Cultivated peat soils

Yesterday, today and tomorrow

AgrD. Örjan Berglund

What is peat soil?

What is peat soil?

• Formed when the degradation of organic material is hampered due to oxygen deficiency and cold climate

• Contains > 40% organic material

• Have very high porosity and can hold large amounts of water

• Usually low pH

• Needs drainage for crop production and trafficability

Kälkestad

History

History

• The interest in using peatlands for agriculture started in

the beginning of the 18th century due to population

increase and the utilitarian spirit of the time

• In the 1940s there were about 700.000 ha of cultivated

peat and gyttja soils

200 000

205 000

210 000

215 000

220 000

225 000

230 000

235 000

240 000

0

10 000

20 000

30 000

40 000

50 000

60 000

70 000

80 000

90 000

100 000

1999 2005 2006 2007 2008

Are

a (h

a)

Are

a (h

a)

Year

Sum

Row crops

Annual crops

Set aside land

Ley

Pasture

Tree plantation

Wetland

Other

• 240.000-270.00 ha cultivated organic* soil

• Less intensive cultivation compared to mineral soils

* Organic soil = peat, gyttja and marl

Present

Problems

Peat soils need drainage

CO2

Drained

peatlands

CO2 sources

N2OCH4

CO2

CO2 CO2 CH4 N2O

Gas dynamics in peatlands

(CO2 carbon dioxide, CH4 methane, N2O nitrous oxide)

Pristine

mires

CO2 sinks

Greenhouse gas emissions from

cultivated peat soils

• Calculated from subsidence and bulk density

– 3.1-4.6 M ton CO2 eq./ year

• From emission measurements

– 4 M ton CO2 eq. /year

1 million cars that travel 20.000 km/year (6-8% of

Swedens reported emissions)

The Future; New Ruralities

• Bioenergyprojects

– BIOM

– Fårträsk, Malå

– Knaften, Lycksele

• Use sewage sludge

– Decrease CO2 emission

• Use foundry sand

– To increase bearing capacity

• Small scale and local use of biogas

– To get economy in the production

The End