Measurement of Available B Content and the Effect on Application of B Fertilizer in Chinese Fir seed Orchard

The samples of soil and plant's needle,cone taken from Zhejiang's Chinese fir seed orchards were tested,And the results showed that the content of water-soluble B in soil is only 0.13～0.24 ppm,which is obviously lower than the critical concentration of 0.5 ppm.The B contents of plant needle and cone are only8.9～22.7 ppm and 4.1～16.1 ppm respectively,which is also lower than the normal one. Applying appropriate amount of B to Chinese fir seed orchard, the cone yields of single tree and per hectare stand are averaged 35.08%,48.42% higher than those of the control respectively,the seed output rate is 9.40%,the germination percentage is 14.99% and the 1000-seed-weight is 6.54%,which is higher than that of the control. The best time for fertilization is likely to be before middle August and middle June. The proper amount of fertilizer used is 60 g borax generally. The study also revealed that the better yield could be achieved to apply B mixed with N,P,K fertilizers instead of Bor N,P, K mixed fertilizer seperately. The amount of cone of single tree and per hectare stand can be increased by 22.55% and 15.71% more with the compound fertilizer,and the seed quality could also be improved remarkably.