Agriculture, Ecosystems and Environment 102 (2004) 365–375
Use of summer harvested common reed (Phragmites australis)as
nutrient source for organic crop production in Sweden
, Hans Fredriksson
Department of Agricultural Engineering, Swedish University of Agricultural Sciences,
P.O. Box 7032, SE 750 07 Uppsala, Sweden
Received 9 July 2002; received in revised form 5 August 2003; accepted 11 August 2003
Increasing nutrient levels in lakes contribute to environmental problems such as overgrowth and eutrophication. Decreasing
soil nutrient levels in organic farming systems result in reduced plant growth. During July and August, nutrient concentration
in aboveground parts of the widely distributed aquatic plant common reed (Phragmites australis) is relatively high. The
purpose of this work was to identify and analyse technical and logistic systems useful in removing reed biomass from the lake
and using it as nutrient supply in organic crop production. The area studied for reed harvest was limited to the “Kållandsundet”
drainage basin in Sweden. 160 ha are scheduled for harvesting each year.
One strategy studied was to chop the harvested material and spread it directly on farmland. Another was to compost
the material before spreading, and a third was to use the harvested biomass as raw material in biogas production and
spread the by-product (sludge) on farmland. The energy balances for the three systems were calculated to −0.35, −0.43
and +4.05 MJkg
harvested dry matter, respectively.
The biogas strategy produces both large amounts of energy in the gas and nutrients in a form easily available to agricultural
plants. The economics of the system are sensitive to changes in income provided by the gas produced and in the cost of
the chopping operation. The alternative of chopping and spreading the reed directly as green manure does not require large
investments or complicated processing plants, but produces no useful energy and the risks for nitrogen leakage are higher than
for the biogas alternative. The compost alternative has the least favourable characteristics among the three strategies studied.
The operations at the compost plant are costly and no useful energy is produced. For all three alternatives, the total economics
are highly improved if the positive effects of nutrient removal from the lake are included in the calculations.
© 2003 Elsevier B.V. All rights reserved.
Keywords: Phragmites australis; Common reed; Organic agriculture; Biogas; Compost
A goal of the Swedish government is that 20% of
the national crop production area should be organically
grown by the year 2005. Many organic farms in the
Corresponding author. Tel.: +46-18-671877;
E-mail address: firstname.lastname@example.org (P.-A. Hansson).
EU are managed as stockless systems, concentrating
on crop production, and these stockless, or all-arable,
systems are becoming increasingly important in or-
ganic farming (Schmidt et al., 1999).
Nutrients are removed from the soil, for example,
by leaching and in the harvested crop. The use of ar-
tiﬁcial fertilisers is not allowed in organic agriculture
and the supply needed to balance the removal of nu-
trients is therefore a crucial question (Watson et al.,
0167-8809/$ – see front matter © 2003 Elsevier B.V. All rights reserved.