Maria Luz Cayuela

Murcia. SPAINCEBAS-CSICCEBAS-CSIC

Centro de Edafología y Biología Aplicada Centro de Edafología y Biología Aplicada del Seguradel Segura

Council of Scientific ResearchCouncil of Scientific Research

http://www.cebas.csic.es/ingles/index_ingles.html

DEPARTMENT OF SOIL AND WATER CONSERVATION DEPARTMENT OF SOIL AND WATER CONSERVATION AND ORGANIC WASTE MANAGEMENTAND ORGANIC WASTE MANAGEMENT

GROUP OF SOIL ENZYMOLOGY, BIOREMEDIATION AND ORGANIC WASTES

Main research interests:• Development of strategies for improving the knowledge

on the mechanisms conducting the processes of soil degradation and rehabilitation, and particularly those of C cycle.

• Obtaining sensitive bioindicators of biological soil quality and functionality, based on its microbial activity, biochemistry (enzymology), and biodiversity.

• Recycling in soil of organic amendments and their effect on C sequestration

• Composting of organic wastes for agricultural use

Research linesComposting: •Pilot and industrial scale•Set up the best management practices: best mixtures, aeration system, turning frequency etc…•Evolution of physico-chemical and biochemical properties: maturity and stability

Compost application: •Field study•Effect on soil quality: TOC, CEC•Effect on crop: foliar analysis and olive yield.•C sequestration

Temporary strategy to tackle GHG emissions• Affected by climate, land use, type of soil,

exogenous organic matter characteristics, etc

Win-win strategy

Increas ing interest on soil C sequestration

Mediterranean soils: Potential to lock C• Low OM concentration• Degraded soils

Understanding mechanisms involved in C cycle• Mitigation options

Processes that control soil C storage and GHG emissions• Implications in soil C sequestration potential• Study of variables such as

o Exogenous organic matter mineralisation rateo Composition of added organic mattero Effect of type of soil,...

Application of organic residues to soil: implications on GHG emissions and C

sequestrationIstituto Sperimentale per la Nutrizione delle Piante.ISNP-CRA, Gorizia. ITALY

How to measure CO2 flux?

Micrometeorological technique: Eddy covariance• Main methodology for measuring CO2 exchange

between terrestrial ecosystems and the atmosphere at field scale.

• Chamber methods to measure CO2 and other trace gases (CH4, N2O)• Most commonly used method to measure the

exchange of trace gases.• Suited for both laboratory and field scale

experiments.

Closed s tatic chambers

• Efflux calculated from the rate of changing of CO2 concentration in a closed volume.

removablechamber

samplingport

fixedcollar

Soil

CO2

• CO2 concentration measured by IR, soda trap. The use of GC allows to measure other trace gases

Soil

CO2CO2

CO2

CO2

t0 = 0 t ≈ 20 – 60 minutes

Closed dynamic chambers

Air in the chamber is circulate through a detector.

• Efflux calculated from the rate of changing of CO2 concentration in a closed volume.

• Type of detector: Usually IRGA or GC (other gases)

t0 = 0 t ≈ 20 – 60 minutes

Soil

CO2 CO2 CO2

CO2

Pump Detector

SoilCO2

Pump Detector

Advantages/disavdantages of closed chambers

• Advantages• Measure very small fluxes.• Cheap and easy to set up• Allows automation.

Disadvantages• Influence on natural soil fluxes.• Can affect gas concentration profiles within the

soil (gas accumulation), even in the case of closed dynamic chambers

• Air-filled pore space below the chamber accounts as chamber volume.

• Do not represent real conditions

Description of the incubation system

Chamber method adapted to measure soil trace gas fluxes (CO2, N2O and CH4) under laboratory scale

inlet

outlet

Description of the incubation system

multipositionvalve

multipositionvalve

airpump

outlet

16 open flasks containing the amended soils and aerated by means of a air pump

Description of the incubation system

airpump

outlet

at regular intervals (every 20 min) one flask is converted into a closed dynamic system by means of a valve system

peristalticpump

Selectedstream outlet

Selectedstream outlet

Description of the incubation system

airpump

microGC gas concentration in the flask is measured at

two different time intervals by GC

peristalticpump

outlet

Description of the incubation system

Example

C mineralisation dynamics in amended soils under laboratory conditions.

Variable studied:

- type of soil

Pérdidas de Materia OrgánicaMaterial description

Soil amendment: Commercial meat bone meal (MBM)43.1 %C; 9.4 %N; 18.6%fat; dose: 200 kgN Ha-1

Incubation conditions:20ºC, 14 days, soil CO2 flux measured every 3 hours

Soil characteristics:Management Sand Silt Clay pH CaCO3 NTOTCORG BC

(H2O) µg g-1

I Arable 69 28 3 8.3 74.0 0.57 0.05 114II Arable 52 21 27 8.0 41.5 1.04 0.10 119III Grassland 37 48 15 7.8 4.6 2.54 0.24 795IV Arable 6 48 46 7.0 -- 3.20 0.45 269V Grassland 67 21 12 6.7 -- 2.20 0.21 205VI Arable 55 28 17 5.0 -- 0.87 0.12 118VII Arable 54 32 14 4.6 -- 0.81 0.13 65

% %

8.38.07.87.06.75.04.6

Pérdidas de Materia OrgánicaCO2 evolution during soil incubation

Typical respiration rate of a commercial meat bone meal(200 kg N Ha-1) in two different agricultural soils at 20 ºC.

