Five Years′ Growth Response of Young Slash Pine to Fertilization

The fertilization trial of young slash pine(Pinus elliottii)was established on the quarternary period red earth with low organic matter content in Yongfeng County of Jiangxi Province to examine the growth responses of N、P、K application and the effects at different dressing period.The growth responses during the first five years after fertilizing showed that the maximum stocking was 42.01 m3/hm2 from the NP treatment,as dressing N 100,P2O5 100 kg/hm2,resulting in 90% volume increase.Alone phosphours fertilizing,as dressing P2O5 50,100,200 kg/hm2 at planting,resulted in 34%～74% volume increase. No significant differences of growth response occurred in various fertilizing levels of alone P treatments.However,fertilizing P at planting gave more growth response than dressing after planting.Though obvious negative response in N alone application during the first three years after dressing,the negative response disappeared by the end of the fifth year.No significant response occurred in K application.