilisation fertilizer application feuille fruit crops fruit growing frutales fruticultura grapefruits grecia greece hojas leaves nitrogen potassium fertilizers pomelo quality tissue analysis toronja