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Flux investigations for intensive dairy farming, Hamilton Basin, NZ. Dave Campbell, Louis Schipper, Paul Mudge & Tehani Kuske Earth and Ocean Sciences University of Waikato. Context: Changes in TC and TN within NZ pasture soils.
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Flux investigations for intensive dairy farming, Hamilton Basin, NZ Dave Campbell, Louis Schipper, Paul Mudge & Tehani Kuske Earth and Ocean Sciences University of Waikato
Context: Changes in TC and TN within NZ pasture soils • Soils collected from previously sampled sites (17-30 yrs ago) had been archived and were reanalysed for TC and TN Sites sampled to date
Change in Total C and Total N—initial 31 sites Top 1 m of soil profile: Total C loss was about 1 t ha-1 yr-1 Total N loss was about 90 kg ha-1 yr-1 Schipper L.A., Baisden W.T, Parfitt R., Ross C., Claydon J. (2007) Large losses of soil C and N from soil profiles in New Zealand during the past 20 years. Global Change Biology, 13: 1138-1144
Ongoing sampling • Need more data to confirm landuse/land-form findings • Resampling of previously sampled profiles • What, where, when? • Hill country around Palmerston North • South Island – Pallic and Semi arid soils • Dairy and drystock • Tussock (native grasslands)
Research needs • Quantitative measurements of carbon exchange in relation to different farming practices—applications for EC • e.g. To what extent do the following practices decrease soil C? • pasture renewal • pugging/poaching • irrigation • fertiliser • feed crop production • etc…
Torehape peat mine 2005–06 Opuatia wetland 2003–05 Rukuhia (dairy) 2002–03 Moanatuatua wetland 1999–2000 Previous work Scott Farm (dairy) 2007– Landcare Research
Carbon budget for dairy farming on peat soils 2002-3 C budget Nieveen et al. 2005, GCB 11: 607–618
Scott Farm site • Dairy industry research farm (Dairy NZ) • Focus on increased production vs environmental costs • Soils: mod. well drained silt loam • Landuse: dairy cow grazing + cut & carry harvesting • Research capability (from Dec. 2007): • Open path EC (CSAT3 + LI7500 + CR3000) • Soil CO2flux chamber (LI8100)
Hukseflux NR01 REBS Q7
Scott Farm immediate research objectives • Annual CO2–C budget under typical NZ dairy grazing management • 3-4 cows/ha (rel. high land pressure) • Models of annual water use • Case studies of farm management practices: effects on CO2 fluxes • Cultivation/pasture renewal • Overgrazing/pugging (winter) • Long-term: • Simple models of farm soil carbon stocks & changes
Scott Farm: Initial results Midday CO2 fluxes
Thanks…… • DairyNZ and Scott Research Farm staff