广西不同林龄和区域马尾松人工林的土壤C、N、P化学计量特征

Stoichiometric Characteristics of Soil C, N and P in Pinus massoniana Plantations of Different Ages and Regions in Guangxi

关键词:  马尾松人工林  土壤化学计量特征  不同林龄  区域  相关性

Key words:  Pinus massoniana plantation  soil stoichiometric characteristics  different stand age  region  relevance

摘要:

为探明广西马尾松Pinus massoniana人工林土壤碳(C)、氮(N)、磷(P)化学计量特征，揭示马尾松人工林土壤养分平衡机理及其时空动态变化，为马尾松人工林可持续经营提供理论依据，研究以广西4个典型区域马尾松人工林为对象，采用空间代替时间的方法，比较不同区域各林龄土壤有机碳(SOC)、全氮(TN)和全磷(TP)含量及其化学计量比的变化规律。结果表明：SOC、TN和C/N的变异系数较小，分别为21%、27%和22%，属弱变异，在不同林龄和区域中其值比较稳定。林龄、区域及其交互作用对SOC、TN、TP、C/P、N/P的变化均有显著影响(P<0.05)。SOC、TN含量呈波动性变化，在成熟林阶段最低；SOC含量在幼龄林阶段最高，TN含量在近熟林阶段最高。土壤TP含量在中龄林阶段最低，且随林龄增加呈先减少后增加的趋势。土壤C/N、C/P、N/P平均值均在成熟林中最高，且显著高于近熟林和过熟林(P<0.05)；土壤C/P、N/P平均值随林龄增加呈先减少后增加再减少的趋势。华山地区SOC、TN和TP含量最低，而土壤C/N、C/P、N/P平均值最高。天洪岭地区土壤C/N平均值最低，镇龙地区土壤C/P、N/P平均值最低。相关性分析表明，土壤C/N与TN含量显著负相关；土壤C/P与TN、TP含量均呈显著负相关关系；土壤N/P与SOC、TP含量均呈显著负相关关系，与C/P显著正相关。总体来说，广西马尾松人工林主要受到P限制，且在速生阶段比较明显。为保证马尾松人工林发育，在马尾松速生阶段可适当施加P肥。

Abstract:

To investigate the stoichiometric characteristics of soil carbon (C), nitrogen (N) and phosphorus (P) in Pinus massoniana plantations in Guangxi, to reveal the mechanism of soil nutrient balance in P.massoniana plantations and its spatial and temporal dynamics of P.massoniana plantations, and to provide a theoretical basis for sustainable management of P.massoniana plantations, and the change rule of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) contents and stoichiometric ratios at different forest ages in different regions were compared by using the method of space instead of time.The results showed that the coefficients of variation for SOC, TN and C/N were small, which was 21%, 27% and 22%, respectively, belonging to weak variation, and their values were relatively stable in different forest ages and regions.Forest age, region and their interaction all had significant effects on the variation of SOC, TN, TP, C/P and N/P (P<0.05).The contents of SOC and TN in soil fluctuated, which were the lowest in mature forest stage.SOC contents were highest in the young forest stage and TN contents were the highest in the near mature forest stage.TP contents in soil were the lowest in the middle-aged forest stage, and with the increase of forest age, it showed a trend of first decreasing and then increasing.The average values of soil C/N, C/P and N/P were all the highest in mature forests, and were significantly higher than those in near-mature and over-mature forests (P<0.05).With the increase of forest age, the average values of soil C/P and N/P showed a trend of first decreasing, then increasing and then decreasing.SOC, TN and TP contents in soil were the lowest in Huashan area, while the average values of soil C/N, C/P and N/P were the highest.The average values of C/N in soil in Tianhongling area was the lowest, and the average values of C/P and N/P in soil in Zhenlong area were the lowest.Correlation analysis showed that C/N in soil was significantly negatively correlated with TN content, and C/P in soil was significantly negatively correlated with TN and TP content.N/P in soil was significantly negatively correlated with SOC and TP content, and significantly positively correlated with C/P.In general, Guangxi P.massoniana plantations are mainly restricted by P, and it is more obvious in the fast-growing stage.In order to ensure the development of P.massoniana plantations, P fertilizer can be appropriately applied in the fast-growing stage of P.massoniana.