DNDC DeNitrification-DeComposition

Policy support tool

DNDC DeNitrification-DeComposition

DNDC is a computer simulation model of carbon and nitrogen biogeochemistry in agro-ecosystems. The model can be used for predicting crop growth, soil temperature and moisture, carbon dynamics, nitrogen leaching, and trace gases emissions.

The DNDC model can assess the soil matter turnover, which can indirectly indicate the state of degradation. It is a point-scale model and can be extrapolated to large spatial extents using remote sensing and GIS approaches.

Aim of the resource

The DNDC model was initially developed in the 1990s for quantifying carbon sequestration and emissions of nitrous oxide, nitrogen and carbon dioxide from agricultural soils in the USA. This was done by modeling coupled decomposition and denitrification processes to predict carbon and nitrogen turnover in agricultural soils. Since then the original DNDC model has been adapted to include different scenarios and ecosystems including forests, wetlands and rice paddies. According to Gilhespy et al.'s (2014) survey, 41% of survey respondents use DNDC-based models for estimating nitrous oxide emissions, whilst 54% of survey respondents use it for assessing the potential impacts of land use change.

Using the resource

Potential benefits from using the resource

According to Gilhespy et al. (2014) one strength of the DNDC model is that it is relatively easy to use and has an attractive user interface.

Another strength identified by Gilhespy et al. (2014) is that DNDC has a comprehensive library of default settings for 62 crops and 12 soil types, enabling users to model a wide range of sites and situations without inputting data.

The majority of output parameters are reported on a daily time step, offering users considerable flexibility not only in the situations modelled, but in the output available for evaluation.

Potential limitations from using the resource

There is a need for a more detailed instruction manual with a good descriptions of the processes behind DNDC and detailed explanations of the input and output parameters (Gilhespy et al., 2014).

Lack of field validation and uncertainty in model parameters are major barriers in their applicability to areas where local databases are very scarce

Scope

Sub/region where used

Caribbean

Central Africa

Central and Western Europe

Central Asia

East Africa and adjacent islands