DEVELOPMENT OF A STRUCTURED SET OF TOOLS FOR EVALUATION AND MANAGEMENT OF AGRICULTURAL RECYCLING OF ORGANIC RESIDUES AT LOCAL SCALE

(1)

20 40 60 80 100 20 40 60 80 100 N IR S p re d ic te d IRO C (% T O C )

Measured IROC(% TOC)

●Calibration samples: R² = 0.86

○Validation samples: R² = 0.83

Designation ( principle) ISO or other reference*

Preparation for physicochemical analyses ISO 11464

Dry matter (weight loss at 105°C) ISO 11465

Mineral N (KCl extraction and NO3 NH4 analyses) ISO 14256-2

OM content estimation (weight loss at ≤550°C) NF EN 13039

Total organic C (total C corrected for carbonate) ISO 10694, ISO 14235

Total carbonate (volume of out gassed CO2) ISO 10693

Total N (“Kjeldhal” or C-N analyser) ISO 11261 and NF EN 13654-1

Total element analyses (after strong acid or alkaline attack) ISO 11466, ISO 14869-1, ISO 14869-2

Available P2O5 (moderate alkaline extraction) ISO 11263

Available or exchangeable trace elements (extracted by EDTA or CaCl2) ISO 31120, ISO 10390

Total or extractible polyphenol Cirad, Montpellier

pH (in standard aqueous suspension) ISO 10390

Electric conductivity (of standard water extract) NF EN 13038

Near IR, Mid-IR and visible spectrometric characterisation

Van Soest fractionation (biochemical extractions) XP U 44-162

C & N mineralization potential (controlled incubation and measuring emitted CO2 and/or extractable mineral N)

ISO 14238, XPU 44-163 Microbial biomass (CHCl3 fumigation and measuring soluble C or amine N) ISO 14240-2

Chemical demand of oxygen ISO 15705 NF T 90-101

Presence or quantification of pathogens X33-017, X33-018, ISO 9308-3 and 7899-1

DEVELOPMENT OF A STRUCTURED SET OF TOOLS FOR EVALUATION AND MANAGEMENT

OF AGRICULTURAL RECYCLING OF ORGANIC RESIDUES AT LOCAL SCALE

de Junet A., Cambier P., Peltre C., Houot S., Gilliot J.-M., Michaud A., Parnaudeau V.

2

_,

Cazevieille P.

3

_{, Doelsch E.}

3

_{, Farinet J.L.}

3

_{, Saint-Macary H.}

3

_{, Nazaret S.}

4

_{, N’Dour Y.}

5

_{, Masse D.}

6

_{, Rafolisy T.}

7 UMR INRA-AgroParisTech “Environnement et Grandes Cultures”, 78850, Thiverval-Grignon, France, [email protected]

2_{UMR INRA-AgroCampusOuest SAS, Rennes, France}3_{Unité CIRAD “Risque environnemental lié au recyclage”, Montpellier, France}4_{UMR “Ecologie Microbienne”, Lyon, France} 5_{Institut Sénégalais de Recherches Agricoles, Dakar, Sénégal}6_{UMR IRD “Eco & Sols”, IRD, Dakar, Sénégal}7_{Laboratoire des Radioisotopes, Université d’Antananarivo, Madagascar}

1- INTRODUCTION

The development of integrated methods for optimising the recycling of organic residues at local scales and in contrasted peri-urban contexts of Northern and Southern countries is the general purpose of an international programme supported by the French National Research Agency (ANR). We present here the methodology and preliminary results to build up a structured set of tools to characterize the feedstock of organic residues and potential receiving crop-soil systems. They should serve for evaluating different practical scenarios of transformation and agricultural recycling of organic residues at the chosen scale.

