Co-composting of chestnut burr and leaf litter with solid poultry
õguez, M. Diaz-Ravi
na, M. V
õa de los Alimentos, Universidad de Santiago de Compostela, Escuela Polit
ecnica Superior, 27002 Lugo, Spain
Received 11 September 2000; received in revised form 4 October 2000; accepted 13 October 2000
A co-composting of chestnut burr and leaf litter mixed with solid poultry manure was assessed by comparison of several
chemical, physicochemical and biological parameters. The ®nal pH of the co-compost was 8.89 and the C/N ratio was 13. The
germination index (GI) obtained using the co-compost varied with the seeds used. It was 155.35% for ryegrass seeds, 56.56% for
wheat seeds and 100% for barley seeds. The co-compost was mature in 103 days from a biological point of view. Ó 2001 Elsevier
Science Ltd. All rights reserved.
Chestnut (Castanea sativa Mill.) is an important
species in Galicia, North-western Spain, and cultivars
for nut and timber production have been reported since
the Middle Ages. An important waste in these cultivars
is a mixture of burr and leaves that can be the origin of
Composting of chestnut burr and leaf litter could be a
simple and low-cost way to prevent forest ®res if its
de®cit in nitrogen and moisture were supplemented with
a co-composting material. Poultry farms generate solid
manure from the deep litter which contains signi®cant
quantities of lignocellulosic materials, ammonia nitro-
gen and moisture (Georgakakis and Krintas, 2000).
Therefore, the transformation of chestnut burr and
leaf litter mixed with solid poultry manure into compost
would be a good use of both these wastes.
The main purpose of this study was to evaluate the
possible co-composting of chestnut burr and leaf litter
with solid poultry manure and its use as a fertilizer.
Physicochemical characterisations of the initial and ®nal
materials and germination indices for several seeds were
Burrs and leaves from the chestnut litter and solid
poultry manure from the deep litter were collected from
a local cultivar and a local farm, respectively. The basis
of the deep litter was pine chips. Reactors for compo-
sting experiments were built. Polyurethane (3 cm
thickness) was formed into the walls of plastic vertical
boxes with covers. The volume of each reactor was 108.8 l.
The temperature was measured during the composting
and before sampling. The mass was aerated by removing
the whole mass manually before sampling or daily when
the temperature was higher than 60°C. Samples of 150 g
each were taken at random during the composting.
Chemical analyses and germination indices were carried
out in triplicate and results given are averages.
The pH was determined in the aqueous extract of a 5 g
aliquot of a sample with distilled water at a solid:water
ratio of 1:25 (w/v). Moisture was determined by drying
at 105°C for 24 h, and total organic matter content
(TOMC) determined by weight loss on ignition at 540°C
for 16 h. Total carbon content (TCC) and oxidizable
carbon content (OCC) were estimated by the expressions
proposed by Navarro et al. (1990)
TCC TOMC À 9X33a1X745Y
OCC TOMC À 15X356a1X805X
Total nitrogen content was determined by Kjeldahl di-
gestion and steam distillation (Guitian Ojea and Car-
ballas, 1976). Inorganic nitrogen (NO
±N and NH
Bioresource Technology 78 (2001) 107±109
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