Maize-mucuna (Mucuna pruriens (L.) DC) relay intercropping in the lowland tropics of Timor-Leste

Timor-Leste is a small predominantly agrarian society based on subsistence agriculture with maize as the key staple crop and food. Maize cropping is predominantly shifting in a slash and burn system with weed management and soil fertility key issues to farmers. An increasing population and farmer reluctance to use inorganic fertilizer drive the need to find improved cropping systems. This experimental series from 2007 to 2012 was designed to evaluate relay-sown intercropped mucuna (Mucuna pruriens (L.) DC var. utilis) with maize as a low-input legume intercropping system for its potential in the management of weeds and soil fertility. Factors investigated include legume species, optimum sowing time for inter-crop with maize, comparison of maize sown sole v. maize intercropped with mucuna, weeding regimes, and the effects of crop sequences with mucuna. Delaying mucuna sowing time to approximately one month after maize planting is particularly critical. Comparing continuous sole-cropped maize with maize relay-sown with mucuna, intercropping significantly reduced the weed burden on maize - often completely eliminating weeds. In the South of the country over five rotational cycles the percentage maize yield advantage of cropping with mucuna v. sole-cropping was 132%, lifting maize yield from a mean of 0.94 t ha−1 from successive mono-cropped maize to a mean of 2.19 t ha−1 with mucuna. Participatory research with farmers is now required to encourage Timorese farmers to (re-)adopt this agronomic system in appropriate parts of the country.