柑橘／大球盖菇间作对三峡库区紫色土活性有机碳库的影响

摘要

分析柑橘园间作大球盖菇模式对紫色土活性有机碳库的影响，以期为土壤碳循环及缓解气候变化的研究提供基础数据和理论依据。通过在紫色土柑橘园中间作大球盖菇，对比分析密植间作（HD）、正常间作（TC）、稀疏间作（SP）和裸地对照（BT）及辅料对照（ST）等5组处理对紫色土柑橘园上下层（0～10 cm，30～50 cm）土壤中总有机碳（TOC）、可溶性有机碳（DOC）、易氧化有机碳（ROC）、轻组有机碳（LFOC）及土壤微生物量碳（SMBC）等指标的影响。在大球盖菇整个生长期中，柑橘／大球盖菇间作密度显著影响上、下层土壤中活性有机碳（DOC、ROC、LFOC、SMBC）的含量，且上层（0～10 cm）土壤中总有机碳和活性有机碳的含量显著高于下层（30～50 cm）土壤。此外，各处理在不同土壤层次中对不同活性有机碳组分的影响存在显著性差异，其中在上层（0～10 cm）土壤中，密植间作（HD）处理中活性有机碳（DOC、ROC、LFOC 及 SMBC）含量显著高于其他处理（P ＜0．05），而在下层（30～50 cm）土壤中，稀疏间作（SP）处理中可溶性有机碳（DOC）、轻组有机碳（LFOC）及微生物量碳（SMBC）的含量均高于其他处理（P ＜0．05）。柑橘／大球盖菇间作系统中，间作密度与总有机碳（TOC）、易氧化有机碳（ROC）存在显著负相关关系，与可溶性有机碳（DOC）、轻组有机碳（LFOC）和土壤微生物量碳（SMBC）存在极显著负相关关系，且不同活性有机碳组分间存在显著或极显著正相关关系。柑橘／大球盖菇间作能够显著提高上层（0～10 cm）土壤中碳库管理指数，却不利于下层（30～50 cm）土壤碳的累积。柑橘／大球盖菇间作在一定程度上能够提高紫色土土壤中活性有机碳的形成和累积，增加紫色土土壤碳储量。%In order to provide basic data and a theoretical basis for soil carbon cycle and climate change mitiga-tion research,the effect of Citrus tree/Stropharia mushrooms intercropping on “purple soil”labile organic car-bon was analyzed.Five tillage practices:high density intercropping (HD),traditional cultivation (TC),sparse intercropping (SP),bare ground tillage (BT)and straw mulching tillage (ST)were examined to analyze the soil total organic carbon (TOC),dissolved organic carbon (DOC),rapidly oxidized organic carbon (ROC), light fraction organic carbon (LFOC)and soil microbial biomass carbon (SMBC)in citrus groves.During the growing season of Stropharia mushrooms,the density of Citrus tree/Stropharia mushrooms intercropping sig-nificantly affected the labile carbon (including DOC,ROC,LFOC,SMBC).As expected,the content of total organic carbon and labile carbon in the upper layer (0-10 cm soil depth)was significantly higher than in the lower layer (30-50 cm soil depth).The content of labile carbon (including DOC,ROC,LFOC,SMBC)in the upper soil layer under high density intercropping (HD)practice was significantly higher than under the other treatments (P <0.05),while the contents of dissolved organic carbon (DOC),light fraction organic carbon (LFOC)and soil microbial biomass carbon (SMBC)in lower soil layer under sparse intercropping (SP)were higher than under the other treatments.Intercropping density was significantly negatively correlated with total organic carbon (TOC)and rapidly oxidized organic carbon (ROC).There was a significant negative correlation between the intercropping density and dissolved organic carbon (DOC),light fraction organic carbon (LFOC) and soil microbial biomass carbon (SMBC).In addition,there was a significant positive correlation among dif-ferent fractions of labile carbon.Citrus tree/Stropharia mushrooms intercropping enhanced the soil carbon pool management index in the upper soil layer,but decreased the same index in the lower soil layer.Citrus tree/Stropharia mushrooms intercropping enhanced formation and accumulation of soil labile carbon and in-creased soil carbon storage in this soil type in the Three Gorges Reservoir region.