Hello to all, Another article that may be of interest is titled " Soil fertility and the organic composition of plants, lysine, arginine and aspartic acid variations. The authors are L. W. Reed, V.L. Sheldon and W. A. Albrecht. The journal is Agronomy Journal Vol 52 Number 9 September 1960 pg 523-526 25 references cited... Joel Gruver U of MD, Agronomy