کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1196614 1492960 2016 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Response of humic acid structure to soil tillage management as revealed by analytical pyrolysis
ترجمه فارسی عنوان
پاسخ ساختار اسید هیدروکسیل به مدیریت خاک در خاک به وضوح با استفاده از تجزیه و تحلیل پیاپی تجزیه و تحلیل شده است
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
چکیده انگلیسی


• We show the potential of pyrolysis GC–MS in reflecting significant changes in the composition of soil organic matter under contrasted management practices.
• We discuss the pyrolytic alkyl compounds (fatty acids, alkenes and alkanes) as well as methoxyphenols assemblages as proxies to soil management.
• Humic acids from undisturbed – or minimum tillage – plots showed comparatively higher diagenetic transformation.
• Conservation tillage practices lead to increasing soil C levels, at expenses of the accumulation of recent organic matter derived either from altered lignins and/or microbial biomass.

The effects on the structural features of humic acids (HA) from dryland farming soils under long term management practices have been approached by analytical pyrolysis (Curie-point pyrolysis-gas chromatography/mass spectrometry, Py-GC/MS). The field experiments (started in 1987) include conventional, minimum and no-tillage plots, as well as non cultivated plots. The HAs isolated from the various plots showed significant differences in their pyrolytic behavior, in particular regarding the total abundances of alkyl pyrolysis compounds (fatty acids, alkenes and alkanes). The occurrence of very short-chain fatty acids (C5–C11) in uncultivated plots could be indicative of constitutional alkyl structures in the relictual HA from undisturbed soil. The effect of soil tillage managements substantially increased total abundances of fatty acids in plots under conservation practices (mainly no-tillage).The HAs from uncultivated soils showed the greatest percentages of alkanes and alkenes. This was associated to the increased proportions of even C-numbered alkene homologues from C12 to C18, possibly related to the incorporation of microbial compounds during the humification process. High percentage of alkylbenzenes and catechols were also characteristic of the uncultivated plots. The increased proportions of methoxyphenols, in special of the syringyl (dimethoxyphenyl) type, in HAs from plots subjected to conventional tillage pointed out to humification processes based on progressive alteration of plant lignins. From the viewpoint of soil quality, the results suggest comparatively advanced transformation stages of the HA from uncultivated plots, which means that conservation tillage practices seems to lead to increasing soil C levels, at expenses of the accumulation of comparatively recent organic matter derived either from altered lignins and/or microbial biomass.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Analytical and Applied Pyrolysis - Volume 117, January 2016, Pages 56–63
نویسندگان
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