POTATO INTERCROPPING SYSTEMS WITH MAIZE AND FABA BEAN

Potato is a major cash crop for Bhutanese highland farmers, who widely use intercropping systems combining potato (Solanum tuberosum) with maize (Zea mays). Scarcity of information on existing cropping practices limits the scope of present extension programs. Experiments evaluating potato intercropping systems with maize and faba bean (Vicia faba) were conducted at Yusipang (2700 m) and Kangma (1900 m). Potato yield reductions through intercropping ranged from 0-21 percent depending on year, and location. Variation in planting geometry and maize planting date did not affect potato yield reductions. The land equivalent ratio ranged from 1.03-1.06 for faba bean and from 1.11 to 1.49 for maize intercropping systems. Compared to potato as a sole crop maize intercropping increased gross benefits in Kangma by 12-15 percent with maize plant densities of 2.8 per m2. In Yusipang, gross benefits were not increased through intercropping. Reducing risks of environmental and market impacts favor the use of intercropping systems.