Effects of bag controlled fertilization on growth and ecological stoichiometry of Cunninghamia lanceolataolata plantation

In order to improve the stock volume of Cunninghamia lanceolata plantation，the growth and stoichiometric characteristics of C. lanceolata were studied under different fertilization methods. The results showed that: after three years of fertilization，the average annual growth of tree height was 1.70-2.07 m. Among them， compared with the blank control（ CK），there was the largest annual growth in treatment A（ 6 holes，fertilizer depth of 15 cm），and after four years of fertilization，the average annual growth of tree height increased by 1.32-1.55 m. The annual growth rate of all fertilizer treatments was higher than that of CK，and the maximum increase was 17.1% in the treatment C（ 10 holes，fertilizer depth of 15 cm）. Bag controlled fertilization could effectively improve the stock volume of C. lanceolata plantation，treatment C had the best effect. The release rate of bag controlled fertilization with 6 holes and fertilizer depth of 25 cm may be more suitable for plant growth requirements. The application of bag controlled fertilizer could increase the concentration of soil C，N and P in the soil of C. lanceolata plantation， compared with CK. Bag fertilization can release nutrients effectively and consistently to ensure the growth of C. lanceolata，and the biggest stock volume growth was in treatment C.