Epsilon Archive for Student Projects

Abstract

Climate change affects agriculture all over the world and in the Northern hemisphere the change
towards warmer temperatures is more rapid than other parts on the planet. As this progresses the
need to produce food in a sustainable way and stabilize or increase yields is essential. In Sweden, as
well as the rest of the world, the trend in the 20th centaury has been to produce large quantities of
food in an intensified large-scale cropping system where a short crop rotation or monoculture has
been the norm. One of the fears in agricultural research during the 1950s was what effect these
cropping systems would have on soil properties and yield over time. In order to evaluate these
effects, a number of long-term field experiments (LTEs) were established during the 1950-1960s.
LTEs gives important information about what is beneficial for the soil and crops over time and in
that way, what is beneficial for our food production. For a sustainable food production, it is crucial
to know what an agricultural system should include to be resilient and sustainable over time.
In this thesis an LTE in northern Sweden, established in the 1950s with 4 different cropping systems
and different 6-year crop rotations, was analysed for the effects on barley and ley yield. The results
suggest that having an animal-based cropping system with longer ley-years, 5 years, reduces the
depletion of soil organic carbon and produce a significantly higher yield trend for barley yield over
time compared to cropping systems with 0–2 years of ley in the rotation. The results also suggest
that cropping systems with shorter ley-years, 2-3 years, result in significantly higher first year ley
yield trends over time, compared to a cropping system with 5 years of ley.