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W T Lopes da Silva soil carbon analysis methods july 2010

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W T Lopes da Silva soil carbon analysis methods july 2010

  1. 1. Wilson Tadeu Lopes da Silva1, Débora Marcondes Bastos Pereira Milori1, Ladislau Martin-Neto1,2, Adolpho José Posadas1,3, Aline Segnini1,3, Roberto 1 Quiroz3 1- Brazilian Agricultural Research Corporation (Embrapa) – Embrapa Agricultural Instrumentation Center – São Carlos/SP, Brazil. 2- Virtual Laboratories of Embrapa abroad – Labex – Beltsville/MD, USA 3- International Potato Center (CIP) – Lima, Peru. Rome – Italy 13 July 2010
  2. 2. 2 • Does the determination of Carbon content in the soil, satisfactory for analysis of balance of carbon in agriculture areas? • Do the actual laboratory analyses adequate in terms of practice, representativity, costs, etc.?
  3. 3. 3 Our proposal •To use Fluorescence parameters to produce a quick indicator for changes in structure of SOM; •Measure this indicator using whole soil; We built an apparatus to evaluate the feasibility of using laser-induced fluorescence spectroscopy (LIFS) for whole soil analysis
  4. 4. 4 Portable Laser-Induced Fluorescence Spectroscope Optical Bunddle Profile Excitation Fibers Emission Fiber Laser Miniature spectrometer Filter Optical bunddle Lap-top soil Miniature spectrometer Segnine, A.; Milori, D.; et al. Spectroscopic assessment of soil organic matter in wetlands from the high Andes, accepted in Soil Science Society of America Journal
  5. 5. 5 Portable LIFS system
  6. 6. 6 Portable LIFS system
  7. 7. HLIF = Humification Index 7 Laser-Induced Fluorescence Spectroscopy 400 450 500 550 600 650 700 3 2 1 0 NATURAL SOIL HEATED SOIL (600°C) Intensity (a.u.) λ (nm) HLIF = Area C Milori et al.. Soil Science Society of America Journal 70 (1): 57-63 JAN-FEB 2006
  8. 8. 8 Laser-Induced Fluorescence Spectroscopy 3.0 2.5 2.0 1.5 1.0 0.5 R=0.85; P<0.0001 0.05 0.10 0.15 0.20 0.25 0.30 HLIF ( Whole Soil) A4/A1 (HA in solution) Milori et al.. Soil Science Society of America Journal 70 (1): 57-63 Jan-Feb 2006 Segnini, A.; Milori, D.; et al. Soil Science Society of America Journal. Acepted to be published.
  9. 9. 9 Sample preparation soil samples from experimental area manual cleaning, and after the samples are sieved 15 ton of pressure 3 pellets of each sample (1 g) Cost equipment ~ US$ 30.000,00 Cost / Analysis : US$ 0.50
  10. 10. 10 Portable LIFS system Advantages - Faster and cleaner process; - Low cost; - It is possible a large scale measurements; - Allow analyses of SOM near its natural state; - Contribution of Humin is taking into account in the analyses; - To allow evaluation of changes in SOM according to soil management. Disadvantages - It is not a selective technique. It is difficult to identify structures; - Quenching effect due to interaction with metal can occur; - For organic soils it is necessary to take care with Inner Filter Effect.
  11. 11. To quantify soil carbon in a clean and agile way using methods economically viable 11 ¾¾Determination by Near Infrared Spectroscopy (NIRS) ¾¾Texture (Sand, Clay, and Silt) ¾¾Soil organic matter ¾¾Microbial activity ¾¾Determination by Laser Induced Breakdown Spectroscopy (LIBS)
