Abstract

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.

Keywords

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

Published in

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

SLU Authors

• Bargaz, Adnane

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    
  • University of Toronto

• Jensen, Erik Steen

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

• Carlsson, Georg

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

Associated SLU-program

SLU Plant Protection Network


UKÄ Subject classification

Agricultural Science
Ecology
Soil Science


Publication identifier

DOI: https://doi.org/10.1016/j.apsoil.2017.08.011

Permanent link to this page (URI)

https://res.slu.se/id/publ/90946