Soil Carbon and Emission Trading Scheme Mike Beare NZIAHS Forum (22 Aug. 2012)

The New Zealand Institute for Plant & Food Research Limited Why do we have an Emission Trading Scheme?  Under the Kyoto Protocol, NZ agreed to reduce its GHG emissions back to 1990 levels by 2012 or pay for any excess.  Government chose the ETS as least-cost way of putting a price on emissions and creating an incentive for all of us – especially businesses and consumers – to change behavior.  ETS moves the cost of emissions onto those who cause them. Creates a market around reducing emissions.  28 other countries have an ETS (incl. Australian & US states).  Creates incentive to reduce emissions, invest in clean technology and renewable power generation and store C (e.g. planting trees).  ETS was reviewed in 2011 to assess how it is working and what our trading partners are doing about climate change.

The New Zealand Institute for Plant & Food Research Limited What is included under ETS and When?  What sectors are included under the ETS Forestry – entered Jan 2008 Energy, Industry & Transport – entered July 2010 Agriculture – soon!  Proposed obligations under Agriculture participants initially meat & dairy processors, fertiliser manufacturers & importers, egg producers & live animal exporters. obligation to surrender NZUs for agricultural emission activities. Govt may move point of obligation to farm level in future, subject to practical issues, ability to verify emissions & enforce compliance. Agriculture emissions refers to non-CO 2 GHG emissions from agricultural production – includes CH 4 from livestock (~ 2/3), and N 2 O from animal excreta and use of N fertiliser (~ 1/3). Excludes soil C. Reporting was to begin Jan 2012, full obligations by Jan Recently, Govt deferred the start date to surrender obligations for biological emissions from agriculture – pending a review in 2015.

The New Zealand Institute for Plant & Food Research Limited CH Agric. emissions CH 4 = 6.3 Mt CO 2 -C e N 2 O = 2.7 Mt CO 2 -C e NZ Soil C stock = 2562 Mt C What are the losses and gains? How do they impact on NZ’s net emissions?

z Where do soils feature in the Global C Cycle ? Carbon (C) units: 1 t C = 1 Mg C 1 Gg C = 1000 t C 1 Mt C = 1000 Gg C 1 Pg C = 1000 Mt C

The New Zealand Institute for Plant & Food Research Limited Why are we interested in Soil C?  Soil C – product of organic matter input from plants and animal excreta and organic matter decomposition.  These have important implications for the global C balance.  Agricultural soil C is not currently included in the ETS but is included in international GHG accounting protocols.  Global basis – total soil C pool is large (small changes could be important).  There is growing international interest in soil C as a source and sink for atmospheric CO 2.  We don’t know how (i.e. point of obligation) or if soil C will be traded in the future and when.  Soil C is also linked to many important ecosystem services.  Supply of plant available nutrients, filtering, soil structure, biodiversity.

The New Zealand Institute for Plant & Food Research Limited How do we measure Soil Carbon? Important considerations Sample depth »Chemical fertility testing (0-15 cm samples), not adequate for soil C »Sampling to a fixed depth and known volume is essential »International C accounting/trading based on 0–30 cm »NZ data based on different depths of sampling, different protocols »Need for a standard, universally accepted protocol for NZ Number of samples »SOM and C can be very spatially variable »Large number of samples required (15-25 for avg paddock) »Composite sample OK, but separate samples better Corrections for soil bulk density are important Comparing C in equivalent masses of soil is best

The New Zealand Institute for Plant & Food Research Limited What is equivalent mass and why is it important?

The New Zealand Institute for Plant & Food Research Limited What are implications of different methods? Soil C content based 0-15 cm samples PastureCropping (ploughed 20 cm) Depth (cm) BD g / cm 3 C (%) t C / ha BD g / cm 3 C (%) t C / ha Total (Avg)(2.8)52.2(2.1)36.3 C Loss-15.9

The New Zealand Institute for Plant & Food Research Limited Determining the C content of soils (based on 0-25 cm samples) PastureCropping (ploughed 20 cm) Depth (cm) BD g / cm 3 C (%) t C / ha BD g / cm 3 C (%) t C / ha Total (Avg)(2.3)76.5(2.1)71.4 C Loss- 5.1

The New Zealand Institute for Plant & Food Research Limited Determining the C content of soils (based on equivalent soil mass) PastureCropping (ploughed 20 cm) Depth (cm) BD g / cm 3 C (%) t C / ha BD g / cm 3 C (%) t C / ha Total Equiv. mass C loss- 1.8 Values in red are t soil / ha (i.e. the mass of soil at each depth)

The New Zealand Institute for Plant & Food Research Limited Soil C stocks differ across land uses Jones et al. 2012

The New Zealand Institute for Plant & Food Research Limited Soil C stocks differ across major soil orders Jones et al. 2012

