00297nam a2200109Ia 4500008004100000082002200041100002200063245006700085260000900152300001000161650001600171140113s9999    xx            000 0 und d  a631.8:633(213) L0  a" De Geus, J. G."  aFertilizer guide for food grains in the tropics and subtropics  b1970  a119p.  aFertilizers