福寿林场4种典型林分的土壤肥力分析及综合评价

Soil Fertility Analysis and Comprehensive Evaluation of Four Typical Forest Stands in Fushou Forest Farm

以湖南省平江县福寿林场杉木纯林、杉木混交林、栎类次生林和竹林为研究对象,选取土壤有机质、碱解氮、全氮、全磷、速效钾、速效磷、土壤容重和pH值8个评价指标对4种不同林分的土壤肥力进行综合对比分析,并基于乘除法计算原理,构建林分土壤肥力综合评价指数,确定其土壤肥力评价等级。结果显示:(1)在0~60 cm土层中,栎类次生林土壤有机质、碱解氮、速效磷、全磷、全氮含量均为最大,竹林土壤pH值和容重均为最大,杉木纯林速效钾含量显著高于其它3种林分。(2)从土壤剖面垂直变化特征来看,4种林分有机质、碱解氮与全氮含量,均表现为随土层的增加而逐渐下降,其中栎类次生林各土层有机质含量均显著高于其它3个林分(P<0.05);4种林分土壤pH值随土层的加深无明显变化规律;杉木纯林、栎类次生林和竹林的土壤全磷及速效磷含量,均表现为随土层的增加而逐渐下降;4种林分土壤容重呈现出随土层加深逐渐增大的变化。(3)从土壤肥力的综合评价来看,4种林分土壤肥力状况排序为栎类次生林(0.39~0.58)>杉木混交林(0.22~0.29)>杉木纯林(0.20~0.30)>竹林(0.02~0.14)。与目前传统的土壤肥力综合评价方法相比,本文采用的土壤肥力综合评价指数法不需要计算各指标权重,且计算量小,可根据不同的土壤系统对模型参数个体数量适当进行增减,适用性强。

Taking the soil of Cunninghamia lanceolate forest,Cunninghamia lanceolate mixed forest,oak natural secondary forest,bamboo forest in Fushou Forest Farm of Pingjiang County,Hunan Province as the research objects,the soil fertility of these four kinds of forests were compared and analyzed.By selecting 8 indexes of soil organic matter,pH value,total nitrogen,total phosphorus,available phosphorus,available potassium,available nitrogen and soil bulk density,the comprehensive evaluation index of soil fertility of stand was constructed to determine the evaluation level of soil fertility based on the principle of multiplication and division method.The results showed that:(1)in 0-60 cm soil layer,the contents of soil organic matter,available nitrogen,available phosphorus,total phosphorus,total nitrogen in oak natural secondary forest were the highest,the soil pH and bulk density of the bamboo forest were the highest,and the content of available potassium in Cunninghamia lanceolate forest was significantly higher than that in other three stands.(2)From the vertical change of soil profile,the contents of organic matter,available nitrogen and total nitrogen in four kinds of stand decreased gradually with the increase of soil layer,and the content of organic matter in each soil layer of oak natural secondary forest was significantly higher than that of the other three stands(P<0.05);there was no significant difference with the deepening of soil layerin pH value of four stands;the contents of soil total phosphorus and soil available phosphorus in C.lanceolate forest,oak secondary forest and bamboo forest decreased with the increase of soil depth;the soil bulk density of the four stands increased gradually with the increase of soil depth.(3)From the comprehensive evaluation of soil fertility,the order of soil quality comprehensive index of the four forests was oak natural secondary forest(0.39-0.57)>Cunninghamia lanceolate mixed forest(0.22-0.29)>Cunninghamia lanceolate forest(0.20-0.30)>bamboo forest(0.02-0.14).Compared with the traditional comprehensive evaluation index of soil fertility,the comprehensive evaluation index method of soil fertility used in this paper does not need to calculate the index weight,and the amount of calculation is small.The model parameters can be appropriately increased or decreased according to different soil systems,which has strong applicability.