Source: UNIVERSITY OF MAINE submitted to
SURFACE CHEMISTRY OF SOIL PHOSPHORUS-ORGANIC MATTER INTERACTIONS: AN ATOMIC FORCE MICROSCOPY & ULTRAHIGH RESOLUTION MASS SPECTROMETRY STUDY
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1003025
Grant No.
2013-67019-21368
Cumulative Award Amt.
$437,000.00
Proposal No.
2013-02823
Multistate No.
(N/A)
Project Start Date
Sep 1, 2013
Project End Date
Aug 31, 2017
Grant Year
2013
Program Code
[A1401]- Foundational Program: Soil Health
Recipient Organization
UNIVERSITY OF MAINE
(N/A)
ORONO,ME 04469
Performing Department
Plant, Soil, & Environ. Sci.
Non Technical Summary
Molecular scale information is needed to improve our understanding of the factors that control the bioavailability of soil P and stabilize terrestrial carbon in the form of soil organic matter (OM). We hypothesize that both of these important ecosystem processes are controlled through surface change and fractional coverage ratios of P and OM. This work couples two state-of-the-art chemical techniques, ultrahigh resolution mass spectrometry and atomic force microscopy, to elucidate the processes involved in P sorption and dynamic microbial decomposition reactions at the molecular scale. We will use these two analytical methods to examine the chemical mechanisms by which P and OM interact in both soil solution and on soil mineral surfaces to control quantity of P available to crops and stabilize the level of soil organic matter needed to maintain and increase soil health and quality. Our use of a range of OM sources typically used in sustainable management practices in studies conducted under controlled laboratory conditions allows us to explore the ways in which the molecular chemical surface environment and the chemical composition of OM combine to control effects of P-OM interactions observable at the field -scale. Our studies will build on a modern understanding of soil OM as we will examine the chemistry of labile, soluble fractions of OM and the configuration of sorbed organic matter affects its susceptibility to microbial decomposition. We hypothesize that the chemistry of soluble OM changes dynamically as decomposition proceeds, and we will explore these changes at the molecular level.
Animal Health Component
15%
Research Effort Categories
Basic
85%
Applied
15%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
10201102000100%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
0110 - Soil;

Field Of Science
2000 - Chemistry;
Goals / Objectives
1. Directly determine the effects of adsorbed P and OM on surface charge of model metal oxide and clay fractions of soil using AFM and its subsequent influence on sorption reactivity. [Physical and Chemical Processes] 2. Use ESI-and APPI-FT-ICR-MS to characterize water soluble OM pre- and post-sorption onto iron and aluminum oxide surfaces. [Chemical and Physical Processes] 3. Use greenhouse sand-culture microcosm bioassays to investigate P-OM interactive effects on P bioavailability. [Biological and Chemical Processes] 4. Determine the decomposition kinetics of adsorbed OM as a function of surface P coverage using CO2 evolution. [Biological, Physical, and Chemical]
Project Methods
We will continue to use ultrahigh resolution electrospray mass spectrometry (ESI-FT-ICR-MS) to characterize the organic matter used in the research. For the surface characterization, atomic force microscopy using functionalized tips will be used to probe the prevalent forces on the soil mineral surfaces with and without organic matter and phosphorus. We will use laboratory-based bioassays and CO2 incubations to determine how adsorption to surfaces affect two important ecosystem processes: phosphorus bioavailability to plants and the stabilization of soil carbon. Publication in first-tier journals and discussions at scientific conferences will be used to deliver our findings. Evaluation of the success of the delivery can be directly assessed using the number of citations that our publications receive as our peer researchers publish their works.

Progress 09/01/13 to 08/31/17

Outputs
Target Audience:Researchers in soil organic matter. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Publications in high impact journals have been selected to publish our resulting manuscript. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? All experiments have been sucessfully acomplished.

Publications

  • Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Chass�, A.W. and T. Ohno. 2016. Higher molecular mass organic matter molecules compete with orthophosphate for adsorption to iron (oxy)hydroxide. Environ. Sci. Technol. 50:7461-7469


