Do Short‐Term Legume–Maize Sequences Outperform Maize Monoculture Regarding Biomass Production and P Use Efficiency Under P‐Restricted Conditions?

Background With their ability to efficiently acquire P, integrating legumes in phosphorus (P)‐inefficient cereal‐based rotations may enhance P use efficiency (PUE). However, previous studies on crop rotations have not linked growth gains of successive crops to the stimulation of soil P processes by legumes. Thus, knowledge gaps exist in the relevance of changes in soil induced by legumes for the growth and P nutrition of successive crops and the PUE of the entire crop rotation. Aim This study aims to address the abovementioned points by testing four short‐term crop sequences (alfalfa ( Medicago sativa )/maize ( Zea mays cv. Johaninio), faba bean ( Vicia faba cv. Augusta)/maize, white lupin ( Lupinus albus cv. Célina)/maize, and maize/maize) under P limitation and with the application of P fertilizers differing in their P availability (rock phosphate, struvite, and triple superphosphate) in a pot trial. Results Acid and alkaline phosphomonoesterase activity were strongly and persistently stimulated by white lupin and faba bean (2× for acid and 1.22–1.23× for alkaline phosphomonoesterase activity). However, even under P limitation, biomass and P offtake of successive maize did not benefit from the previous cultivation of legumes. In contrast, lupin strongly inhibited the growth of successive maize (0.4× aboveground biomass of maize after maize), although lupin increased calcium‐acetate extractable P. None of the legume‐based early growth sequences could compete with maize monoculture regarding PUE due to the low aboveground biomass of legumes compared to pre‐crop maize. Conclusion This study questions the one‐sided positive portrayal of legumes in crop rotations for improving the P nutrition of succeeding maize and can guide the design of future field experiments.