Carbon Conference Dubbo October 2010 Use of Biofertilisers to reduce carbon footprint in crop production and increase soil carbon levels

Outline of talk 1.Microbial biofertilisers can enable high crop yields with reduced N fertiliser application 2.Carbon footprint of N fertilisers 3.Examples of reduced carbon footprint via XXXX biofertiliser 4.Effects of N fertilisers on soil carbon levels 5.Effects of biofertiliser use on carbon sequestration 6.Carbon footprint audit and carbon offsets

Microbial biofertilisers can enable high crop yields with reduced N fertiliser application How? 1.If correct species are used N 2 is fixed from the atmosphere for use in the crop 2.Improved root growth 3.Improved soil health – develop a vigorous soil microflora N 2 + 8H + + 8e- 2NH 3 + H 2 = a steady supply of nitrogen for crop

XXXX produces larger root systems due to auxin synthesis (IAA) Greatly increased root hair density gives better nutrient capture Improved capture of any applied N (increased nitrogen use efficiency is an important mechanism of XXXX in crops)

Carbon footprint of N fertilisers Source: International Fertiliser Society Conference, Proceedings 639, 2008

Total CO2 eq per kg of N supplied = 9.3 kg CO2 eq for ammonium nitrate Source: Yarra International publication, 2010 Total CO2 eq per kg of N supplied for urea (production and field use) European average kg CO2 eq Potential with full BAT kg CO2 eq Source: International Fertiliser Society Conference, Proceedings 639, 2008

Sugarcane – Maryborough – QLD - Australia - BSES trial – Cane yield TC/ha TreatmentTC/ha 75N+1 XXXX82.0A 150N81.9A 75N+2 XXXX73.8A 33N+2 XXXX58.9 B LSD p0.01=12.8 Sugar yield TS/ha TreatmentTS/ha 75N+1XXXX13.6A 150N13.4A 75N+2 XXXX12.5A 33N+2 XXXX9.9 B LSD p0.01=2.3 Carbon footprint from N fertiliser Kg CO2 eq/ haKg CO2 eq/T yield Conclusion Use of XXXX enabled large reductions in urea application and this reduced the carbon footprint substantially

Effects of N fertilisers on soil carbon levels Summary In low fertility situations low to moderate application of N fertiliser can increase soil C In soils with normal fertility and C levels long term or excessive use of N fertilisers will reduce soil C levels

The Morrow plots – a landmark study of effects of long term N fertiliser effects on soil organic matter Source: Khan et al. (2007) J. Env. Qual. 36: 1821 – The myth of nitrogen fertilisation for soil carbon sequestration

Effects of biofertiliser use on carbon sequestration Reduce N fertiliser effects on soil C Increased microbial mass in soil increases soil C Increased root mass is an important mechanism for increasing soil C

Canola (OSR) trial, UK 2009 kgN/haYieldKg CO2 eq/T yield XXXX Renewable Fuels Agency's Carbon Calculator.

Quantifying carbon footprints for products and buying offsets MAB contracted Carbon Associates to do a C footprint audit. In June 2010 MAB purchased and surrendered 100 Tonnes CO2-e through the New South Wales GREENHOUSE GAS REDUCTION SCHEME (GGAS) XXXX

Conclusions Biofertilisers can enable reduced rates of nitrogen fertilisers and this reduces their tendency to reduce soil carbon Reduced nitrogen fertiliser applications equates to reduced carbon footprint per unit yield Biofertilisers can also contribute directly to increases in soil carbon sequestration

Thank you Contact Rob Bower