TY  - BOOK
AU  - Sigunga, D.O.
TI  - Fertilizer nitrogen use effeciency and nutrient uptake by maize ( Zea mays L) in Vertisols in Kenya
AV  - THE S 667 .C8S54 
PY  - 1977///
CY  - Wageningen
PB  -  Agricultural University
KW  - Nitrogen, Fertilizers
ER  -