Our Indispensable Soil - Soil: Reflections on the Basis of our Existence - page 11



Feeling the urge. Conducting research in a developing country is very different from doing so in
Sweden. Many people inevitably become involved in the project. Some work as drivers or help
with sample collection. Others are civil servants from the various public authorities whose per-
mission is required. In certain countries, observers accompany researchers to ensure they abstain
from political activities. Everything takes time, but when you meet people with different per-
spectives and experience new environments, fresh questions are raised and the urge to carry out
research gains renewed impetus
The mycelia of mycorrhizal fungi help to bind soil particles into stable aggregates, preventing
erosion. The fungi grow better when nitrogen-rich compost is added to the soil. Here we are col-
lecting one of our first samples as part of a project to investigate the extent of fungal presence in
the Tunisian desert soil. Since then, the collaboration between Lund University and the Tunisian
research institute for agriculture, water and forests has continued to develop and grow

as touched Tunisian soil. Eventually the formalities ended and we were ready to
visit Hafedh's research area. Two turban-clad Bedouin carrying spades and pick-
axes clambered onto the back of our pickup truck and we sped off on a stony track
between the acacia trees. Our first stop was at the edge of the sparse forest, where
we wanted to find out if mycorrhizal fungi introduced earlier during the project
were colonising the local tree roots—and how far their hyphae extended through
the soil. I jumped out of the pickup, eager to start digging, but Hafedh shouted out
something about scorpions, whereupon our two companions began hacking at the
ground with their pickaxes. Once again, I was forced to stand idly by, until the two
men had excavated a hole big enough for Hafedh and me to examine the exposed
root structures. We were also accompanied by a group of suited officials of vary-
ing ranks, who watched as we decided where to take our first sample of Tunisian
soil. I solemnly filled a plastic bag with the soil in readiness for high-tech scien-
tific analysis in Sweden. The hope was that the results would indicate the extent to
which fungal presence was helping to improve the soil structure.
Lund University and the National Research Institute for Rural Engineering,
Water and Forestry in Tunisia have been working together for many years and our
knowledge of the role mycorrhizal fungi can play in improving eroded soil is con-
stantly evolving. Our initial studies of the acacias in Bou Hedma indicated that the
fungi which Hafedh had previously introduced to the soil there had been largely
ineffectual, both in terms of improving tree survival and soil structure. The fun-
gus, imported from Spain, was unsuited to Tunisian conditions. This led us instead
to try to improve the conditions for indigenous fungi already present in the soil,
which we did by adding nitrogen-rich compost. This promotes aggregate growth
and allows water to penetrate deeper into the earth. Addition of organic matter also
aids water retention.
One conclusion from my first African project was that nature is often best at
selecting the appropriate species for specific environments. If we set our sights
on finding a fungus that can be a silver bullet in combating erosion in different
types of natural environment, we are likely to look in vain. A preferable approach
is to create optimal conditions for local fungi in their home environments. Nor do
I believe the answer lies in genetically modifying organisms to make them more
effective. Rather, the way forward is simply to manage land more sustainably.