中文摘要：

土壤腐殖质是土壤中所特有的一类特殊的高分子化合物，具有重要的肥力和环境调节功能。其中胡敏素的提取和纯化很困难，从而限制了对其性质和结构的研究。为揭示胡敏素的结构性质，本研究按Pallo分组，将胡敏酸（HA）分为焦磷酸钠提取的胡敏酸（HAP）、氢氧化钠提取的胡敏酸（HAS）；富里酸（FA）分为焦磷酸钠提取的富里酸（FAP）和氢氧化钠提取的富里酸（FAS）；胡敏素（HM）分为铁结合胡敏素（HMi）、粘粒结合胡敏素（HMc）和不溶性胡敏素（HMr）三个组分，采用红外光谱法对黑土、草甸土以及黑土底土加入大量玉米秸秆培养后腐殖质各组分的结构特征进行研究。腐殖质各组分按Pallo法分组。结果表明：铁结合胡敏素（HMi）、粘粒结合胡敏素（HMc）与胡敏酸（HA）、富里酸（FA）具有相似的光谱特征，但存在明显差异。黑土、草甸土中HMi和HMc的脂族性强于HA和FA；HMi与HMc相比，HMi具有较高的脂族性。黑土中氢氧化钠提取的胡敏酸（HAS）的脂族性强于焦磷酸钠提取的胡敏酸（HAP）；NaOH提取的富里酸（FAS）的脂族性强于Na4P2O7提取的富里酸（FAP）。草甸土中HAP的脂族结构较多，而HAS脂族结构相对较少。在培养土中，新形成的FA脂族性强于HA、HMi和HMc组分。新形成的HMc脂族性强于HMi和HMc的脂族性强于HAP，而弱于HAS。

英文摘要：

Humus is a special compound with high molecule in soil. It has important function in soil fertility and entironment. In the humus, the humin fraction is hardly to extract and purify, this limiting the study of its nature and structure. To reveal the nature and structure of humin, according to the classification methed of Pallo, humic acid was divided into humic acid extracted with pyrophosphate of sodium （HAP） and humic acid extracted with sodium hydroxide （HAS） ; fulvic acid was divided into fulvic acid extracted with pyrophosphate of sodium （FAP） and fulvic acid extracted with sodium hydroxide （FAS）; humin was divided into humin linked to iron （HMi）, humin linked to clay （HMc） and humin residua （HMr）. Infrared spectrometry was applied to study the characters of humus fractions in black soil, meadow soil and black subsoil added large proportion corn stock. According to the classification method of Pallo, the result shows that humus fractions have the similar spectral characters, but with obvious difference. In black soil and meadow soil, the aliphatic structure of humin linked to iron （HMi） and humin linked to clay （HMc） are stronger than humic acid （HA） and fulvic acid （FA）. Compared to HMc, HMi has the higher aliphatic structure. In black soil, the aliphatic structure of humic acid extracted with NaOH （HAS） is stronger than that of humic acid extracted with pyrophosphate of sodium （HAP） ;Fulvic acid extracted with NaOH （FAS） is stronger than fulvic acid extracted with pyrophosphate of sodium （FAP）. In meadow soil, the aliphatic structure of HAP is stronger than that of HAS. In incubation soil, the aliphatic structure of FA which newly forms is stronger than HA and HM fractions which newly forms. The aliphatic structure of new formed HMc is stronger than that of HMi. The aliphatic structure of HMc is stronger than HAP, but is lower than that of HAS.