Productivity of wheat (Triticum aestivum L.) intercropped with rapeseed (Brassica napus L.)

Recent advances in agronomy include better understanding of biodiversity in the ecosystem and mechanisms of interactions between crop species. Intercropping encompasses two or more crop species growing together. Enhanced biodiversity in intercropping systems can increase productivity, stability, resilience, and resource-use efficiency of the intercropped species compared with sole-cropping. Feasibility of different wheat–rapeseed intercropping patterns were evaluated under three nitrogen fertilizer rates (0, 60, and 120 kg N ha−1) across two experimental years. Besides sole-cropping of wheat (1:0) and rapeseed (0:1), three patterns of wheat–rapeseed intercropping were arranged in different ratios, including 3:1, 1:1, and 1:3. Rapeseed growth and development were influenced highly by inter-annual weather variability, which resulted in a low yield in the second year of the experiment. Total cropping system performance, as indicated by dry matter (per plant and per unit area) and grain yield production, increased with adding N fertilizer, especially in the drier year. Additional N fertilizer could only compensate the yield loss due to intercropping in that year. In terms of individual crop production, sole-cropping of wheat was superior to all intercrops under the environmental conditions of the Pannonian region. Overall, among wheat–rapeseed intercropping patterns, the ratio of 3:1 had advantages over the other intercropping patterns in terms of productivity and interspecies competition across contrasting years.