  12. 12. 12 What is LIBS? ¾¾Laser Induced Breakdown Spectroscopy (LIBS) is an emerging analytical technique based on atomic and ionic emission of elemental sample constituents. ¾¾During the LIBS analytical process the sample is irradiated by a highly energetic laser pulse and absorbs this energy. The high temperature of ablated material generates a small plasma plume. As result of the temperature, the ablated material breaks down into excited ionic and atomic species. sample Pulsed laser emission Plasma
  13. 13. 13 What is LIBS? ¾¾During the plasma cooling, the excited species return to their ground state emitting electromagnetic radiation in characteristic wavelengths. ¾¾In this sense, the analysis of sample emission spectra gives a qualitative view of sample elemental composition.
  14. 14. 14 Soil pellet coin
  15. 15. 15 Laser 1064 nm LIBS apparatus Focuses lens Plasma Sample Fiber optics spectrometer Computer Use of Artificial Neural Network (ANN)
  16. 16. 16 Embrapa systems Bench Portable Spectrometers manufactured by Ocean Optics model LIBS2500 spectral range: 188-980 nm Resolution: 0.1 nm Laser manufactured by Quantel model Big Sky Laser Ultra50 single-pulse energy 50 mJ pulse duration 8ns Delay time: 3 μs Spectrometers manufactured by StellarNet Inc model LIBS2500 spectral range: 190-1000 nm Resolution: 0.2 nm Laser manufactured by Kigre Inc. model MK-367 single-pulse energy 20 mJ pulse duration 4ns Delay time: 2 μs
  17. 17. 17 Typical soil emission –– C region 350 300 250 200 150 100 50 0 C Al 190 192 194 196 198 200 Intensidade (u.a.) Comprimento de Onda (nm) wavelength (nm) Da Silva, R, Milori, D. et al.. Spectrochimica Acta. Part B, Atomic Spectroscopy. , v.63, p.1221 - 1224, 2008.
  18. 18. 18 LIBS + Artificial Neural Network for Carbon analysis 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,1 1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0,0 C(%) LIBS/MLP C (%) TOC R=0.93 LOD: 0,3% C reference concentration (%) C predicted concentration (%) Absolute Error 0.51 0.43 (±0.04) -0.08 0.79 0.94 (±0.08) 0.15 0.62 0.78 (±0.15) 0.16 0.48 0.56 (±0.09) 0.08 0.65 0.76 (±0.10) 0.11 0.36 0.44 (±0.07) 0.08 0.45 0.51 (±0.07) 0.06 0.72 0.76 (±0.07) 0.04
  19. 19. 19 LIBS + ANN 0 1 2 3 4 5 6 7 8 9 250 200 150 100 50 0 Ba (mg kg-1) Validation Samples ICP OES LIBS 0 1 2 3 4 5 6 7 8 9 10 100 80 60 40 20 0 Co (mg kg-1) Validation samples ICP OES LIBS 0 1 2 3 4 5 6 7 8 9 10 250 200 150 100 50 0 Cu (mg kg-1) Validation samples ICP OES LIBS Co 0 1 2 3 4 5 6 7 8 9 10 2000 1800 1600 1400 1200 1000 800 600 400 200 0 Mn (mg kg-1) Validation samples ICP OES LIBS Ba Cu Mn
  20. 20. 20 Sample preparation soil samples from experimental area manual cleaning, and after the samples are sieved 15 ton of pressure 1 pellet of each sample (1 g) Cost equipment ~ US$ 50.000,00 Cost / Analysis : US$ 0.50
  21. 21. 21 Soils & Humic Substances Leader: Dr. Ladislau Martin-Neto Research team: Débora Milori Silvio Crestana Wilson T. L. da Silva Marcelo L. Simões Carlos Vaz Luiz A. Colnago Ednaldo Ferreira Adolfo Posadas Roberto Quiroz Pos-doc: Edilene C. Ferreira Aline Segnini Students Cleber Hilário dos Santos Bruno H. Martins Lilian F. de Almeida Lívia Favoretto Mariani Mussi Camila Carvalho André Venâncio Marcelo Cardinalli Mariana Russo Marina França-Silva Bruna D.L. Pinto Thais Oahshi Lilian F. de Almeida Tatiana M. Ferrarezi Partnerships:
  22. 22. 22 Acknowledgements
  23. 23. 23 www.cnpdia.embrapa.br wilson@cnpdia.embrapa.br

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