摘要
为探究尾巨桉乔木层养分随林龄变化的趋势,对闽南山区连续年龄序列(2年、3年、4年、5年、6年)尾巨桉(Eucalyptus urophylly×E.grandis)人工林乔木层的养分积累、分配和循环特征进行了研究.结果表明:(1)尾巨桉各组分中氮(N)的含量最高,其次是钾(K)、钙(Ca)、镁(Mg),最低的为磷(P).(2)尾巨桉养分贮量随林龄增长而增加,各林龄5种养分元素的总贮量依次为753.26、882.07、1 010.22、1 087.51、1 704.79 kg hm-2,其中树干的养分贮量最大,枝的贮量最小.(3)各年龄段人工林对5种养分元素的年净积累量分别为383.37、392.25、424.21、400.89、505.36 kghm-2a-1.(4)各林分养分年吸收量随林龄增加而增加,而养分归还量则呈相反趋势.(5)林分对营养元素的利用系数分别为0.51、0.44、0.42、0.37、0.30,随林龄增加而逐渐减小;循环系数分别为0.18、0.19、0.24、0.24、0.16;周转时间分别为8.76、9.75、7.58、9.39、17.47年.因此,尾巨桉在生长初期对养分的利用效率较小,中期归还给林地的养分多,到了后期对养分利用增加的同时,归还速率也变小,容易引起林地养分的匮乏,在尾巨桉生长初期和后期中应通过施肥、增加林下植被种类和数量来维持林地地力.
The nutrient accumulation and cycling were investigated from 2- to 6-year-old Eucalyptus urophylly x E. grandis plantations in the southern mountain region of Fujian Province, China. The results showed that N content was the highest in the tree components, followed by K, Ca, Mg and P. N content in the 2-, 3-, 4-year-old stands decreased, then increased slightly in the 5- and 6-year-old stands. The nutrient accumulations were 753.26, 882.07, 1 010.22, 1 087.51, 1 704.79 kg hm2 in the 2-, 3-, 4-, 5-and 6-year-old stands, respectively. Annual net nutrient accumulation was highest （505.36 kg hm-2） in the 6-year- old stand, and in the 2-, 3-, 4-, and 5-year-old stands, the values were 383.37, 392.25, 424.21,400.89 kg hm1 al, respectively. The nutrient absorption increased along stand age while nutrient return showed a decreased trend. The coefficients of nutrient utilization were 0.51, 0.44, 0.42, 0.37, 0.30 along the forest age. The nutrient cycling coefficients did not show obvious trend with the values from 0.16 to 0.24. The recycling period of nutrients was 8.76, 9.75, 7.58, 9.39, 17.47 years along with stand age, respectively. The results indicate that Eucalyptus urophylly x E. grandis plantations have low nutrient utilization efficiency in the early stage while have high nutrient utilization efficiency. Nutrient deficient would limit biomass accumulation in these plantations and fertilization management should be considered.
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2012年第6期897-903,共7页
Chinese Journal of Applied and Environmental Biology
基金
国家自然科学基金项目(No.31160153)
福建省林业厅科技项目(闽林科[2007]6号)
江西省教育厅科学技术研究项目(赣教技字[08535]号)
南昌工程学院青年基金(No.2006KJ006)资助~~
关键词
尾巨桉人工林
年龄序列
养分循环
Eucalyptus urophylly x E. grandis plantation
age sequence
nutrient cycle
