A Study on the Cause of Low Yield and Measurements of Raising Productivity of Chinese Fir Seed Orchard in Qingyuan,Zhejiang Province

The yield of this seed orchard has been fluctuating in about 30 kg/ha for five years since 1984.It was found,through several investigations,that the main cause of low yield were: improper fertilization after fruiting that caused excessive growth of trees;unfavourable climate in pollination period;the damage by insects and diseases.The yield rapidly raised up to 84.15 kg/ha in 1989 and over 60kg in 1990,after the integrated measurements had been adopted,that were: changing the make up of fertilizers-increasing the content of P and K;artificial complement pollination;bonding with wire and cutting bark in half-ring like on trunk and controlling of insects and diseases.