Our Indispensable Soil - Soil: Reflections on the Basis of our Existence - page 18

Vital infections. The image shows the nodules that form when the roots of an alder tree are colo-
nised by bacteria capable of capturing nitrogen from the air. The tree provides the bacteria with
energy and gains precious nitrogen in return. Alder is an opportunistic species, often first to
appear in the wake of avalanches and on soil that emerges when glaciers retreat, and good at sta-
bilising erosion-prone soil
other nutrients. One spin-off from Ecoslopes is a database detailing the properties
of different tree species and how they can be used to stabilise erosion-hit areas
internationally. Certainly, one must hope that initiatives of this sort will become
more widespread in Nepal in future.
Is Organic Farming Sustainable Agriculture?
Sustainable agriculture means a system in which nutrients circulate and are returned
to the soil in equal measure to the nutrients removed during harvesting. Nitrogen-
fixing plants can play a key role in this context by obviating the need to fertilise the
soil with nitrogen. The legendary Swedish author August Strindberg knew this when
he wrote The People of Hemsö in 1887. In the topic, Madame Flod invites Carlsson
to visit her farm on the island of Hemsö to educate her son, Gusten.
Gusten explained that harvesting land year in and year out depleted the vitality from the
soil, which needed to rest, just like Man. But Carlsson gave a correct, if somewhat hazy,
explanation of how the clover crop fertilised the earth rather than depleting it, and kept it
free from weeds.
'Well, I'd never heard of crops fertilising the soil,' replied Gusten, who could not
understand Carlsson's scholarly explanation of how grasses took most of their nutrition
'from thin air'.
Pesticides and artificial fertilisers are not used in organic farming. The focus is
on confining the nutrient cycle to the farm, for instance through keeping manure-
producing livestock. Animals are fed a mixture of grass and herbs that not only