00309nam a2200109Ia 4500008004100000082002000041100002100061245003100082260003600113650002000149650003000169220204s9999    xx            000 0 und d  a631/635bADV.70  aSparks, Donald L 0aAdvances in agronomy. V.70  aSan DiegobAcademic Pressc2001  aOrganic farming  aSoil carbon sequestration