Agricultural nitrogen, phosphorus and potassium balances in Germany - Methodology and trends 1970 to 1995

agricultura agricultural sector agriculture alemania allemagne analyse input output azote cycling farm management farm planning fertilidad del suelo fertilisation fertilizer application forecasting fosforo germany gestion de l'exploitation agricole input output analysis manejo de fincas methode methods nitrogen phosphore phosphorus planification de l'exploitation potasio potassium secteur agricole sector agrario soil fertility tendance tendencias trends