Efficient level of phosphorus fertility in paddy soils International symposium on distribution, characteristics and utilization of problem soils

agricultural chemicals anthropogenic soil types application methods arroz cereales cereals crops cultivos cultivos de grano economic plants elements engrais environment environnement fertilizers fosforo grain crops medio ambiente methode methods no metales nonmetals paddy soils phosphore phosphorus plantas plante plante de culture plants produit agrochimique rice riz site factors soil types type de sol