川西南干热河谷赤按人工林生物量和营养元素含量

BIOMASS AND NUTRIENT ELEMENT CONTENT OF EUCALYPTUS PLANTATIONS OF DRY-HOT VALLEY IN SOUTHWEST SlCHUAN

用林木生物量回归方程，求得川西南干热河谷五年生赤桉纯林中乔木层生物量１３１３３．９ｋｇ／ｈａ（年平均生长量８０７９．７ｋｇ／ｈａ），草本层生物量５５２．０ｋｇ／ｈａ（枯落物现存量５９１．６ｋｇ／ｈａ）；赤桉与山毛豆混交林林分生物量２７１８６．９ｋｇ／ｈａ，其中赤桉生物量１６４９４．３ｋｇ／ｈａ（年平均生长量６６２０．２ｋｇ／ｈａ），灌木层生物量１０３６３．６ｋｇ／ｈａ，草本层生物量３２９．０ｋｇ／ｈａ（枯落物现存量１２６４．３ｋｇ／ｈａ）．混交林中赤桉生长好于纯林中赤桉的生长。林分营养元素含量不同植物差别很大，同种植物各器官也有所差别．各器官中营养元素含量顺序一般为：ｃａ＞Ｎ＞Ｍｇ＞Ｋ＞Ｐ，Ｐ是林地土壤缺乏的元素。

Riomase, productivity and nutrient elements of several fiveased Eucalgtws plantations(including pure plots and mixed with white tephrosia plots) in Jinshajang River valley have beenstudied. The biomass of trees is measured according to investigation on every tree and allometrymethedi biomass of shrub and graes are measured by harvesting, as wdll as the litter has beeninvestigated. A series of biomass regression equations of Eucalyptus camaldulensis and its different partsrefated with tree height H and diameter D have ben estublished,which refative coeffecients areabove 0. 90 mostly. Depending on the investigation data,they are valuable in reference. Theresult is that the biomass of tres in the pure plot is 13133. 9kg/ha, annual increment is3 079. 7kg/ha , biomass of grass is 552. 0kg/ha , and the amount of litter is 591. 6kg/ha ; the totalbiomass of mlxed plot is 27 1 86. 9kg/ha ,in which the biomass of tras ,shrubs , grass and litter are16 494. 3kg/ha , 10 363. 6kg/ha , 329. 0kg/ha ,and 1 264. 3kg/ha respectively.It can concluded that the mixed plots have better effect on the biomasa and productivity.Meanwhile,the nutrient element content of the plantis different organs has been determined. Itshows that the nutrient content is different among various species ,and that of various orsans inthe same plant have a littie differenee. The sequence of the nutrient element contents in the twokinds of plots from maximum to mininium is Ca>N>Mg>K>P. P(Phosphorus) is the limitedelement in such sites