In eastern Zambia, population growth has reduced per-capita land availability to such an extent that traditional bush fallows can no longer be practiced, and low soil fertility is a major constraint to crop production. Improved fallows (IF) based on leguminous trees are a low cash-input agroforestry practice to restore soil fertility. The objective of the study reported here was to assess the adoption of IF by farmers who tested the technology, including the extent to which the technology is practiced relative to its potential scale.