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Pasture Module (31_pasture)

Description

The Pasture Module defines land used as pasture for livestock rearing. At the same time, it calculates the corresponding carbon content of the resulting pasture land. Therefore, the module requires cellular information about the carbon density stored in natural vegetation carbon pools. Furthermore, it delivers regional production costs associated with pastures. Geographically explicit production of pasture biomass in accordance to available pasture area is generated as output.
h2. Interfaces

Input

Name Description Unit A B
$vm\_carbon\_stock(j,\text{"past"},c\_pools)$ Cell and carbon pool specific carbon stock of the pasture land pool mio. tC x x
$fm\_carbon\_density(t,j,land,c\_pools)$ Carbon density in vegetation, soil and litter tC per ha x x
$vm\_dem\_feed(i,kli,\text{"pasture"})$ Regional feed demand for biomass from pastures ton DM x
$vm\_yld(j,kve,w)$ Yields (variable because of technical change) ton DM per ha x
$pcm\_land(j,\text{"past"},si)$ Si-specific pasture land pool of the previous time step mio. ha x x
$vm\_land(j,\text{"past"},si)$ Si-specific pasture land pool of the current time step mio. ha x x
$vm\_prod(j,\text{"pasture"})$ Cell specific production of pasture biomass mio. ton DM x

The last columns of the table indicate the usage in the different realizations (numbered with capital letters)

Output

Name Description Unit
$vm\_cost\_past(i)$ Regional pasture production costs mio. US$

Interface plot


Figure 0: Information exchange among modules

Realizations

(A) static

In this implementation, pasture is fixed to the observed 1995 patterns [Erb et al1 (2013), Krause et al2 (2013)]. Correspondingly, also its carbon stock is fixed.
Regional production costs associated with pastures are set to zero.

\begin{equation}
vm\_land.fx(j,\text{"past"},si) = pcm\_land(j,\text{"past"},si) \\
vm\_cost\_past.fx(i) = 0 \\
vm\_carbon\_stock.fx(j,\text{"past"},c\_pools) = \sum_{si}(pcm\_land(j,\text{"past"},si)*icm\_carbon\_density(j,"past",c\_pools))
\end{equation}

Limitations:
There are no computational limitations to this module realization. Since pasture area is fixed, it does not respond to future demand trajectories and trends in the land use and agricultural sector like intensification pathways, increasing production of animal products, bioenergy production and afforestation on former pasture area. This may lead to an inconsistent overall picture of land use dynamics.

(B) endo_jun13 (default)

In this implementation, the required production level of biomass from pasture is determined by the sum of product-specific regional pasture demand as calculated by the livestock module (70_livestock):

\begin{equation}
\sum_{cell(i,j)} vm\_prod(j,\text{"pasture"}) \geq \sum_{kli}vm\_dem\_feed(i,kli,\text{"pasture"}) - i31\_scavenging(i),
\end{equation}

where we subtract the excess demand for pasture biomass which is fulfilled by scavenging (not further allocated to a certain area):

\begin{equation}
i31\_scavenging(i) = f31\_pasture\_demand_1995(i) - f31\_pasture\_production\_1995(i).
\end{equation}

Production of pasture biomass is restricted to pasture area which is delivered as module output together with the resulting geographically explicit production of pasture biomass. Cellular production is calculated by multiplying pasture area vm_land(j,"past",si) with cellular pasture yield vm_yld(j,"pasture","rainfed") which is delivered by the 14_yields module where increases of pasture yields are linked to the technological development path of the crop sector:

\begin{equation}
vm\_prod(j,\text{"pasture"}) = \sum_{si}(vm\_land(j,\text{"past"},si)*vm\_yld(j,\text{"pasture"},\text{"rainfed"})).
\end{equation}

On the basis of the required pasture area, cellular carbon contents are calculated:

\begin{equation}
vm\_carbon\_stock(j,\text{"past"},c\_pools) = \sum_{si,ct}(vm\_land(j,\text{"past"},si)*fm\_carbon\_density(ct,j,\text{"past"},c\_pools)).
\end{equation}

Related regional production costs associated with pastures are currently set to zero:

\begin{equation}
vm\_cost\_past.fx(i) = 0.
\end{equation}

Limitations
No consideration of pasture management and systemic differences between extensive and intensive grazing systems.

Definitions

Name Description Unit A B
$i31\_scavenging$ Scavenging in DM pasture equivalents mio. t DM x
$f31\_pasture\_production\_1995(i)$ Biomass production as simulated by LPJmL on observed 1995 pasture areas mio. t DM x
$f31\_pasture\_demand\_1995(i)$ Feed demand for biomass from pastures in 1995 mio. t DM x

The last columns of the table indicate the usage in the different realizations (numbered with capital letters)

Developer(s)

Isabelle Weindl, Jan Philipp Dietrich

See Also

core, 70_livestock, 14_yields, 39_landconversion, Overview

References

1 Erb, K.-H., Gaube, V., Krausmann, F., Plutzar, C., Bondeau, A., Haberl, H., 2007. A comprehensive global 5 min resolution land-use data set for the year 2000 consistent with national census data. J. Land Use Sci. 2, 191–224. doi:10.1080/17474230701622981

2 Krause M., Lotze-Campen H., Popp A., Dietrich J.P., and Bonsch M. 2013. “Conservation of Undisturbed Natural Forests and Economic Impacts on Agriculture.” Land Use Policy 30 (1): 344–54. doi:10.1016/j.landusepol.2012.03.020.