Determination of the Nitrogen Fractions in Atlas and Milo Sorghum Plants.

During, the course of experiments conducted to find an explanation for the varying susceptibility of sorghum varieties to chinch bug injuries, considerable eviden'ce has been collected indicating that nitrogen may be one of the factors involved in the problem. It is a known fact that, in general, additions of nitrogen fertilizers to planits increase the susceptibility of such plants to insect injury (3); DAHMS has conifirmiied this fact for sorghums (1). Our work on the chemical composition of various varieties has shown that suseeptible varieties generally have a higher nitrogen content than non-susceptible varieties grown under similar conditions. Particularly is this true of field-grown Atlas and Dwarf Yellow Milo plants, which are representative, respectively, of highly resistant and extremely susceptible varieties. The study was undertaken to determiiine whether certain nitrogen fractions were present in greater abundanee in one variety than in the other, such information being desired for cultural solution studies dealing with insect susceptibility of plants, and in the preparation of solutions for culturin(g chinieh bugs.