A5030256135- Soil Carbon and Nitrogen Dynamics
- Soil and Water Nutrient Dynamics
- Forest Management and Policy
- Soil Geostatistics and Mapping
- Heavy metals in environment
- Peatlands and Wetlands Ecology
- Hydrology and Watershed Management Studies
- Forest ecology and management
- Isotope Analysis in Ecology
- Soil and Unsaturated Flow
- Fire effects on ecosystems
- Clay minerals and soil interactions
- Soil erosion and sediment transport
- Gene Regulatory Network Analysis
- Environmental Impact and Sustainability
- Pacific and Southeast Asian Studies
- Chromium effects and bioremediation
- Agroforestry and silvopastoral systems
- Mine drainage and remediation techniques
- Plant Ecology and Soil Science
- Pesticide and Herbicide Environmental Studies
- Lignin and Wood Chemistry
- Parasite Biology and Host Interactions
- Fluid Dynamics and Mixing
- Microbial Community Ecology and Physiology
University of Waikato
2015-2018
National Institute of Water and Atmospheric Research
2008-2013
Manaaki Whenua – Landcare Research
1993-2006
Massey University
1991-2006
Crown Research Institutes
2002
Carbon storage and turnover times of total soil C (up to 1 m depth) topsoil (to 23 cm depth mineral soil) were compared at six sites in native tussock grasslands three old-growth forests New Zealand. Annual inputs the topsoils also determined. Most approached steady state, covered a wide range climoedaphic environments. Total ranged from 44 268 t ha1 depth), was highest Spodosol beneath mixed podocarp-hardwood forest. Turnover C, estimated radiocarbon content organic matter, mostly 30 125...
Total organic carbon (C) and natural 13C abundance were measured in adjacent allophanic soils (Andisols) non-allophanic (Inceptisols) under maize (Zea mays L.) ryegrass pasture (Lolium perenne to assess the C turnover rate of contrasting mineralogy specific surface area. The soil contained more total than (139 v. 101 t C/ha upper 0–35 cm) but neither showed a significant difference content between maize, provided residue was retained incorporated. gross annual inputs both estimated...
Since 1992, afforestation with Pinus radiata D. Don in New Zealand has led to the establishment of over 600 000 ha new plantation forests, about 85% which are on fertile pastures used previously for grazing sheep and cattle. While this leads rapid accumulation carbon (C) vegetation, effects soil C poorly understood. We examined key cycling processes at (former) Tikitere agroforestry experimental site near Rotorua, Zealand. In 1973, replicated stands P. (100 400 stems/ha) were established...
Land cover is a critical factor that influences, and influenced by, atmospheric chemistry potential climate changes. As considerable uncertainty exists about the effects of differences in land on below-ground carbon (C) storage, we have compared soil C contents turnover at adjacent, unmanaged, indigenous forest (Nothofagus solandri var. cliffortiodes) grassland (Chionochloa pallens) sites near timberline same climo-edaphic environment Craigieburn Forest Park, Canterbury, New Zealand. Total...
The soil solution chemistry of heavy metal amended soils is great importance in assessing the bioavailability metals and their toxicity to biota. Three contrasting were with Cd(II), Cu(II), Ni(II), Pb(II), Zn(II), Cr(III) nitrate salts at rates 10–100 mmol/kg. This concentration range was chosen encompass a wide effects on sensitive biochemical properties as part larger project. Soil solutions extracted analysed for pH, concentrations metals, major cations anions. Heavy speciation calculated...
The composition of the nematode assemblage in pasture plots that received sewage sludge amended with 4 rates Cu, Ni, or Zn was assessed 5 years; highest rate application each metal near New Zealand regulatory limit. activity heavy metals soil solution determined at sampling. In terms management, conditions 1999 and 2000 were most settled, while activities explained some 44% variance total nematodes, there few significant correlations between genera individual metals. Both Cu depressed...
Reduction of visual clarity in streams by diffuse sources fine sediment is a cause water quality impairment New Zealand and internationally. In this paper we introduce the concept load optical cross section (LOCS), which can be used for load-based management light-attenuating substances models that are based on mass accounting. approach, beam attenuation coefficient (units m–1) estimated from inverse m) measured with black disc. This also considered as an (OCS) per volume water, analogous to...