¹⁴C-labeled organic amendments: Characterization in different particle size fractions and humic acids in a long-term field experiment

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• 作者：Michael Tatzber^a ; ^{michael.tatzber@boku.ac.at} ; Michael Stemmer^b ; Heide Spiegel^b ; Christian Katzlberger^b ; Claudia Landstetter^b ; Georg Haberhauer^c ; Martin H. Gerzabek^a
• 关键词：Cropping system ; Farmyard manure ; Silt- ; clay-sized particles ; Mid-infrared spectroscopy ; Fluorescence spectroscopy ; Photometry
• 刊名：Geoderma
• 出版年：2012
• 期刊代码：28_00167061
• 类别：ear
• 出版时间：May, 2012
• 卷：177-178
• 期：Complete
• 页码：39-48
• 文件大小：734 K

摘要

Knowledge about the stabilization of organic matter input to soil is essential for understanding the influence of different agricultural practices on turnover characteristics in agricultural soil systems. In this study, soil samples from a long-term field experiment were separated into silt- and clay-sized particles. In 1967, ¹⁴C labeled farmyard manure was applied to three different cropping systems: crop rotation, monoculture and permanent bare fallow. Humic acids (HAs) were extracted from silt- and clay-sized fractions and characterized using photometry, mid-infrared and fluorescence spectroscopy. Remaining ¹⁴C was determined in size fractions as well as in their extracted HAs. Yields of carbon and remaining ¹⁴C in HAs from silt-sized particles and C_org in clay-sized particles decreased significantly in the order: crop rotation > monoculture 鈮?#xA0;bare fallow. Thus, crop rotation not only had the largest overall C-pool in the experiment, but it also best stabilized the added manure. Mid-infrared spectroscopy could distinguish between HAs from different particle size soil fractions. With spectroscopic methods significant differences between the cropping systems were detectable in fewer cases compared to quantitative results of HAs (yields, ¹⁴C, C_org and N_t). The trends, however, pointed towards increased humification of HAs from bare fallow systems compared to crop rotation and monoculture as well as of HAs from clay-sized particles compared to silt-sized particles. Our study clearly shows that the largest differences were observed between bare fallow on one hand and monoculture and crop rotation on the other.