(*) all “NF” and “X” standard methods are described in AFNOR (1999)

2- METHODS and GENERAL APPROACH

4- DEVELOPMENT OF ALTERNATIVE METHODS

0 5 10 15 20 25 30 35 0 1 2 3 4 5 6 7 Time (day) C m in e ra li z e d ( % )

Oxitop closed - pressure Oxitop opened - pressure Oxitop opened - NaOH Flask opened - NaOH

4.1- Kinetic of C mineralization using the Oxitop ® system

4.2- Organic residues characterisation from

Near Infra-Red Spectrometry

Figure 2. Relationships between the indicator of residual organic C in soil (IROC) issued from analyses (XPU 44-162-3; Lashermes et al, 2009) and predicted from NIRS (Peltre et al, 2009). Regressions lines for calibration and validation samples overlapped.

Figure 1. Carbon mineralization of Organic Residues: results obtained by the standard methods (flasks opened and C analyses in NaOH traps) and by recording pressure variations in Oxitop jars (various procedures) (S.E. means standard error)

REFERENCES: AFNOR 1999. Qualité des sols, AFNOR, Paris – Lashermes G, Nicolardot B, Parnaudeau V, Thuriès L, Chaussod R, Guillotin ML, Linères M, Mary B, Metzger L, Morvan T, Tricaud A, Vilette C, Houot S, 2009. Eur.J.Soil Sci. 60, 297-305 – Peltre C, Houot S, Barthès B, Brunet D, Thuriès L, 2009. NJF seminar: agricultural applications of NIRS and NIT, Stalgese (DK), 27-28 April 2009

ACKNOWLEDGEMENTS to ANR for its financial support, to D. Hadjar, M. Joly, V. Etievant, V. Mercier, JN. Rampon, K. Dhaouadi and C. Guillen for their help

4.3- Mapping C stocks with on field visible-IR Spectrometry and satellite imagery

5- CONCLUSION

3- STUDY SITES

Plaine de Versailles Dakar Mahajanga La Réunion

Examples of study sites and experiments : (1) Weighing organic residues (Dakar)

(2) Sampling organic residues used by farmers (Plaine de Versailles) (3) Experimental field upon organic residues application in market

gardening (Mahajanga) 3)

3) Table 1. List of biological physico-chemical tools for organic residues characterisation

Handling normal flasks

We used ASD FieldSpec PRO for field visible-NIR measurements. We obtained good correlations between spectra and soil organic C contents, with RMSEP of 4.1 g/kg.

Technique Measure

Our study focuses on four peri-urban agricultural areas : - Plaine de Versailles (40 km W from Paris, France) - Mahajanga (Madagascar)

- La Réunion (France, Indian Ocean) - Dakar (Sénégal)

The participants agreed on a list of relevant techniques and adjusted their procedures, generally by referring to international standards. The table illustrates the case of organic residues (OR) studies. Several methods may be adapted or replaced by alternative ones to fit subsequent steps of ISARD, i.e., survey of defined areas and assessment of positive and negative impacts of OR recycling in agriculture.

Optimized method with Oxitop devices compared to the standard one: same quantitative results, more accurate, less working time and cost, but applicable for relatively short incubations (Fig. 1)

1)

2)

• Studies of organic residues recycling in agriculture need a large number of consolidated analyses, which are also costly and time-consuming.

• The ISARD project selected techniques suitable to complete data sets and to supply integrated tools for evaluation of recycling scenarios in peri-urban areas.

• Alternative methods are proposed and developed, which should facilitate data collection and next decision-making tools.

S.E.

NIRS allow good predictions of C contents, after calibration, with less time and money than standard analyses (Fig. 2).

Using Oxitop devices

Soil samples

MODEL PLSR regression

Laboratory analyses

Spectres du terrain PVPA.

0,00 0,10 0,20 0,30 0,40 0,50 0,60 3004005006007008009001000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 λ (nm) R 04b2-2 07a1-2 04b2-2 07a1-2 re fl e c ta n c e field spectra SOC

ASD FieldSpec Pro