Title: UV and fluorescence spectral features of water extractable organic matter of soils from manure application under different tillage Authors
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, M., Zhao, A., Zhang, H., Endale, D.M., Schomberg, H.H. 2011. UV and fluorescence spectral features of water extractable organic matter of soils from manure application under different tillage. Abstracts of the 3rd International Symposium on Soil Organic Matter Dynamics: Land Use, Management and Global Change. July 11-14, 2011, Leuven, Belgium. p. 202. Technical Abstract: Water extractable organic matter (WEOM) is generally regarded as the most labile form of soil organic matter fraction. There are many factors affecting quality and quantity of WEOM in soil. The objective of this study was to determine quantity and spectral properties of WEOM responding to types of nutrient addition and tillage managements. Soil samples were taken from treatments (conventional tillage, no tillage, poultry litter, and NH4NO3 application) of a 10 –year tillage experiment in Watkinsville Georgia at different times and soil depths. Air-dried soil samples were extracted by Millipore H2O followed by filtration (<0.45 µm), and soluble C, N, absorptivity of solution samples at 254 nm, solution fluorescence excitation and emission matrix (EEM) were determined. Results showed that manure application increased WEOM amounts in soil. Absorptivity at 254 nm decreased over cropping years for conventional tillage and NH4NO3 application indicating accumulation of aliphatic organic compounds in WEOM. However, different sources of nutrient addition and tillage did not affect fluorescence components of WEOM. This might be attributed to the fact that all WEOM in soil results directly or indirectly from soil biological activities. Less condensed, but ring structured N compounds (tyrosine-like fluorophores) are more mobile in soil and tend to be depleted in upper soil but accumulated in the lower soil depths. Further study is needed to verify if this portion of WEOM is the major contributor of WEOM to fresh or seawater ecosystem.