摘要
摘要:农田土壤有机碳气体交换与径流损失的研究大都相对孤立, 对二者之间的同步观测研究较少。本文利用紫色土坡地可测壤中流的径流小区, 开展了不同施肥处理下紫色土农田土壤有机碳土-气交换和土-水界面迁移过程的同步观测试验。试验处理包括: 无肥对照(CK)、常规氮磷钾(NPK)、猪厩肥配施氮磷钾(OMNPK)、秸秆配施氮磷钾(RSDNPK)。结果表明: 1)不同施肥处理的土壤异养呼吸速率与通量均呈现: RSDNPK>OMNPK>NPK>CK, 表明施加无机肥、有机肥和秸秆还田均会增加紫色土的土壤CO₂排放, 其中秸秆还田配施氮磷钾肥的CO₂排放通量为4155.87 kg(C)?hm^?2, 显著大于其他施肥处理。2)不同施肥处理的土壤有机碳径流损失通量表现为: RSDNPK>OMNPK>CK>NPK, 径流损失途径也存在差异, 与CK相比, RSDNPK处理在降低紫色土泥沙损失通量的同时, 显著增加了壤中流可溶性有机碳(DOC)损失通量, 达8.29 kg(C)?hm^?2, 各施肥处理的壤中流DOC损失通量占径流碳损失总通量的49.82%~92.11%, 说明壤中流DOC损失是紫色土有机碳径流损失的主要方式。3) RSDNPK处理的土壤有机碳损失总通量显著大于其他施肥处理, OMNPK与NPK处理的总通量没有显著差异； 各施肥处理的CO₂排放通量占总通量的比例均大于99%, 说明气态损失是紫色土有机碳损失的主要途径。4)本文计算了不同施肥处理的单位产量碳损失通量, 将作物经济效益与生态环境负荷相结合, 结果表明CK的单位产量碳损失通量显著大于其他3个施肥处理。OMNPK处理的土壤有机碳含量为5.86 g?kg^?1, 大于NPK处理, 说明施加有机肥有利于土壤有机碳的积累, 因此在紫色土地区可以优先考虑施加有机肥配施氮磷钾肥。
关键词:施肥/
紫色土/
CO₂排放通量/
可溶性有机碳/
地表径流/
壤中流
Abstract:Studies on organic carbon gas exchange and runoff loss in farmland soil are relatively isolated, and the synergy between the two pathways is poorly understood. In this study, simultaneous tests of organic carbon gas exchange and soil–water interface migration process of purple soil under different fertilization treatments were conducted using a runoff plot that allowed interflow observation. The experimental treatments included no fertilizer (CK), chemical fertilizer (nitrogen, phosphorus, and potassium; NPK), pig manure plus synthetic NPK fertilizer (OMNPK), and the incorporation of crop residues plus synthetic NPK fertilizer (RSDNPK). The results showed that 1) the soil respiration rate and carbon dioxide (CO₂) emission flux under different fertilization treatments were RSDNPK > OMNPK > NPK > CK, indicating that the application of chemical fertilizer, organic fertilizer, and straw returning increased the soil respiration rate of purple soil. The CO₂ emission flux of RSDNPK was 4155.87 kg(C)?hm^?2, significantly higher than those of the other fertilization treatments. 2) The soil organic carbon runoff loss flux was in the order of RSDNPK > OMNPK > CK > NPK, and there were differences in the runoff loss pathways under different fertilization treatments. RSDNPK reduced sediment erosion and significantly increased the flux of dissolved organic carbon (DOC) loss in the interflow, reaching 8.29 kg(C)?hm^?2. The DOC loss flux of the interflow accounted for 49.82%–92.11% of the total runoff carbon loss flux under different fertilization treatments, indicating that interflow was the main pathway of soil organic carbon loss in purple soil. 3) The total fluxes of soil organic carbon loss under RSDNPK were significantly higher than those under other fertilization treatments, which was not significantly different between OMNPK and NPK. The proportion of CO₂ emission fluxes to the total fluxes was more than 99% in each fertilization treatment, indicating that gaseous loss was the main mechanism of organic carbon loss in purple soil. 4) We calculated the carbon loss flux per unit yield for each fertilization treatment and combined the economic benefits with the ecological environmental load. The results showed that the carbon loss flux per unit yield in CK was significantly higher than that in other fertilization treatments. The soil organic carbon content of the OMNPK treatment was 5.86 g?kg^?1, greater than that of NPK, indicating that organic fertilizer application is beneficial to the accumulation of soil organic carbon. OMNPK should thus be prioritized in the purple soil area.
Key words:Fertilization/
Purple soil/
CO₂ emission flux/
Dissolved organic carbon/
Surface flow/
Interflow



PDF全文下载地址:

http://www.ecoagri.ac.cn/article/exportPdf?id=3f59f2fd-22ac-4e04-9330-50e366368792