Submitted to: Proceedings of the Brazilian Socity of Humic Substances
Publication Type: Proceedings
Publication Acceptance Date: 6/5/2004
Publication Date: 7/25/2004
Citation: Cary, T.J., Palazzo, A.J., Bashore, T.L., Senesi, N., Brunetti, G., Clapp, C.E., Clapp, J.J., Hayes, M., Schmidt-Rohr, K., Mao, J.D. 2004. Isolation and characterization of humic substances from soils collected at juniper butte range, idaho. Proceedings of the Brazilian Socity of Humic Substances. p. 175-177. Interpretive Summary: Humic substances, the main organic matter in soils, can be related to restoring native plants. We are characterizing native humic acids in soils from the Juniper Butte Range (JBR), Idaho, and identifying organic compounds that may promote the establishment of slickspot peppergrass seedlings. This plant is considered by some to be rare and, therefore, our broad objective is to find efficient methods to restore this species. Our objectives in this study were to isolate and characterize humic acids in JBR soils and relate this information to soil type and climate, prior to plant growth experiments. The composition of the slickspot humic acids fall within the range of those commonly reported for other similar soils. Carbon and nitrogen contents of the humic acids decrease with depth, and oxygen increases with depth. Carbon isotope values are characteristic of grass-type plants. The nuclear magnetic resonance and infra-red spectra indicate that the humic acids are composed of four major components: peptides, lipids, sugars, and ring carbons. Differences were also noted between samples sites for carbohydrates and amino acids. We concluded that the major components of the humic acids are from bacterial cell walls. Impact from this research will be felt by environmentalists, scientists and the general public as these humic materials are used to help restore and save the native plant 'slickspot peppergrass'.
Technical Abstract: Naturally-occurring humic substances in soils hold promise as a factor related to restoring native plants. We have characterized the humic acids (HAs) of the Juniper Butte Range (JBR) soils, in Idaho, and determined carbon compounds that may promote the establishment of slickspot peppergrass (Lepidium papilliferum) seedlings. Research included isolation and characterization of JBR soils in terms of HA content and relating this information to soil type and climate. Humic acids were extracted using a modified IHSS method, and isolated by membrane filtration, precipitated, dialyzed, and freeze-dried. Elemental analyses showed minor differences between HAs, with surface samples having higher C and N values. Differences were also noted between sample sites for carbohydrates, amino acids, and acidity components. FTIR, fluorescence and CPMAS 13C-NMR spectra provided valuable characterization and compositional information.