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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #311704
Title: Elemental composition and functional groups in soil labile organic matter fractions

Author
item TAZISONG, IRENUS - Alabama A & M University
item SENWO, ZACHARY - Alabama A & M University
item He, Zhongqi

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/18/2015
Publication Date: 10/2/2015
Citation: Tazisong, I.A., Senwo, Z.N., He, Z. 2015. Elemental composition and functional groups in soil labile organic matter fractions.In: He, H, Wu, F., editors. Labile Organic Matter - Chemical Composition, Functions, and Significance in Soil and the Environment. SSSA Special Publication 62. Madison, WI:Soil Science Society of America. p. 137-156.

Interpretive Summary: Labile organic matter fractions are major components involved in nutrient cycle in soil. Literature on the chemical composition of, preferential metal binding with, and the effect of tillage, cropping, and manure applications on labile organic matter in ultisol is scanty. Therefore, as a case study, this chapter presents and discusses the data on different organic matter fractions in Alabama cotton soils (ultisol) amended with chemical fertilizer (NH4NO3) and poultry litter and managed as no-till, till, and mulch-till practices. The light fraction of soil organic matter was sensitive to organic matter changes, reflecting a transient property and short-term effects. Spectroscopic data reveal that cropping management practices mainly affect the active carbon functional groups with decreasing more stable aromatic groups. This observation suggests the incorporation of crop residues into humic fractions of soil organic matter.

Technical Abstract: Labile organic matter fractions are major components involved in nutrient cycle in soil. In this chapter, we examine three labile organic matter fraction: light fraction (LF), humic acid (HA) and fulvic acid (HA) in Alabama cotton soils (ultisol) amended with chemical fertilizer (NH4NO3) and poultry litter and managed as no-till, till, and mulch-till practices LF was significantly affected by management practices. On the average, the LF in the no-till soils was slightly higher 1.1± 0.012 (SD, n=4) g than in the conventional 0.99 g and mulch till 0.94 g. The C, N and S contents of the LF from the amended and till soils were higher than the control (bare fallow, BF) sample. Fourier transform infrared and solid-state C-13 nuclear magnetic resonance spectroscopy were applied to evaluate the effect of cropping management practices on the composition of soil humic substances. These spectral data show that the impacts of management practices on mainly on the carbonyl group from amide and carboxylic acid or ketone compounds for HA, and both carbonyl and aliphatic groups for FA. Cropping management practices also increased ketone, quinone, or aldehyde, and decreased aromatic C-C and C-H groups, compared to those of the BF HA sample. The aromaticity of HA samples decreased with cropping managements and fertilizer applications, suggesting incorporation of aliphatic crop residues to the HAs.