|Zhang, Hailin -|
Submitted to: International Symposium on Soil Organic Matter Dynamics: Land Use, Management and Global Change
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2011
Publication Date: July 11, 2011
Citation: He, Z., Zhang, H. 2011. Soil organic matter composition affected by potato cropping managements. Abstracts of the 3rd International Symposium on Soil Organic Matter Dynamics: Land Use, Management and Global Change. July 11-14, 2011, Leuven, Belgium. p. 239. Technical Abstract: Organic matter is a small but important soil component. As a heterogeneous mixture of geomolecules and biomolecules, soil organic matter (SOM) can be fractionated into distinct pools with different solubility and lability. Water extractable organic matter (WEOM) fraction is the most labile and mobile fraction of all SOM fractions in the soil. Sodium pyrophosphate extractable organic matter (PEOM) fraction is a relatively labile SOM pool. To investigate the impact of management practices on SOM compositions, we sequentially extracted WEOM and PEOM from 10 field soils which had three-year rotations of potato with other crops with or without irrigation. Elemental analysis indicated that irrigation increased the Na content in WEOM, but decreased P, Al, and Fe contents in PEOM. Comparison of FT-IR spectra indicated that nitrate and phosphate contributed to FT-IR spectra features of undialyzed water extracts (i.e. untreated WEOM) but not the dialyzed extracts. Otherwise, the FT-IR spectra of untreated and treated WEOM samples should be comparable. Semi-quantitative analysis of FT-IR spectra indicated that PEOM was more enriched in aliphatic, carboxyl and aromatic compounds than those of WEOM. However, the 3-yr crop rotations and irrigation changed the relative abundances of these functional groups only in WEOM, not in PEOM. This observation suggests that the most labile SOM fraction WEOM is a more suitable indicator on the short-term impact of crop management practices on SOM.