Techniques for measurement of GHG emissions:

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1 Techniques for measurement of GHG emissions: In situ soil and biomass sampling for carbon and nitrogen measurements Peter Koncz MTA-SZIE Plant Ecology Research Group Livestock and Climate Change Training, 29 th October 2014, Gödöllő, Hungary

2 Biomass and soil is a large sink, source and storage of greenhouse gases Around 40-42% of the forage, hay (dry mass) is CARBON and 2-3% is NITROGEN! Grassland management (grazing, mowing, crop production) should increase carbon sequestration soil carbon and nitrogen content livestock supporting capacity How do we know how large are these?

3 Estimation of carbon and nitrogen content of biomass and soil Direct measurements Biomass sampling Above and below ground Soil sampling Indirect measurements Leaf area index Vegetation indexes Flux measurements Chamber techniques Eddy covarience Remote sensing

4 Biomass sampling Above ground biomass cutting From 1 ha at least 5 sample in a 0.5*0.5 meters quadrate Drying (65-85 C for 48 hours, depends on sample, to constant weight)

5 50cm Measurement design (exercises for today) Short grass quadrates 50cm Tall grass quadrates Biomass sampling Soil sampling Leaf are index Vegetation indexes Flux measurements Soil respiration Phtosynthesis NEE N2O H2O

6 Soil sampling Below ground biomass, soil carbon and nitrogen content Soil is sieved (<2 mm Ø), washed to separate roots from the soil Oven-dried at C for 48 h (depends on sample) to constant weight

7 Soil sampling design

8 Soil carbon and nitrogen determination Soil carbon (organic, inorgnic) and nitrogen content is usually determined with dry combustion method E.g. with LECO CN elemental analyzer; furnace at 1350 o C in pure oxygen>co 2 evolve.

9 Soil stocks (soil carbon density, SCD) calculation where SOC content is a soil organic carbon content, % of mass (kgc/kg soil x 100) BulkDensity is a soil bulk density, (kg soil/dm3) Depth is a thickness of the sampled layer, dm; frag is volume of coarse fragments, % of mass or (m3 stone/m3 soil)

10 Soil organic carbon change (ΔSOC) calculation where: SOC ref is reference SOC; SOC new is a new (determined during subsequent field campaign) SOC stock; f org is C with organic fertilizers (if applied); f lim is C with lime (if applied).

11 Biomass Productivity Grazed grass Mowed hay Harvest index Carbon input Carbon stock g C m -2 g N m -2

12 Biomass (g m -2 ) Leaf area index (LAI) LAI is the one-sided leaf area per unit ground surface area (m2 / m2). We estimate it from the ratio of light intesity above and below canopy Biomass vs LAI ( ) y = 95x R² = LAI

13 Biomass (g m-2) Vegetation index VIGreen index is a vegetation index among many others (e.g. NDVI) which represents the vegetation cover over a surface. It is derived from RGB digital photos. VIGreen index is the normalized difference of reflected green and red: VIGreen vs. biomass ( ) VIGreen y = 1222x R² = 0.39

14 N 2 O, CH 4 sampling Static chamber method Air samples (syringe, 0, 10, 20 min) Concentration changes determined with a gas chromatograph

15 N 2 O flux calculation where F N2O is the flux (μg N m 2 hour 1), ΔC is the difference in mixing ratios (pbb) in chambers at the end and start of samplings, t is the sampling time (h), AN is the atomic weight of nitrogen (N), Vch is the volume of chambers (m3), f is the correction factor taking into account the residual pressure in the evacuated tubes, Vm is the molar volume of air (m3), Ach is the surface area (m2) of soil covered by chambers.