Pyrolis-gas chromatography to evaluate the organic matter quality of a mulched soil
Academic Article
Publication Date:
2007
abstract:
Pyrolysis-gas chromatography (Py-GC) permits to study the organic matter properties in bulk soil and requires few
manipulations with respect to the traditional methodologies based on extraction and fractionation processes. In this paper, Py-GC has been proposed as a quick and valuable technique to study the structural evolution of organic matter in a mulched soil.
A sandy clay loam soil (rendzina soil) was treated, under field conditions in the south-east of England, with organic (compost from dairy manure at the rates of 35 and 70 t ha_1, wheat straw at the rates of 2 and 4 t ha_1, plant residues representing the no-till treatment) and inert (black polyethylene) mulching materials. Nitrogen fertilization was considered as a traditional chemical treatment, while the control was an unmulched and no-fertilized soil. The objective of this research was to evaluate short-term (4 months) changes on chemico-structural properties of soil organic matter (SOM) and its trend towards mineralization and humification after mulching practices. Total and water-soluble C and N forms of the 010 cm layer were determined. Py-GC was used as a rapid and reproducible investigation technique (chemical probe) to characterize SOM. Pyrolytic humification and mineralization indices have been calculated. Compost increased the content of soil total and soluble C and N. On the other hand, straw mulched soil, due to straw being a poorly degradable material, showed both a relatively low N concentration of total and soluble forms and also the lowest concentration of water-soluble C (WSC). Pyrolytic data supported these results. Compost and straw treatments were characterized by low and high B/E3 indices, and high and low AL/AR ratios, respectively, suggesting the presence of more easily available organic components in compost mulched soils. Principal component analysis (PCA) confirmed that compost treatments were principally related to soluble C and N and labile organic compounds, while straw and no-till showed stable SOM. Control, N fertilization and polyethylene treatments showed a similar SOM composition, which was characterized by pyrolytic fragments derived mostly from microbially linked nitrogenated compounds. The pyrolysis technique is a promising method in the assessment of changes in SOM composition, even in complex and dynamic mulching systems.
manipulations with respect to the traditional methodologies based on extraction and fractionation processes. In this paper, Py-GC has been proposed as a quick and valuable technique to study the structural evolution of organic matter in a mulched soil.
A sandy clay loam soil (rendzina soil) was treated, under field conditions in the south-east of England, with organic (compost from dairy manure at the rates of 35 and 70 t ha_1, wheat straw at the rates of 2 and 4 t ha_1, plant residues representing the no-till treatment) and inert (black polyethylene) mulching materials. Nitrogen fertilization was considered as a traditional chemical treatment, while the control was an unmulched and no-fertilized soil. The objective of this research was to evaluate short-term (4 months) changes on chemico-structural properties of soil organic matter (SOM) and its trend towards mineralization and humification after mulching practices. Total and water-soluble C and N forms of the 010 cm layer were determined. Py-GC was used as a rapid and reproducible investigation technique (chemical probe) to characterize SOM. Pyrolytic humification and mineralization indices have been calculated. Compost increased the content of soil total and soluble C and N. On the other hand, straw mulched soil, due to straw being a poorly degradable material, showed both a relatively low N concentration of total and soluble forms and also the lowest concentration of water-soluble C (WSC). Pyrolytic data supported these results. Compost and straw treatments were characterized by low and high B/E3 indices, and high and low AL/AR ratios, respectively, suggesting the presence of more easily available organic components in compost mulched soils. Principal component analysis (PCA) confirmed that compost treatments were principally related to soluble C and N and labile organic compounds, while straw and no-till showed stable SOM. Control, N fertilization and polyethylene treatments showed a similar SOM composition, which was characterized by pyrolytic fragments derived mostly from microbially linked nitrogenated compounds. The pyrolysis technique is a promising method in the assessment of changes in SOM composition, even in complex and dynamic mulching systems.
Iris type:
01.01 Articolo in rivista
Keywords:
mulching; soil organic ; pyrolysis-gas-cromatography; mineralization; umification
List of contributors:
Macci, Cristina; Masciandaro, Grazia; Ceccanti, Brunello
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