火炬松人工林养分体内转移与内循环研究

摘要

A study on the internal nutrients transfer and cycling of the above|ground parts in the 15|years|old loblolly pine (Pinus teada L.)plantation,located in Xiashu forest farm,Jiangsu Province,was carried out.The results obtained were as followed:(1)The internal transfer of nutrients (N,P,K and Mg)in needle was more than in branch or in bole,which played the most important role in the internal transfer of nutrients in the above|ground parts,and the transfer ratios of N,P,K and Mg in the above|ground parts were 44.9?%,34.5?%,20.8?% and 30.7?%,respectively.(2)The nutrient return of N,P,K Ca and Mg were 55.78,6.13,26.70,70.79 and 20.30 kg*hm-2*a-1,which were 36.67?%,44.65?%,55.30?%,78.02?% and 42.84?% of the nutrients requirement,separately,and the soil depletion of N,P,K,Ca and Mg were 22.48,2.13,4.64,26.98 and 11.64kg*hm-2*a-1,which were 23.99?%,22.76?%,11.84?%,24.32?% and 33.10?% of the nutrients uptake,respectively.(3)The nutrients availability in this plantation was higher than that in Chinese fir plantation and Oak forest in this region,but the loblolly pine plantation is still in the stage of nutrients depletion.%对江苏省下蜀林场火炬松人工林(15年生)地上部分养分体内转移和内循环特点进行了初步研究，结果表明：(1)在体内养分转移中，叶的贡献最大，N、P、K和Mg元素的平均转移量均大于枝和干；地上部分养分N、P、K和Mg元素的转移率分别为44.9?%，34.5?%，20.8?%和30.7?%。(2)地上部分养分归还量N、P、K、Ca和Mg元素分别55.787，6.13，26.70，70.79和20.30kg*hm-2*a-1分别占需要量的36.67?%，44.65?%55.3?%，78.02?%和42.84?%；地上实际消耗土壤中的养分量N、P、K、Ca和Mg分别为22.48，2.13，4.64，26.98和7.41kg*hm-2*a-1，分别占吸收量的23.99?%，22.76?%，11.84?%，24.32?%和21.09?%。(3)与当地的杉木林和次生栎林相比，该火炬松人工林养分利用率高，并处于养分消耗阶段。