玉米秸秆腐解过程的红外光谱研究

STUDY ON DECOMPOSED CORN STRAW RESIDUE BYFOURIER TRANSFORM INFRARED SPECTROSCOPY

采用傅里叶变换红外光谱（ＦＴＩＲ）对玉米秸秆腐解过程进行了研究。由光谱变化的分析可见，随着腐解的进行，羟基、酮羰基、甲基、亚甲基和次甲基的含量逐渐降低，腐解产物的脂族性降低，芳香性趋于升高和增强，有机成分中的无机元素特别是硅释放出来，并以ＳｉＯ２等氧化物的形式逐渐积累，一些阳离子则形成羧酸盐和碳酸盐。羧基在腐解过程中皆形成羧酸盐。就秸秆中叶片和茎秆腐解变化的差异来说，叶片腐解产物中甲氧基的含量增加，茎秆中的甲氧基含量无明显变化。在腐解１８０天后，叶片中的有机硅化合物及木质素的分解显著，但茎秆中二者的变化较小。未腐解的叶片中无羧酸盐存在，而未腐解的茎秆中则存在羧酸盐。Ｎ肥的加入促进了玉米秸秆残体的腐解。叶片和茎秆混合堆腐的腐殖化系数远高于二者单独堆腐。

Fourier transform infrared spectroscopy (FTIR) was directly applied to study thedecomposition process of corn straw residue (CSR). The result showed that FTIRspectra could indicate the dynamic changes of organic components during thedecomposition process of CSR With the progress of CSR decomposition, hydroxyl,ketonic carbonyl, methyl, methylene, methine and aliphatic compounds decreased, butaromatic compounds increased. This meant that the carbohydrates and aliphaticcompounds decomposed quickly and lignin decomposed slowly. The inorganic elements,especially silicon, were reduced from the CSR and accumulated as oxides and someother inorganic elements were reacted with carboxyls to form carboxylates. In theprocess of decomposition, carboxyl existed as carboxylic ions, most carbohydrates andaliphatic compounds were oxidized to CO2 and H2O, the proteins and amino acidswere decomposed to CO2, NH+4 NO-3 and amides, and the lignin were decomposedto hydroquinones. As far as the differences between the leaf and the stem during thedecomposition process of CSR, methoxy increased in the leaf, however, no significantchanges were observed in the stem; the organic silicon compounds and lignindecomposed significantly in the leaf, but the change was little in the stem;undecomposed leaf didn' t contain carboxylic ions, on the contrary, carboxylic ionsexisted in undecomposed stem. During the decomposition process of CSR, addition ofN fertilizer promoted the decomposition progress of CSR The chemical analysesshowed that the humification index when the leaf and stem were mixed anddecomposed was higher than that when the leaf and stem were decomposed separately.