Progress 09/01/15 to 08/31/16

Outputs
Target Audience:The target audience for this project consists of researchers active in both fundamental soil organic matter chemistry interested in its chemical characterization, as well as ecologists interested in how organic matter is involved in critical ecosystem processes and services. Furthermore, agroecologists involved in improving cropping systems with regard to soil quality and health, as well as climate change scientists interested in soil carbon sequestration will be a target for the outcomes of this research. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The competition between orthophosphate and water-extractable organic matter (WEOM) for adsorption to iron (oxy)hydroxide mineral surfaces is an important factor in determining the plant bioavailability of P in soils. Chemical force spectroscopy was used to determine the binding force between orthophosphate and iron (oxy)hydroxide that was coated onto atomic force microscopy (AFM) tips and adsorbed with WEOM. The chemical composition of the WEOM was determined by ultrahigh resolution electrospray ionization Fourier transform ion cyclotron mass spectrometry. The results indicate a correlation between aromatic WEOM molecules that are greater than 600 Daltons and the reduced binding force of orthophosphate to WEOM-adsorbed iron (oxy)hydroxide AFM tips suggesting that the molecular mass of aromatic WEOM molecules plays a critical role in regulating the WEOM-P interactions with surface functional groups of minerals. Based on the results of this study, we show the importance of obtaining a detailed, molecular-scale understanding of soil processes that can help develop better management strategies to reduce waste of limited P resources and adverse environmental impacts. Specifically, soil amendments with greater content of high molecular mass aromatic components may positively affect P use efficiency in soils by maintaining P is soil solution.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Ohno, Tsutomu; Sleighter, Rachel L.; Hatcher, Patrick G. Comparative study of organic matter chemical characterization using negative and positive mode electrospray ionization ultrahigh-resolution mass spectrometry. ANALYTICAL AND BIOANALYTICAL CHEMISTRY Volume: 408 Issue: 10 Pages: 2497-2504
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Chasse, Alexander W.; Ohno, Tsutomu; Higgins, Steven R.; Amirbahman, A.; Yildirim, N.; Parr, T.B. Chemical Force Spectroscopy Evidence Supporting the Layer-by-Layer Model of Organic Matter Binding to Iron (oxy)Hydroxide Mineral Surfaces. ENVIRONMENTAL SCIENCE & TECHNOLOGY Volume: 49 Issue: 16 Pages: 9733-9741


Progress 09/01/14 to 08/31/15

Outputs
Target Audience:The target audience for this project consists of researchers active in both fundamental soil organic matter chemistry interested in its chemical characterization, as well as ecologists interested in how organic matter is involved in critical ecosystem processes and services. Furthermore, agroecologists involved in improving cropping systems with regard to soil quality and health, as well as climate change scientists interested in soil carbon sequestrationwill be a target for the outcomes of this research. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? 1. The adsorption of OM to metal (oxy)hydroxide mineral surfaces is a critical step for C sequestration in soils. Chemical force spectroscopy revealed differing adhesion strengths of OM extracted from three soils and a reference peat soil material to an iron (oxy)hydroxide mineral surface. The results indicate that carboxyl-rich aromatic and N-containing aliphatic molecules of OM are correlated with high adhesion forces. Increasing molecular mass was shown to decrease the adhesion force between the mineral surface and the OM. Kendrick mass defect analysis suggests that mechanisms involving two carboxyl groups results in the most stable bond to the mineral surface. 2. We have shown that the combined use of negative-ion and positive-ion mode electrospray ionization (ESI) for the ultrahigh resolution mass spectrometry expands the analytical window for OM characterization. The OM components that are unique to positive-ion mode ESI are higher in molecular weight and are predominately classified as aliphatic compounds.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Parr, T.B., C.S. Cronan, T.Ohno, S.E.G. Findlay, S.M.C. Smith, and K.S. Simon. 2015. Urbanization changes the composition and bioavailability of dissolved organic matter in headwater streams. Limnol. Oceanogr. 60:885-900.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: de Oliveira, C.M.B., M.S. Erich, L.C. Gatiboni, and T.Ohno. Phosphorus fractions and organic matter chemistry under different land use on Humic Cambisols in Southern Brazil. Geoderma Regional 5:140-149.


Progress 09/01/13 to 08/31/14

Outputs
Target Audience: The target audience for this project consists of researchers active in both fundamental soil organic matter chemistry interested in its chemical characterization, as well as ecologists interested in how organic matter is involved in critical ecosystem processes and services. Furthermore, agroecologists involved in improving cropping systems with regard to soil quality and health will be a target for the outcomes of this research. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Past studies have shown that organic matter (OM) can reduce P sorption, presumably through competition for sorption sites on mineral surfaces. 31P-NMR and ultrahigh resolution mass spectrometry was used to investigate the chemical details of the P-OM interaction using 12 soils from a lowbush blueberry (Vaccinium angustifolium) management systems study. The 31P-NMR results show that organically managed soils had lower inorganic to organic ratios of soil P (0.9), as compared to the conventionally managed soils (4.6). The mass spectrometry analysis indicated that aromatic and highly unsaturated components comprised 77% of the pyrophosphate-extractable OM pool. Spearman’s rank correlation analysis of the 31P-NMR and ultrahigh resolution mass spectra identified 191 OM components which were positively correlated to the relative orthophosphate-P content. van Krevelen diagram analysis indicated that these 76% of these components were carboxylic-rich alicyclic molecules. This suggests that an effective management strategy for increasing the bioavailability of native soil P would be to utilize organic amendments that have a high percentage of carboxylic-rich alicyclic molecules components which compete with orthophosphate for sorption sites resulting in higher P concentrations in soil solution.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Ohno, T., T.B. Parr, M.-C.I. Gruselle, I.J. Fernandez, R.L. Sleighter, and P.G. Hatcher. 2014. Molecular Composition and Biodegradability of Soil Organic Matter: A Case Study Comparing Two New England Forest Types. Environ. Sci. Technol. 48:7229-7236.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Parr, T.B., T.Ohno, K.S. Simon, C.S. Cronan. 2014. comPARAFAC: A library and tools for rapid and quantitative comparison of dissolved organic matter components resolved by PARAFAC analysis. Limnol. Oceanogr. Methods. 12:114-125.