Studies on the nutritional diagnosis in fruit trees, 4: Boron content of leaf and soil of Unshu and Tankan [Citrus unshiu; Citrus tankan [tangor] orchards in Okinawa island [Japan]]

agrume agrume hybride anatomia anatomie anatomy asia asie bore boro boron citrus crosses citrus fruits crops cultivos cultural soil types economic plants elements environment environnement fruit crops frutales japan japon medio ambiente orchard soils plant anatomy plantas plante plante de culture plants satsuma satsumas semimetales semimetals site factors soil types sol de verger suelo de huertos tangerina tangerine tangerines type de sol type de sol de culture