Modelling organic matter dynamics in New Zealand soils.
To ensure the sustainability of land systems in terms of nutrient cycling and maintenance of soil physical conditions, there is a need to understand soil organic matter (SOM) and its dynamics. It has been suggested that soil-carbon (C) models developed internationally do not perform well under New Zealand's unique climatic and soil mineralogical conditions. To test this hypothesis, we conducted 14C-labelled ryegrass decomposition studies and assessed the influence of abiotic factors on decomposition rates. These factors were characterized by estimating system mean residence times (MRTs) from estimates of first-order rate coefficients in a simple, three-compartment model. A range of MRTs obtained for decomposition was related to climatic conditions and soil properties. We summarise this work and extend this study to apply the Rothamsted soil-C turnover model, a five-compartment model, to our data with the view of testing both the model projections and the decomposability factors assumed in the model.
Parshotam
A
A
Landcare Research, Palmerston North, New Zealand. parshotama@landcare.cri.nz
Saggar
S
S
Tate
K
K
Parfitt
R
R
D002250:Carbon Radioisotopes / Q000032:analysis / Q000378:metabolism; D017753:Ecosystem; D005544:Forecasting; D008129:Lolium / Q000378:metabolism; D008962:Models, Theoretical; D009930:Organic Chemicals / Q000378:metabolism*; D012987:Soil
D002250:Carbon Radioisotopes; D009930:Organic Chemicals; D012987:Soil