尾叶桉幼林地上部分生物量及养分循环的研究

Above-Ground Biomass Production and Nutrient Cycling of Young Plantation of Eucalyptus urophylla

论述了２～３年生尾叶桉幼林地上部分生长、生物量积累和生物量在树木各器官及各径阶中的分配，林分净生产量，树木各器官及凋落物的养分含量和林分的养分循环。２年生时林分的生物量为２２．９ｔ／ｈｍ２，其中干材占６０．２％，皮占８．９％，枝占１４．７％，叶占１６．２％。３年生时林分生物量为４０ｔ／ｈｍ２，其中干材占６３．６％，皮占７．７％，枝占１４．１％，叶占１４．６％。年净生产量为２０．５ｔ／ｈｍ２，约５０％为树干生物量的增长，凋落物仅占１６．７％。２年生时林分Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ，Ｓｉ、Ｍｎ、Ｚｎ、Ｃｕ和Ｂ的积累量（ｋｇ／ｈｍ２）为１５７．６、５．４２、５９．３、２３．９７、９．２７、１４．１６、５．２６、０．４２７、０．１２５和０．５８８；３年生时为２４７．８、８．２、９１．１、４０．３、１７．５、２６．３、８．１２、０．７１１、０．２２１和０．９８１。２～３年生时，Ｎ、Ｐ和Ｋ的循环速率低于２０％；Ｃｕ、Ｚｎ和Ｂ的循环速率低于３０％。

In this paper,the above-ground growth,Biomass accumulation and distribu-tion among different diameter classes and tree components,primary net productivity,nutrientconcentration in 4 tree components and litter,nutrient cycling(not include leaching)of 2 to 3years old plantation of Eucalyptus urophylla were mentioned.The above-ground biomass ofthe plantation of 2 years old were 22.9 t/hm2 and 40.Ot/hm2 of 3 years old,of which therewere 60.2% stem-wood,8.9%stem-bark,14.7%branch and 16.2%leaves at 2 years,and63.6 stem-wood,7.7%stem-bark,14.1%branch and 14.6%leaves at 3 years. The primarynet productivity of the 2 to 3 years old plantation was 20.5t/hm2,of which more than 50%was stem biomass increment and 16.7%was litter. N,P,K,Ca,Mg,Si,Mn,Zn,Cu and B ac-cumulation was 157.6,5.42,59.3,23.97,9.27,14.16,5.26,0.427,0.125 and 0.588 kg/hm2at 2 years,and 247.8,8.2,91.1,40.3,17.5,26.3,8.12,0.711,0.22l and 0.981 kg/hm2 at 3years respectively.In the 2 to 3 years old plantation,N,P, K turn-over rates were lower than0.2 and Cu, Zn and B turn-over rates were lower than 0.3.