Abstract: The indices of nutrient diagnosis of N, P, K elements in leaves of walnut tree grown in Qi county, Shan Xi Province were studied from 1985—1990. The results indicate that actording to the nutrient element contents of leaves, the nutrient indices are as follows: For nitrogen, optimum content is 3.82—4.76%, latent deficient content 3.06—3.76%, severe deficient content<3.06%, for potassium they are 2.59—2.61%, 1.94—2.49%,<1.94% respectively, for phosphorous optimum content 0.21—0.24%, deficient content<0.19%, luxurious content>0.24%. Therefore, the annual optimum requirements for N, P, K each tree growning in this experimental site are 0.75kg, 2.5kg and 0.25kg respectively.

Key words: Walnut, N, P, K elements, Nutrient indices