Nutrients/Data uncertainties limitations: Difference between revisions

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{{ComponentDataUncertaintyAndLimitationsTemplate
{{ComponentDataUncertaintyAndLimitationsTemplate
|Reference=Bouwman et al., 2009; OECD, 2012; FAO, 2012; Beusen et al., 2008;
|Reference=Bouwman et al., 2009; OECD, 2012; FAO, 2012; Beusen et al., 2008;
|Description=<h2>Data,  uncertainties and limitations</h2>
|Description=<h2>Data,  uncertainties and limitations</h2>
The data used in this chapter stem from various parts of IMAGE, such as those on land cover, biomes, crop production and allocation, livestock, fertiliser use and nutrient excretion rates;  environmental data include those on temperature and precipitation, runoff, and soil properties. External data are used for determining historical N excretion rates, manure spreading and fertiliser use efficiency, whereas their development in the future is a scenario assumption. Additional information only used in this chapter includes lithology, relief and slope of the terrain. The uncertainty of the model parameters are discussed in the various chapters of this book. Additional data used in the nutrient budget model include subnational data as used for the United States and China.
===Data===
Regarding uncertainties, the budget calculations and individual input terms for the year 2000 were found to be in good agreement ([[Bouwman et al., 2009]]) with detailed country estimates for the member countries of the Organisation for Economic Co-operation and Development ([[OECD]]) ([[OECD, 2012]]). However, it is clear that the uncertainty in some of the budget terms is larger than for others. Data on fertiliser use are more reliable than on N and P animal excretions, which is calculated from livestock data ([[FAO, 2012]]) and excretion rates by animal category. Data on crop nutrient withdrawal are less certain than on crop production, because the withdrawal is calculated with fixed global nutrient contents of the harvested shares of marketed crops. Apart from the uncertainty in nutrient contents, major uncertainties arise from lack of data; data on crops that are not marketed and the use of crop residues are not available, and this causes major uncertainties about nutrient withdrawal.
The data stem from various parts of IMAGE, such as land cover, biomes, crop production and allocation, livestock, fertiliser use and nutrient excretion rates. Environmental data include temperature and precipitation, runoff, and soil properties.  
Sensitivity analysis ([[Beusen et al., 2008]]) showed that the most important determinants of the uncertainty of the nutrient model comprise:
 
# N excretion rates
External data are used for determining historical N excretion rates, manure spreading and fertiliser use efficiency, and their development in the future is a scenario assumption. Additional information used only in this chapter includes lithology, relief and slope of the terrain. Additional data used in the nutrient budget model include subnational data as used for the United States and China.  
# NH3 emission rates from manure in animal housing and storage systems,
# the fraction of the time that ruminants graze
# the fraction of non-agricultural use of manure) specific to mixed and industrial systems
# animal stocks.


===Uncertainties===
With regard to uncertainties, the budget calculations and individual input terms for 2000 have been found to be in close agreement ([[Bouwman et al., 2009]]) with detailed country estimates for the member countries of the Organisation for Economic Co-operation and Development ([[OECD]]) ([[OECD, 2012]]).


However, uncertainty is larger for some of the budget terms than for others. Data on fertiliser use are more reliable than on N and P animal excretions, which are calculated from livestock data ([[FAO, 2012]]) and excretion rates per animal category. Data on crop nutrient withdrawal are less certain than on crop production, because the withdrawal is calculated with fixed global nutrient contents of the harvested proportions of marketed crops. In addition to uncertainty in nutrient contents, major uncertainties arise from insufficient data, for instance, on crops that are not marketed and on the use of crop residues. This leads to major uncertainties about nutrient withdrawal.
Sensitivity analysis ([[Beusen et al., 2008]]) has shown that the main determinants of the uncertainty in the nutrient model are:
#N excretion rates; 
#NH3 emission rates from manure in animal housing and storage systems; 
#the proportion of time that ruminants graze, the proportion of non-agricultural use of manure in mixed and industrial systems;
#animal stocks.
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Revision as of 11:36, 12 February 2014

link to framework components overview

Parts of Nutrients/Data uncertainties limitations

  1. Introduction page
  2. Model description
  3. Policy issues
  4. Data, uncertainty and limitations
  5. Overview of references
Component is implemented in:
Components:
Related IMAGE components
Projects/Applications
Key publications
References
Nutrient module of IMAGE 3.0
Flowchart Nutrients. See also the Input/Output Table on the introduction page.
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