0

5

10

0 3 6 9

time (days)

CO2 -C

evo

lution

(µg

kg m

in-1

) I+MBMII+MBMIII

High sampling frequency

Low coefficientof variation

Pérdidas de Materia OrgánicaCO2 evolution during soil incubation

time (days)

Cum

ulat

ive

extra

CO

2-C

(µg·

g-1)

0

20

40

60

80

3 6 9 12

S.Martino Gorizia

Bueris

Lodi

Reana

Ribis

Jumilla

Cumulative extra CO2-C evolved during the decomposition of commercial meat bone meal (200 kg N Ha-1) in seven

different agricultural soils at 20 ºC.

30.3 %of added C

11.5 %of added C

IIIIIIIVVVIVII

Correlation to soil phys icochemical properties

Fitting to mineralisation kinetic models

time (t)

Cum

ulat

ive

extra

CO

2-C(t) Cmax

t1/2

/2Cmax

( )kttC

2/11

max

+=CO2 –C(t)

Sigmoidal growth modelSigmoidal growth model

• No simple linear correlation

• Multivariable linear regression for t1/2 and soil pH (+), texture (-, sand) and BC (-)• R2=0.97; P<0.01

Discuss ion

• Soil pH directly correlated to t1/2

Regulates adsortion of proteins to mineral surfacesElectrostacic chargesFunctional groups

• Soil texture inversely correlated to t1/2

Physical protection of organic matter with clays Strong links between proteins and clays

• Microbial biomass inversely correlated to t1/2

Main responsible for degradation

Conclus ions

• The proposed semiautomatic chromatographic method succeded in the identification of soil pH, texture and microbial biomass as variables affecting MBM mineralisation

• There is a large number of variables affecting C mineralisation in amended soils that need to be tested under controlled conditions

• Laboratory scale experiments represent a powerful tool to asses the effect of different variables on C cycle before the setup of field scale experiments

International collaborations:

Prof. H. Insam. University of Innsbruck (Austria).

Prof. E. Stentiford. University of Leeds (United Kingdom).

Prof. Maria de Nobili. University of Udine (Italy).

Prof. P. Brookes. Rothamsted Research (UK).

Dr. P.D. Millner. United States Department of Agriculture (USA).

Dr. J.W. van Groenigen. Wageningen University (The Netherlands).

Recent publications on composting:•Cayuela, M.L., Bernal, M.P., Roig, A. 2004.Composting olive mill waste and sheep manure for Orchard Use. Compost Science & Utilization. 12(2): 130-136.

•Cayuela, M.L., Sánchez-Monedero, M.A., Roig, A. 2006.Evaluation of two different aeration systems for composting two-phase olive mill wastes.Process Biochemistry. 41: 616-623.

•Cayuela, M.L., Millner, P.D., Slovin, J., Roig, A. 2007.Duckweed (Lemna gibba) growth inhibition bioassay for evaluating the toxicity of olive mill wastes before and during composting. Chemosphere 68: 1985-1991.

•Cayuela, M.L., Mondini, C. Sanchez-Monedero, M.A. Roig, A. 2007.Chemical properties and hydrolytic enzyme activities for the characterisation of two-phase olive mill waste composting. Bioresource Technology, doi:10.1016/j.biortech.2007.08.057.

Soil application: C and N mineralization, fertility, C sequestration, GHG emissions•Mondini, C., Cayuela, M.L., Sánchez-Monedero, M.A., Roig, A., Brookes, P.C. 2006. Soil microbial biomass activation by trace amounts of readily available substrate. Biology and Fertility of Soils. 42: 542-549.

•Cayuela, M.L., Sinicco, T., Fornasier, F., Sanchez-Monedero, M.A., Mondini, C. 2007.Carbon mineralization dynamics in soils amended with meat meals under laboratory conditions.Waste Management, doi:10.106/j.wasman.2007.09.028.

•Mondini, C., Cayuela, M.L., Roig, A., Sinicco, T., Cordaro, F., Sánchez-Monedero, M.A. 2007.Greenhouse gas emissions and C sink capacity of amended soils under laboratory conditions. Soil Biology & Biochemistry 39: 1366-1374.

Soil application: C and N mineralization, fertility, C sequestration, GHG emissions•Mondini, C., Cayuela, M.L., Sinicco, T., Sanchez-Monedero, M.A, .Bertolone, E., Bardi, L. 2007.Soil application of meat and bone meal. Short-term effects on mineralization dynamics and soil biochemical and microbiological properties.Soil Biology and Biochemistry, doi:10.1016/j.soilbio.2007.09.010.

•Sanchez-Monedero, M.A., Cayuela, M.L., Mondini, C., Serramia, N., Roig, A. 2007.Potential of olive mill wastes for soil C sequestration. Waste Management, doi:10.106/j.wasman.2007.09.029

•Brookes, P., Cayuela, M.L., Contin, M., De Nobili, M., Kemmitt, S., Mondini, C. 2007.The mineralisation of fresh and humified soil organic matter by the soil microbial biomass. Waste Management doi:10.106/j.wasman.2007.09.015.