252 Environmental Biotechnology
In particular, the deleterious effects of various species of Phythium,Phytophthora
andFusariumas well asRhizoctonia solani, which is a major threat to many
kinds of young plants, are largely suppressed or controlled. For many years the
horticultural industry had been aware, anecdotally and from experience, that com-
posted tree bark suppressed root rots caused byPhytophthoraspp. Investigations
of this revealed that plants which require the presence of vasicular arbuscular
mycorrhizae (VAM), small fungi around the roots, which are intimately involved
in nutrient and water uptake, grow better in blends of soil and bark compost than
in methyl bromide treated soil alone. Various bacteria, fungi and yeast, largely
indigenous to the original compost, have subsequently been indicated as active
agents in the overall effect. The biological nature of the control has been estab-
lished in laboratory trials involving heat treatment or microwave exposure of the
compost. This significantly altered the microbial balance, resulting in progressive
inhibition of suppression and led to 100% plant mortality in some instances. On
this basis, the need to ensure that compost is not subjected to extreme tempera-
tures during storage or transport becomes a very obvious problem to be avoided
in any intended practical application.
The agricultural usage of biowaste-derived products has considerable poten-
tial, but public acceptability and quality assurance issues must be major concerns,
probably more here than in any other comparable sector. In the UK alone, farm-
ers have not been slow to learn the terrible consequences of consumer anxiety.
Bovine spongiform encephalopathy (BSE) and the passions raised by genetically
modified (GM) crops, or animals reared on them, entering the human food chain
has focused attention ever more clearly on supply chain issues. The ramifica-
tions, in both economic and social terms, of the foot and mouth disease (FMD)
outbreak, which paralysed the UK farming industry throughout 2001, has left the
rural community all too well aware of the meaning of biosecurity. Since today’s
agri-business is so largely dominated by the demands of the supermarkets, it is
neither unreasonable nor unlikely that guaranteed product quality would be a
requirement in any industry-wide standard. A clear precedent has already been
set in this respect with the involvement of the British Retail Consortium in the
evolution of the matrix safety code for the treatment and application of sewage
sludge to agricultural land. The drive towards so-called ‘organic’ farming has
already fostered a climate of proliferating, and typically widely differing, compost
acceptability criteria throughout the world. This is scarcely helpful to the average
would-be user of these products, often serving more to confuse than elucidate.
The prospect of widespread uptake in the growth of bioproduction crops in
the future has been suggested as one of the routes forward for agriculture. To
echo Senator Harkin’s words, farmed resources could well account for much of
what is currently derived from crude oil, either directly in the chemical sense
as an alternative source of the same product, or indirectly as substitutes. In the
final analysis, the acceptance of the latter will, inevitably, depend on factors
which are more societal and economic than scientific or technical and as such,