large scale impacts of grassland management and changes in livestock production...
TRANSCRIPT
Large scale impacts of grassland management and changes in livestock production systems
Susanne Rolinski, Isabelle Weindl, Jens Heinke, Benjamin Bodirsky,
Anne Biewald and Hermann Lotze-Campen
15.10.2014
Grassland productivity and livestock production
MAgPIE
global agro-economical model
• feed baskets for livestock production systems
• livestock products
• landuse pattern
LPJmL
global vegetation and crop model
• grass growth and yield
• management of pasture
Grass in LPJmL So far
• frequent mowing
• dependence on grass productivity
New
• mowing and grazing
• difference in frequency and intensity
• fate of NPP differs
feedback of grazing and mowing on productivity
Grass management options Default option • harvest when
leaf biomass > 100 g C m-2
• removed biomass is 50% of leaves
• goes to harvest removal from paddock
Grass management options Extensive grazing • during the entire
vegetation period grazing of biomass by cattle
• low density (~ 0.5 LSU ha-1)
• removed biomass goes to cattle, soil and atmosphere
Varying LSU ha-1
(g C m-2)
(g C m-2 a-1)
(g C m-2 a-1)
Average 1998 – 2002
Numbers: xx means x.x LSU ha-1
Optimal LSU
maximum harvest under grazing
livestock density under which maximum harvest is achieved
(g C m-2 a-1)
(LSU ha-1)
Optimal LSU
maximum harvest under grazing
9.3 GT C
livestock density under which maximum harvest is achieved
13975 Mio LSU
(g C m-2 a-1)
(LSU ha-1)
Optimal LSU
… but the world is not only grassland
What is the potential compared to current numbers?
current landuse pattern
current numbers in land-based systems
current numbers in all systems
Livestock numbers (Mio LSU) 2754 44.7 256
Grass harvest (GT C) 1.75 0.07 0.32
multiply pasture area and sum
GLW data in production systems LGA, LGH, LGT and their grazing demand
same for all livestock production systems
Conclusion and Outlook
• Integrated assessment of livestock
• production
• feed demand
• impact on land use, water use, emissions, prices
• requires
• link of production system to feed baskets
• description of transitions in production systems and diets
Next steps:
grassland management link to production systems
transition between diets into landuse model
Special tribute to Pete Smith for sponsoring