| 摘要: |
| 【目的】探讨农田转变为果园后土壤有机碳含量和组成的变化，为了解不同利用方式下土壤有机碳变化和长武地区土壤碳库的演变提供参考。【方法】以位于黄土高原南部沟壑区陕西长武地区塬面上的农田和不同树龄（≤5年、＞5年～≤15年、＞15年）的果园为研究对象，对其0～200 cm土层土壤有机碳的组成、剖面分布、储量等进行分析。【结果】农田转变为果园后，土壤总有机碳和易氧化有机碳的含量在树龄＞15年果园中分别下降了22.55%和25.79%，差异均达到显著水平（P<0.05）。树龄＞15年果园土壤紧结合态有机碳含量与农田相比下降了25.08%（P<0.05）。土壤总有机碳、稳结合态有机碳及紧结合态有机碳含量在0～200 cm土层总体呈“S”型分布。树龄＞15年果园与农田、树龄≤5年及树龄＞5年～≤15年果园相比，其0～100 cm土层土壤紧结合态有机碳含量和100～200 cm土壤松结合态有机碳含量均较低。与农田相比，树龄＞15年果园的土壤总有机碳储量显著降低（P<0.05），下降幅度为22.35%。【结论】农田转变为果园后，土壤总有机碳、易氧化有机碳含量及有机碳储量下降，且随着树龄的增加，以上3个指标明显降低；总有机碳及结合态有机碳含量在0~200 cm土层分布差异明显。 |
| 关键词: 土壤 土壤有机碳 易氧化有机碳 结合态有机碳 |
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| 基金项目:国家“十二五”科技支撑计划项目(2012BAD14B11)；陕西省科技统筹计划项目(2011KTDZ02-01) |
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| Changes in soil organic carbon after the conversion of farmland to orchard |
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ZHAO Shi-xiang,ZHANG Xue-chen,WANG Meng,et al
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| Abstract: |
| 【Objective】Changes in composition and content of soil organic carbon (SOC) after the conversion of farmland to orchard were investigated in Changwu region,Shaanxi province.【Method】The experiment sites were located in the southern gully area of the Loess Plateau and the content,distribution and composition of SOC in soil layer of 0-200 cm of farmland and orchards with different ages (≤5 years old,>5-≤15 years old,and >15 years old) were measured.【Result】Contents of SOC,readily oxidized organic carbon (ROC),and tightly combined organic carbon decreased by 22.55%,25.79%,and 25.08% after the conversion of farmland to orchard for >15 years,respectively （P<0.05）.Distribution of total SOC,ROC,and tightly combined organic carbon in soil layer of 0-200 cm was in “S” shape and contents of them in >15 years old orchards were lower than that of farmland and other orchards.Organic carbon storage decreased as the increase of orchard age.The organic carbon storage in farmland was 22.35% higher than that in >15 years old orchards.【Conclusion】After the conversion of farmland to orchard,the contents of SOC,ROC and organic carbon storage decreased as the increase of orchard age and the differences in distribution of SOC and combined organic carbon in soil layer of 0-200 cm increased. |
| Key words: soil soil organic carbon readily oxidized organic carbon combined organic carbon |
