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试验采集不同种植年限设施菜地土壤样品,测定土壤有机质(SOM)、可溶性有机碳(DOC)、胡敏酸(HA)、富里酸(FA)、微生物量碳(MBC)、微生物商(C_(mic)-to-C_(org))、C矿化和E4/E6值等指标,结合傅立叶变换红外光谱技术解析不同种植年限土壤有机质组成与结构变化的规律。结果显示,随着种植年限的增加,SOM、DOC、HA、HA/FA、MBC、C_(mic)-to-C_(org)、E4/E6值、C矿化率和CO_2释放速率均出现明显下降趋势,其中MBC、C_(mic)-to-C_(org)、C矿化率、CO_2释放速率和HA/FA在种植6 a时下降最明显,之后变化缓慢。与露天农田土壤(CK)相比,设施菜地呈现较高的SOM、DOC、Humus、HA、FA、HA/FA和E4/E6。胡敏酸红外光谱图谱显示设施菜地种植20 a处理土壤芳构化程度高,结构稳定,难以降解,其他三种种植年限(3 a、6 a和10 a)的芳构化程度相对较低,脂肪族成分相对较高。综上可知,设施菜地土壤有机质组成与结构随着种植年限的增加具有规律性变化,结果加深了对设施菜地土壤有机质演变规律的认知。
The soil organic matter (SOM), dissolved organic carbon (DOC), humic acid (HA), fulvic acid (MBC), microbe (C_ mic) -to-C_ (org)), C mineralization, E4 / E6 and other indicators, combined with Fourier transform infrared spectroscopy analysis of the composition of soil organic matter composition and structural changes in different planting years. The results showed that the SOM, DOC, HA, HA / FA, MBC, C_ (mic) -to-C_ (org), E4 / E6 value, C mineralization rate and CO 2 release rate all increased with the increase of planting years MBC, C_ (mic) -to-C_ (org), C mineralization rate, CO 2 release rate and HA / FA decreased most obviously at 6 years of planting, and then changed slowly. Compared with open farmland soils (CK), the vegetable fields show higher SOM, DOC, Humus, HA, FA, HA / FA and E4 / E6. The results of infrared spectra of humic acid showed that the soils were highly aromatic, stable and difficult to degrade in the 20-day vegetable cultivation soils. The aromatization degree of the other three planting years (3 a, 6 a and 10 a) was relatively low , The aliphatic component is relatively high. In summary, the composition and structure of soil organic matter in the vegetable garden have regular changes with the increase of planting years, and the result deepens the understanding of the evolution of soil organic matter in the vegetable garden.