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Research article - Peer-reviewed, 2017

Species interactions enhance root allocation, microbial diversity and P acquisition in intercropped wheat and soybean under P deficiency

Bargaz, Adnane; Noyce, Genevieve L.; Fulthorpe, Roberta; Carlsson, Georg; Furze, Jessie R.; Jensen, Erik S.; Dhiba, Driss; Isaac, Marney E.


Belowground interactions in grain legume-cereal intercrops may improve resource acquisition and adaptation to environmental constraints such as phosphorus (P) deficiency. To advance the knowledge of belowground facilitative mechanisms involved in P-deficiency tolerance (root allocation, biochemical and microbial responses), soybean (Glycine max) and wheat (Triticum aestivum) were grown as monocrops and intercrops under P-deficiency and P-sufficiency conditions in soil-filled rhizoboxes. The hypothesis was that intercropping stimulates root microbial diversity, root biomass allocation and P-hydrolyzing acid phosphatases (APase) activity in roots under P-deficient conditions. Total root dry weight (RDW), length, and surface area significantly increased in P-deficient intercropped wheat and soybean. Greater root allocation to deeper soil layers was evident for P-deficient intercropped wheat. Shallow roots of intercropped wheat exhibited highly stimulated APase activity under P-deficient conditions while shallow roots of monocropped soybean exhibited higher APase activity in comparison to deeper roots, irrespective of P treatment. Root fungal diversity was significantly (p < 0.05) higher in intercropped wheat, and was significantly correlated with RDW, root APase activity, shoot P, and soil available P (rho = 0.24, p= 0.01). Root bacterial diversity was higher in both intercrops, and was significantly correlated with RDW and shoot N concentration. The observed shifts in root microbial diversity, root biomass allocation and APase activity provide explanatory mechanisms of relationships between rhizosphere heterogeneity and pathways for increased P acquisition in diversified crops. Advanced belowground metabolomics on root microbial communities are required to reveal the beneficial effect of root microorganisms in associations of different crop species.


Cereal; Legume; Phosphatase; Microbial diversity; Root distribution; T-RFLP54

Published in

Applied Soil Ecology
2017, Volume: 120, pages: 179-188