Studies On The Sustained Effectiveness Of Applying Cu And Zn On Chinese Fir Plantation

The contents of NPK and Cu,Zn in the soil decrease gradually due to unreasonable cultivation measures in the process of cultivating Chinese fir plantation,and brings out the plantation growth decrease.Many scholars show that fertilization can promote trees growth,the effectiveness of applying especially the microelement fertilizer is significant.This research was set up in Fujian Minhou Baisha state-owned tree farm,and selected 2-year-old,5-year-old and 12-year-old Chinese fir plantations for this experiment of applying NPK or NPK+Cu or NPK+Zn fertilizer,and emphatically analysed the growth variation of 3 different age at the 3rd and 9th year after fertilization.The results are as shown below.1.The effects of fertilization on the soil nutrients content(1)After comprehensively analysing the Changes of the soil nutrients content of 2 years later,the effect of applying NPK+Zn fertilizer to the 2-year-old Chinese fir was the best,the contents of the available N,P,K and available Cu,Zn nutrients in surface layer 0-20cm increased by 30.24%,41.67%,25.4%,48.72%,98.63%over before experiment.The effect of applying NPK+Cu fertilizer to the 5-year-old and 12-year-old Chinese fir was the best,the each nutrient content of the former increased by 12.24%,89.26%,-25.24%,43.48%,14.21%,and that of the latter increased by 14.36%,-4.81%,-16.62%,1.72%,23.12%.The effectiveness of applying fertilization on total nutrient of 3 different age Chinese fir was similar to that of the available nutrient.2.The effects of fertilization on the growth of 3 different age Chinese firThe increments of 3 different age Chinese fir at the 3rd and 9th year after fertilitzation were all greater than that of non fertilization,After analyzing the changes of 3-year increments and 9-year increments,the results proved that the increment growth with applying fertilization has continued to gain.The effect of applying NPK+Zn fertilizer to the 2-year-old Chinese fir was the best,and the 9-year increments of DBH,tree height,stand volume and biosmass were 15.21 cm,11.21 m,12.743 m3,5935.8 kg respectively,that increased by 13.8%,9.0%,36.1%,33.5%over the control plot.The second place was of applying NPK+Cu fertilizer,that increased by 10.3%,6.2%,24.1%,22.6%over the control plot.The effect of applying NPK+Cu fertilizer to the 5-year-old Chinese fir was the best,and the 9-year increments of DBH,tree height,stand volume and biosmass were respectively 9.91 cm,7.02 m,13.731 m3,5929.7 kg,that increased by 27.5%,3.2%,35.4%,35.3%over the control plot.The effect of applying NPK+Zn fertilizer to the 12-year-old Chinese fir was the best,and the 9-year increments of DBH,tree height,stand volume and biosmass were respectively 5.35 cm,3.89 m,18.108 m3,7330.2 kg,that increased by 19.4%,9.3%,31.4%,30.9%over the control plot.The second place was of applying NPK+Cu fertilizer,that increased by 15.0%,9.6%,15.5%,14.9%over the control plot.3.The effects of fertilization on DBH and tree height varying coefficient of Chinese fir at different agesAfter 9 years with fertilitzation,the DBH and tree height varying coefficients of 2-year-old,5-year-old and 12-year-old Chinese fir plantations with applying NPK+Cu fertilizer were all the least,the DBH varying coefficients decreased by 13.3%,8.8%and 4.9%compared with no fertilization,the tree height varying coefficients decreased by 13.1%,0.0%and 9.8%.4.The effects of fertilization on the first branch height ratio of Chinese fir at different agesAfter 9 years with fertilitzation,the first branch height ratio of 2-year-old Chinese fir plantations increased from 12.1%to 20.5%compared with no fertilization,fertilization intensified the trees self-pruning intensity;The first branch height ratio of 5-year-old and 12-year-old Chinese fir plantations decreased from 14.1%to 16.4%and 0.1%to 5.8%,fertilization retarded the trees self-pruning intensity.5.The effects of fertilization on the Height Diameter ratio of Chinese fir at different agesAfter 9 years with fertilitzation,the Height Diameter ratio of Chinese fir at different ages with applying fertilizer were almost lower than that of non fertilization,that of of 2-year-old Chinese fir plantations with applying NPK+Zn fertilizer was the least,and decreased by 4.3%compared with no fertilization.The Height Diameter ratio of 5-year-old and 12-year-old Chinese fir plantations with applying NPK+Cu fertilizer was the least,respectively decreased by 9.2%and 3.9%.