[Mineral nitrogen availability in soils treated with hydrolized leather fertilizers]

abonos nitrogenados ammonia ammoniac ammoniaca analisi del terreno analyse de sol azote azoto clay soils concimi azotati cuero cuir cuoio disponibilidad de nutrientes fertilisation fertilizer application laboratory experimentation leather mineralisation mineralization mineralizzazione nitrate nitrates nitrati nitratos nitrogen nitrogen fertilizers nutrient availability sandy soils soil soil analysis soil chemicophysical properties sol sol argileux sol sableux sperimentazione in laboratorio suelo suelo arcilloso suelo arenoso suoli argillosi suolo terreni sabbiosi