Maize/peanut intercropping increases land productivity: A meta-analysis

Intercropping cereals and legumes can increase agricultural productivity and reduce inputs of nitrogen fertilizer but there is a need for further literature synthesis on the size of intercropping advantages and the factors affecting these advantages. Here we present a global meta-analysis of 36 studies, 66 experiments and 260 treatments addressing the land productivity of maize (Zea mays L.) and peanut (Arachis hypogaea L.) intercropping. Data were extracted from the literature and analyzed with mixed effects models to assess the land equivalent ratio (LER) and the factors affecting LER. The worldwide average LER of maize/peanut intercropping was 1.31 +/- 0.03. The LER did not vary with continent, intercrop planting pattern and temporal niche differentiation, but sowing maize earlier than peanut (relative sowing time: RSTm<0) increased the partial LER of maize without significantly decreasing the partial LER of peanut. Increased N rate increased the partial LER of maize and decreased the partial LER of peanut but did not affect the total LER. This meta-analysis shows that maize/peanut intercropping is more land use efficient than the sole crops, it attains on average a "win-no win" yield advantage and mainly due to the maize.