Abstract:Triploid Populus tomentos, widely planted in the north of Yellow River, is an ideal tree species for the pulpwood and plywood with the characteristics of short rotation, fast growth, excellent quality and anti-disease.Fertilization experiments with an orthogonal experimental design (L1645) were conducted in Wei County, Xingtai City, Hebei Province. The nutrients dynamics in the leaves of Triploid Populus tomentosa were studied with the application of Diagnosis and Recommendation Integrated System (DRIS) method. Based on N, P and K concentrations in the leaves of Triploid Populus tomentosa from July to October in the 3rd year after plantation, nutrition diagnosis standards of DRIS graphic and index methods were successfully established with high accuracy. The optimal N/P, N/K and K/P ratios were 19.116±1.270, 3.054±0.289 and 6.356±0.651, respectively. Diagnostic accuracy reached 80% with the analytical data in September for return test. The nutrients requirement by Triploid Populus tomentosa was in the order of N>K>P, which was in accord with the actual application rate of fertilizers. The optimal nutrients ratios can provide scientific basis for rational fertilization and spreading of Triploid Populus tomentosa.