00313nam a2200097Ia 4500008004100000082002000041100002000061245006700081260005900148300000800207140113s9999    xx            000 0 und d  a631.8(026)   L0  a"De Geus, J.G."  aFertilizer guide for food grains in the tropics and subtropics  a1970b"Centre D'etude, Del'azote"cZurich(Switzerland)  a119