The long-term fertilizer trials at Moeystad, S.E. Norway

azote crop yield crops cultivos estructura del suelo farmyard manure fertilisation fertilizer application field experimentation fosforo fumier inorganic fertilizers moraine soils nitrogen noruega norway phosphore phosphorus plante de culture potasio potassium rendement des cultures rendimiento de cultivos soil structure sol de moraine structure du sol suelo de morrena