00287nam a2200109Ia 4500008004100000082002000041100002100061245003000082260004200112300001000154650001300164140113s9999    xx            000 0 und d  a631(047.1 K8.20  a" Norman, A. G."  aAdvances in agronomy v.20  b"New York : Academic Press Inc, 1968"  a379p.  aAgronomy