We are collaborating with Plant & Food Research, AgResearch, the University of Waikato, the University of Auckland, and Auckland University of Technology to better understand soil health and resilience. In the field we have sampled and are analysing more than 150 different soil profiles (many down to more than 60 cm deep) from land use comparisons and long-term experiments. We are investigating how land use affects changes in soil carbon and soil chemistry and how those in turn affect other soil properties such as soil aggregation and microbial activity.
Long term experiments
We are utilising (the few) long-term experiments in New Zealand that represent controlled trials (including the Winchmore fertiliser and irrigation trials).
Irrigated versus non-irrigated sites
We have sampled irrigated versus non-irrigated Otago sites on semi-arid soils that have been flood irrigated for 80 to more than 100 years. Because these soils formed under more arid conditions, they are suspected to be more susceptible to changes under irrigation than soils formed where precipitation is greater.
Pasture compared with cropping sites
In collaboration with the S-map Next generation Endeavour funded project, we are researching how changes in soil carbon and other properties including a soil’s physical condition affects soil hydrology and soil function. Approximately 90 sites in Canterbury (dryland sheep and beef, cropping and irrigated dairy) on three different soil types have been sampled and are currently being analysed for a variety of soil properties. Recent work undertaken in the Waikato region has compared maize and pasture on 42 paired sites (84 sites total) on a range of soil orders, e.g. Allophanic, Gley, Granular, and Ultic soils.
Cropping and Horticulture
Soil samples from maize cropping, kiwifruit and pasture sites are being compared to determine what controls biological functioning of these soils.