LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 2A: LAND USE 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
Figure 1 Food availability in the Netherlands (kcal per person per day) from 1800 onwards (source: Knibbe
2007; Miedema 2011).
2.2 Changes in technology (yields)
For the major food crops used in The Netherlands yield data were available for 1855 to 2010. Fig. 2
shows the results. Large differences in yield improvements exist: the yield of rapeseed doubled in 150 years,
while the yield of wheat increased 5 times. Buckwheat disappeared from the agricultural system in the Netherlands,
only up to 1940 yield data were available. Between 1855 and 1900 not much change in yield was
observed. We assumed that in the years before (1800-1855) the yields were also constant. The increase in
yields after the Second World War is due to the increased use of fertilisers in The Netherlands: this increased
6 times from 100 mln kg to 600 mln kg.
For the production of milk grass is required. Yields for grasslands are very difficult to obtain, since grass
is not harvested and weighted, but cows consume it directly in the fields. Presently yields of grass are in the
order of 10 t/ha (Aarts et al., 2005). These yields imply fertilised grasslands. We assumed the development in
yields of grasslands followed the same pattern as wheat. This implies that grassland yields were around 1
t/ha in the nineteenth century Crop yields' and increased development rapidly (1850-2000) after the second world war.
5
3
1
Potatoes
Wheat
Figure 2. Relative developments in crop yields in the Netherlands in the last 150 year (sources: Smits and
van der Bie, 2003, Sneller 1943.)
Rye
Sugarbeets
1850 1900 1950 2000
Barley
Rapeseed
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