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Massey includes teams of researchers with skills relevant to the Centre in soil science, biochar production and integration into soil, and animal science.
Some clarification of the impacts of grassland intensification on food production, nitrogen release, greenhouse gas emissions and carbon sequestration: using the example of New Zealand
Anthony J. Parsons, John H. M. Thornley, Susanne Rasmussen and Jacqueline S. Rowarth, 2016, Some clarification of the impacts of grassland intensification on food production, nitrogen release, greenhouse gas emissions and carbon sequestration: using the example of New Zealand, CAB Reviews 2016 11, No. 054
We used an established, process-based model of the dynamics of carbon (C) and nitrogen (N) cycling between plants, soils and animals in grazed temperate pastures to clarify expectations of how some major components of intensification affect the outcomes (short-term and long-term) of alternative systems for food production and environmental impact. We use the example of New Zealand, due to its clear recent history of intensification, the level of concern and hence nature of research undertaken there. A transition from low-input drystock, to dairy (lactation) systems with higher N inputs in fertilizer, and/or C and N inputs in supplements, reveals how at the same intermediate N input, food yield (per ha) can be doubled, while environmental N release halved, with minimal impact on C sequestration. We stress the sources of sustained changes in N release (e.g. nitrate/ nitrous oxide) are altered inputs (fertilizer/supplements) and less so animal numbers in response to these. Much of the increased efficiency is due to ‘improved’ N partitioning in lactating (cf. dry) animals. A reversion to dry-stock (or ‘de-stocking’) therefore offers greater environmental challenge, unless N inputs decline accordingly. Responses to supplements (being a source of C) re-inforce how the driving limitation to the grazed ecosystem is C capture per ha, and we highlight the need for a renewed focus on fundamental research on plant C uptake per ha per unit of N input. We offer a graphical method for visualizing the outcomes of options, and their trade-offs, with implications for policy and future research direction.
Keywords: Intensification, Carbon sequestration, Nitrogen use efficiency, Supplements, Dairy production
Undergraduate Student: Martina Alvarez Camps
"My name is Martina Alvarez. I am 19 years old and about to start my second year of Chemical and Materials Engineering at the University of Auckland."
Martina spent the summer with Dr Carolyn Hedley and Dr Pierre Roudier at Landcare Research looking at the effect of moisture on soil spectra and the use of the External Parameter Orthogonalisation (EPO) algorithm to predict carbon content of field moist soil using air dry soil spectra models.
Martina's work has given her the opportunity to learn new skills and expertise in this field of soil science.
"I have learned about Visual-Near Infrared (VisNIR) spectroscopy and its benefits to soil science due to its quick soil carbon content predictions. I have also become aware of how samples are handled and scanned, the need for pre-processing of spectra and its application using the computer programming language R and how to accommodate the experiment to unexpected occurrences."