Accumulations and Annual Net Accumulations of Microelements in Cunninghamia lanceolata Plantations at Different Stand Ages in Northwestern Guangxi
In order to study chang chacteristics of accumulations and annual net accumulations of microele-ments in Cunninghamia lanceolata plantations in northwestern Guangxi,and to provide scientific basis for man-agement of high yield C.lanceolata plantations,taking 5-year-old,10-year-old,15-year-old and 20-year-old C.lanceolata plantations in Shankou Forest Farm of Nandan county in Guangxi as research objects,con-tents,accumulations,annual net accumulations and distribution characteristics of five microelements(Fe,Mn,Zn,Cu and B)in C.lanceolata plantations at different stand ages were analyzed and compared.Results showed that Mn or Fe content was the highest among five microelements,followed by Zn contents,and Cu or B content was the lowest in arbor layers of C.lanceolata plantations at different stand ages.Total accumulations of micro-elements in 5-year-old,10-year-old,15-year-old and 20-year-old C.lanceolata plantations were 6.868,13.445,17.662 and 22.087 kg/hm2 respectively,of which arbor layers accounted for 71.03%,85.46%,79.29%and 72.34%respectively,undergrowth vegetations accounted for 15.35%,5.48%,4.97%and 5.65%respective-ly,and litter layers accounted for 13.63%,9.06%,15.75%and 22.01%respectively.Increments of accumula-tions of microelements in arbor layers were 5-year-old to 10-year-old(6.612 kg/hm2)>10-year-old to 15-year-old(2.514 kg/hm2)>15-year-old to 20-year-old(1.973 kg/hm2).Total annual net accumulations of microele-ments in four stands at different stand ages were 0.976,1.149,0.975 and 0.811 kg·hm-2·a-1 respectively.Total annual net accumulations of Mn were the highest,followed by Fe and Zn,and total annual net accumulations of Cu or B were the lowest.When C.lanceolata plantations were 5-year-old to 10-year-old,B,Cu and Zn fertiliz-ers could be applied to promote growth of C.lanceolata.When C.lanceolata plantations were 10-year-old to 20-year-old,no fertilizer should be applied.
stand agemicroelementaccumulationannual net accumulationnorthwestern GuangxiCunning-hamia lanceolata plantation
万方数据
维普