The New Zealand Institute for Plant & Food Research Limited NZ’s total soil C stocks by land use and change in soil C stocks due to land use change ( ) Source: NZ Greenhouse Gas Inventory (Ministry for the Environment) Excludes data for wetlands, settlements and “other” land. Land useLand area (ha) Soil C stocks (Mt C) ∆ soil C (Mt C) Forest Natural forest8,084, Pre-1990 planted forest1,441, Post-1989 forest593, Grassland High producing5,795, Low producing7,674, With woody material1,134, Cropland Annual334, Perennial102,

The New Zealand Institute for Plant & Food Research Limited Soils respond differently to changes in land use or management Lawrence-Smith et al 2006

The New Zealand Institute for Plant & Food Research Limited Are we losing or gaining soil C on our pastoral lands? Land formLand use0-30 cm0-90 cm nAvg. ∆Cn FlatlandDrystock (0.15) (0.27) FlatlandDairy (0.16) (0.25) NI hillDrystock (0.18) (0.37) SI tussockDrystock (0.13) (0.08) Change in total soil C (t C ha -1 yr -1 ) under different pastoral land uses Schipper et al Losses of soil C are also associated with release of mineral N that contributes to higher N 2 O emission under international accounting rules. Lawrence-Smith & Beare 2012

The New Zealand Institute for Plant & Food Research Limited Soil Carbon Sequestration Black/Biochar C Biomass pyrolysis Soil amendments Black/Biochar C Biomass pyrolysis Soil amendments Deep Placement Deep roots Bioturbation Recalcitrant compounds Deep Placement Deep roots Bioturbation Recalcitrant compounds Lifting Prod’n on Degraded Soils INM Irrigation ? Increase crop cover (min fallow) Lifting Prod’n on Degraded Soils INM Irrigation ? Increase crop cover (min fallow) Increasing C Input into Soil Residue mgt & reduced tillage Drip sub irrigation N management Biosolids Increasing C Input into Soil Residue mgt & reduced tillage Drip sub irrigation N management Biosolids Lal & Follett 2009 SSSAJ Spec Publication 57 Opportunities to sequester (store) soil C and reduce losses NZAGRC Research to increase soil C storage: stocks & upper limits of soil C storage mechanisms of soil C stabilisation. use of Biochar to sequester C introduce deep burrowing earthworms to bury soil C mixed pasture swards with deep rooted species Other Research Rates of soil C loss under LUC Reduced tillage systems to conserve soil C (cropping & pasture renewal) Irrigation effects on soil C stocks Measurement and modelling of functional pools

The New Zealand Institute for Plant & Food Research Limited CHALLENGES TO SOC SEQUESTRATION Competing uses of biomass Competing uses of biomass Fodder Fuel Industrial material Construction material Human dimensions Human dimensions Land tenure Mindset Gender issues Farming system Immediate vs. long-term needs Non-availability of input Non-availability of input Specific mechanisms Herbicides Fertilisers Improved varieties Weak institutions Soil factors Texture Clay minerals Drainage Topography Climate parameters Climate parameters Temperature Precipitation ET Rainfall distribution Pedosphere/ atmosphere interaction Pedosphere/ atmosphere interaction The Human Dimension Biophysical Factors Lal & Follett 2009 SSSAJ Spec Publication 57

The New Zealand Institute for Plant & Food Research Limited Ecosystem Services & Soil Organic Carbon Sequestration Erosion Control Reduction in nonpoint source pollution Decline in sedimentation Erosion Control Reduction in nonpoint source pollution Decline in sedimentation Desertification Control Decline in susceptibility to desertification Land saving technologies Desertification Control Decline in susceptibility to desertification Land saving technologies Increase in Biodiversity Soil fauna and flora Avoiding deforestation Increase in Biodiversity Soil fauna and flora Avoiding deforestation Purification of Water Bioremediation Denaturing of pollutants Purification of Water Bioremediation Denaturing of pollutants improvement in soil structure storehouse of germplasm soil as a biomembrane Soil/ecosystem restoration Lal & Follett 2009 … and there are many other benefits of soil C

The New Zealand Institute for Plant & Food Research Limited Conclusions  NZ Soil C stock is relatively large compared to annual emissions of CH 4 and N 2 O from agriculture.  Annual changes in soil C appear small, but what are implications of changes in land uses?  Are we losing or gaining soil C from intensification of existing land uses?  How we measure soil C stocks and changes is important (Paddock & Nationally)  Soil C stocks differ substantially by land use, soil class and climate  Potential to increase soil C storage appears to be small (more research needed)  Given our stocks of C are high, risk of soil C losses is biggest concern. Pastoral land and selected soils (e.g. peats, Allophanics etc)  Beyond soil C accounting, important that we account for the full range of ecosystem services provided by soil C.

Thank you for your attention