[Nutrition diagnosis and fertilization of forest in the Qinling Mountains, China].

We examined the contents of total nitrogen (TN) and total phosphorus (TP) in needle, litter, and soil of forest on the southern slope of the Qinling Mountains in Shaanxi, China. We conducted nutrition diagnosis of forest, analyzed nutrient limitation pattern, the fertilization types and amount to increase growth, to provide support for precision fertilization and scientific cultivation of big timber of . The results showed that the proportion of big timber (DBH>26 cm) and individuals with the potential to grow into big timber (18 cm