The NZAGRC’s former nitrous oxide and soil carbon work streams were combined into one programme this year. This ensures a strong overall framework, closer communication and full GHG analyses across the programme. The programme focusses on three key areas:
1. Identifying and prioritising plant traits for low GHG emissions;
2. Mitigation practices to maintain soil carbon and reduce nitrous oxide emissions at paddock scale; and
3. Defining the achievable soil carbon stabilisation capacity of New Zealand grassland soils.
Current progress and research stories
The carbon balance of temperate grasslands part II: The impact of pasture renewal via direct drilling
S. Rutledge, A.M. Wall, P.L. Mudge, B. Troughton, D.I. Campbell, J. Pronger, C. Joshi, L.A. Schipper, The carbon balance of temperate grasslands part II: The impact of pasture renewal via direct drilling, Agriculture, Ecosystems & Environment, Volume 239, 2017, Pages 132-142, ISSN 0167-8809, http://dx.doi.org/10.1016/j.agee.2017.01.013
Two blocks had pastures renewed (PR) by direct drill. A third block was a control.
The PR blocks had smaller positive NEPs than the control block during the PR year.
Duration of fallow is important in determining total CO2 losses due to PR
Pasture renewal led to a negative carbon balance (soil C loss) for the PR year
Addition of C (e.g. manure, effluent, feed) helps to mitigate soil C loss due to PR.