Analysis of combining ability and heritability of nicotine content,total nitrogen content and nitrogen/nicotine ratio in burley tobacco;

Through analysis on chemistry properties of various nitrogen forms in compound fertilizers,some problems existing in determination of total nitrogen content in compound fertilizer are solved,and the qualitative analysis of nitrogen form and its key points is also presented for a reference in determination of compound fertilizer.

Known and unknown total nitrogen in water were measured by ionic chromatograph and GBl 1894-89 ultraviolet spectrophotometer.

66 kg were allocated into 3 groups to feed diets with PPM or soybean meal(SBM)as only protein source,and N-free diet to determine endogenous amino acid excretion to calculate amino acid true digestibility.