The use of a newspaper/horse manure compost as an alternative to peat-based
compost or coir fibre was assessed by comparing various physical, chemical
and biological properties. The concentration of nitrogen in the newspaper/
horse manure compost (1.7%) was significantly greater than the nitrogen con
centrations in the peat-based compost (1.3%) and coir fibre (0.9%). The con
centrations of potassium, magnesium, calcium and phosphorus were similar in
all substrates, as were pH values, while the water holding capacity was tw
ice as high in coir fibre as in peat-based or newspaper/horse manure compos
ts. Toxicity tests, carried out using a cress bioassay, gave a germination
index for newspaper/horse manure compost of 6896, higher than for peat-base
d compost or coir fibre (6776 and 6632, respectively) indicating that no in
hibitory compounds were present. Tomato plants were grown in each substrate
for nine weeks to assess the usefulness of the different substrates. The p
lants grew well in all substrates and no significant differences in biomass
(shoots, roots or leaves), or in the nutrient concentrations of leaf mater
ial, could be detected. The chemical and biological properties of the newsp
aper/horse manure compost suggest that this compost could be used as an alt
ernative to peat-based compost and could provide a technology to utilise la
rge quantities of waste paper. (C) 2000 Elsevier Science Ltd. All rights re
served.