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Nicolas Puche

Doctor of Philosophy, (Soil Science)
Study Completed: 2017
College of Sciences


Thesis Title
Detailed temporal modelling of carbon and water fluxes from pastures in New Zealand: Case study of an experimental dairy farm in the Waikato region

Read article at Massey Research Online: MRO icon

Changes in soil carbon are difficult to measure directly because carbon amounts in the soil are highly variable. A new approach uses eddy covariance (ED) towers to measure the net emissions of carbon dioxide from soil. Mr Puche developed a detailed mechanistic ecosystem model that incorporated detailed representation of photosynthesis, transfers of energy, carbon and nutrients, and farm management practices. The model was designed to test the reliability of ED measurements, and better understand soil carbon behaviour under grazed dairy pastures in New Zealand. After parameterisation, the model achieved good performance that showed key biophysical drivers of the system were well modelled. His research identified systematic errors of considerable magnitude when ED measurements are confounded by carbon dioxide emissions from grazing animals near the measurement towers, leading to incorrect estimates of the farm’s carbon balance. Mr Puche's modelling allowed animal respiration to be subtracted from soil emissions, rectifying the error.

Professor Michael Hedley
Dr Miko Kirschbaum
Professor Louis Schipper
Professor Marta Camps Arbestain
Dr Michael Dodd

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