Swidden Agriculture: Ancient Systems in Transition Sustaining Food ...

Weed management
Weeds rarely establish or adversely affect crop yields in integral, long fallow swidden systems. A short
cultivation : long fallow prevents establishment of grasses, composites and other weed species. Fields
are fallowed when yields begin to decline and weeding requirements increase. If cultivation periods are
lengthened or fallows shortened, disturbance associated invasive species can quickly establish.
Throughout Southeast Asia, excessive cultivation, shortened fallows, logging and other disturbances
have led to widespread establishment of exotic invasive weeds. One of the most problematic species is
Imperata cylindrica, a grass of African origin. Why might a grass from Africa be particularly well adapted
to anthropogenic disturbances?
Siebert (1987)