退化红壤植被恢复团聚体及化学计量特征

为了探究不同植被恢复模式对土壤碳(C)、氮(N)、磷(P)分配格局及其生态化学计量特征的影响,为红壤侵蚀区的植被恢复措施及生态治理模式优化提供科学依据,以江西省泰和县红壤严重退化地为研究对象,对研究区马尾松纯林、湿地松纯林、木荷纯林、马尾松木荷混交林(马木混交林)以及湿地松木荷混交林(湿木混交林)5种植被恢复模式0—20,20—40cm土层不同粒径水稳性团聚体C、N、P分配格局及其化学计量特征进行了研究。结果表明:(1)0—40cm不同粒径团聚体分别占总重56.34%(>2mm),30.01%(0.25~2mm),7.14%(0.053~0.25mm),6.54%(<0.053mm),各植被恢复模式土壤水稳性团聚体含量随着粒径的减小而降低,且差异显著(p<0.05),马木混交林>2mm土壤水稳性团聚体含量显著高于其他恢复模式(p<0.05);(2)各植被恢复模式土壤C、N、P含量以马木混交林及湿地松纯林较高,水稳性团聚体C、N、P的含量总体随着粒径减小呈升高的趋势,以较小粒级养分含量较高,且存在显著差异(p<0.05);土层间C、N含量差异显著,P无显著差异,C∶N、C∶P及N∶P存在显著差异(p<0.05);粒径间C∶N、C∶P及N∶P存在显著差异;土壤团聚体C、N与C∶N、C∶P、N∶P均呈极显著相关关系,N∶P值较高且P与N∶P存在显著负相关性(p<0.05);(3)土壤C、N与土壤团聚体C、N含量显著相关(p<0.05),土壤团聚体C、N与土壤容重及含水率存在极显著相关性(p<0.01)。研究结果表明,不同植被恢复模式对土壤养分的改善作用主要集中于表层土壤;土壤团聚体养分对土壤养分状况具有指示作用,且土壤团聚体养分保持能力与土壤物理性质有关;研究区植被生长限制因素以P限制为主且大团聚体和微团聚体受P限制作用更严重;马木混交林较其它植被恢复模式对土壤质量和结构提升均具有显著作用。

Distribution and Stoichiometry of Water-stable Aggregates of Different Vegetation Restoration Patterns in Degraded Red Soil Regions

In order to explore the effects of different vegetation restoration models on carbon (C) nitrogen (N) phosphorus (P) content of soil and its ecological stoichiometry and provides a scientific basis for vegetation restoration measures and ecological management model optimization in red soil erosion areas. The severely degraded red soil in Tai he County of Jiangxi Province was taken as the research object, and we chose the water stable aggregate which in 0-20, 20-40 cm soil layer with five restoration patterns (Pinus massoniana Lamb. pure forest, Pinus elliottii pure forest, Schima superba Gardn. et Champ. pure forest, and mixed forest of Pinus massoniana Lamb. and Pinus elliottii) to explore it. The results show that:(1) The average content of water-stable aggregates of 0-40 cm was 56.34% (>2 mm), 30.01% (0.25~2 mm), 7.14% (0.053~0.25 mm), 6.54% (<0.053 mm), respectively. The content of soil water-stable aggregates decreased with the reduction of soil particle size, and the difference was significant (P<0.05). In mixed forest of Pinus massoniana Lamb.,>2 mm water-stable aggregates content was significantly higher than that in other recovery models (P<0.05); (2) The contents of C, N and P in the vegetation restoration model were higher in the mixed forest of Pinus massoniana Lamb. and pure forest of Pinus elliottii. The content of C, N and P in soil water-stable aggregates increased in totality with the decrease of particle size and the content of nutrients with smaller grain size was significantly higher (P<0.05); There are significant differences in the content of C, N and C:N, C:P, N:P in different soil layers, but no distinct difference in the content of P. There were significant differences of C:N, C:P and N:P among particle sizes. Soil aggregates C, N are significantly correlated with C:N, C:P, N:P, N:P value is high and there is a significant negative correlation with P (P<0.05); (3)Soil aggregates C and N were significantly correlated with soil C and N (P<0.05), soil bulk density and water content (P<0.01). Research indicates:The improvement of soil nutrients by different vegetation restoration models is mainly concentrated in the topsoil. Soil aggregates had an indicating effect on soil nutrient, which related with soil physical properties. The limiting factors of vegetation growth in the study area are mainly P-limited and the macroaggregates and microaggregates are more severely restricted by P, mixed forest of Pinus massoniana Lamb. have significant effects on soil quality and structural improvement compared to other vegetation restoration models.