Editorial Introduction to Volume I 11In the final chapter of this section, Pedro Sanchez and colleagues set out the
themes and challenges for alternatives to slash-and-burn agriculture. Known also
as shifting, swidden, milpa, shamba, jhum and kaingin agriculture, slash-and-burn
has long been a sustainable and persistent form of agricultural system in the forests
of the tropics and sub-tropics. Trees are cleared, crops grown for 1–2 years, live-
stock then grazed, and then the community moves to cut another area of the for-
est. Provided they do not return for 20–30 years to the same plot, then sufficient
time elapses for the forest fully to regenerate, and the system can persist over long
periods. But when total forest cover declines, through logging, ranching or other
development projects, or population increases, then the rotation cycle shortens,
and the system cannot retain its fertility and success. In some quarters, small farm-
ers engaged in slash-and-burn are blamed for the destruction of tropical rainfor-
ests, but in truth it is other pressures that have made their management systems no
longer viable. This chapter documents the recent international efforts to produce
effective alternatives to slash and burn for the roughly 40 million people (2 per
cent of the world’s agricultural population in the tropics) of Latin America, Africa
and Asia who currently rely on these systems of management. Lands can be reha-
bilitated with the right scientific and technological innovations, as well as the
appropriate social, economic and policy support.
Part 4: Modern Agricultural Reforms
The knowledge that soil erosion was both costly and damaging was first appreci-
ated on a wide scale by agricultural authorities in the US and colonial Africa and
India in the early part of the 20th century. They took the view that farmers were
mismanagers of soil and water, and so had to be encouraged to adopt conserving
practices. Erosion was considered a technical problem requiring only technical
action, and so authorities encouraged farmers to construct terraces, bunds (embank-
ments of soil), ditches and drains, and to adopt alternative cropping patterns and
contour planting. They also resettled people to discourage the use of certain lands,
and destocked other regions of livestock to reduce grazing pressure.
The first chapter in this section by Pretty and Shah describes how this style of
intervention was first established in the US. It emerged followed the period of
severe wind erosion and dust storms that came to be known as the Dust Bowl of
the early 1930s. Even though there were subsidies to encourage farmers to adopt
new measures, authorities were granted wide-ranging powers to enforce land use
regulations. This pattern of intervention was then repeated by colonial authorities
in Africa and Asia. Early regulations had been adapted to local conditions and were
grounded in farming and grazing practice. But later, administrators travelling to
the US saw the devastation, and brought back recommendations for large-scale
bunding and ridging, combined with contour ploughing and planting. Locally
adapted practices were largely ignored, even though they were more effective in