00397nam a2200109Ia 450000500170000000800410001705000210005810000180007924501170009726000470021465000260026120251229183910.0251229s9999    xx            000 0 und d  aTHE S 667 .C8S54  aSigunga, D.O. 0aFertilizer nitrogen use effeciency and nutrient uptake by maize ( Zea mays L) in Vertisols in KenyacD.O Sigunga  aWageningenb Agricultural Universityc1977  aNitrogen, Fertilizers