Examensarbete Handledare: Kerstin Berglund Lars Ericson

ABSTRACT
The anaerobe respiration ofmicroorganisms and plants promotes production oftoxic substrate
like carbon dioxide and ethanol in both plant and soil. Ice and standing water limit the possibility
for plants to exchange gases, which causes a deleterious situation for the plants. The
problem of damage to plants during winter dormancy because of ice and standing water is a
problem foremost in areas with flat topography and unstable winter c1imate (periods of freezing
and thawing).
The purpose of this study was to do an literature inventory of different types of damage in
grassland during dormancy and to study the result from field experiment with surface
drainage system and see ifthe system would reduce damage done by ice and standing water.
The purpose was also to study the range of winter damage in grassland in the coastal area of
Norrbotten and Västerbotten and to study different ways to overcome the problem at a
number of selected farms. The problems with winter damage in grasslands in northem
Sweden were investigated with help of a questionnaire. The inquiry was done among dairy
farmers during the summer 200l.
The literature review showed different factors causing winter damage in grassland. The
different groups were farming, c1imate, biotic and plant physiologic factors. Expect for these
four groups, the topography and the soil type also have an effect on the possibility for over
wintering. Late last harvesting of silage, soil compaction and late supplying of nitrate
fertilizer are farming factors that increase the risk of winter damage in grassland. Upfreezing
of plants, standing water and ice in grassland are examples of c1imate factors causing winter
damage in grassland. Fungi damage in grassland is a biotic problem. Deep snow cover that
longs for a long time increase the risk of fungi damage in grassland. An example of plant
physiologic is plant hardening. If the plant has a good hardiness the chance to overcome the
winter problems increase.
The conc1usion ofthe field experiment could not give any unambiguous results but years with
problems during winter, grassland on fields with surface drainage system seems to manage
the problems better than grassland on flat fields. The results from the questionnaire showed
that winter damage in grassland by ice and standing water is a problem both in Norrbotten and
in Västerbotten. The problem was more frequent in Västerbotten. The reason for this distinction
is the difference in topography and c1imate between the both counties. The coastal
region in Västerbotten is more flat and has more unstable winter c1imate than Norrbotten and
because of that Västerbotten can be subjected for more and longer periods of thawing
weather. Farmers that had not reported soil compaction did not have any problems with winter
damage in grassland caused by ice and standing water. On farms with extensive winter damage
in grassland the majority ofthe farmers had accomplished measures to limit the problem.
In areas with extensive problems ofice and standing water asurface drainage system can be a
good investment for good quaiity and quantity of grass. The results from the questionnaires
confirm the field experience results showing that topography and c1imate are two very important
factors causing problems in grassland due to ice and standing water. Farm management
can change the topography and the permeability of the soil. Surface drainage systems, drain
systems, surface run-off inlets and measures to minimise soil compaction are examples of
measures to prevent winter damage ofice and standing water.
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