A paper by Zhan Xu, who is currently doing her PhD at CSA, was selected among the most cited papers in Field Crops Research. The paper was written during Zhan's MSc study.
The paper's title is: "Intercropping maize and soybean increases efficiency of land and fertilizer nitrogen use; A meta-analysis" by Zhan Xu, Chunjie Li, Chaochun Zhang, Yang Yu, Wopke van der Werf and Fusuo Zhang.
The major challenge of agriculture is to reconcile these two needs: increasing food production while lowering environmental pollution. Intercropping, growing two or more crops simultaneously in the same field, has been called the “new green revolution”, since it can raise land productivity without increasing inputs. Cereal/legume intercropping is a classical crop combination in intercropping.
The researchers conducted a global meta-analysis to quantify the potential of maize/soybean intercropping in solving the conundrum of maintaining or even increasing maize and soybean production, while using less land and reducing environmental impact. Land and fertilizer use efficiency were assessed using as metrics the land equivalent ratio (LER) and the nitrogen fertilizer equivalent ratio (NFER). The worldwide average LER of maize/soybean intercropping was 1.32, indicating a substantial land sparing potential of intercropping over sole crops. And the mean NFER was 1.44, indicating that intercrops received substantially less fertilizer N than sole crops for the same product output.
Intercropping saved fertilizer due to concentrating production on less land with similar fertilizer N input per unit land. This meta-analysis thus shows that exploiting species complementarities by intercropping maize and soybean enables major increases in land productivity with less fertilizer N use.