Barley shoot biomass responds strongly to N:P stoichiometry and intraspecific competition, whereas roots only alter their foraging

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Aims: Root system responses to the limitation of either nitrogen (N) or phosphorus (P) are well documented, but how the early root system responds to (co-) limitation of one (N or P) or both in a stoichiometric framework is not well-known. In addition, how intraspecific competition alters plant responses to N:P stoichiometry is understudied. Therefore, we aimed to investigate the effects of N:P stoichiometry and competition on root system responses and overall plant performance. Methods: Plants (Hordeum vulgare L.) were grown in rhizoboxes for 24 days in the presence or absence of competition (three vs. one plant per rhizobox), and fertilized with different combinations of N:P (low N + low P, low N + high P, high N + low P, and high N + high P). Results: Shoot biomass was highest when both N and P were provided in high amounts. In competition, shoot biomass decreased on average by 22%. Total root biomass (per plant) was not affected by N:P stoichiometry and competition but differences were observed in specific root length and root biomass allocation across soil depths. Specific root length depended on the identity of limiting nutrient (N or P) and competition. Plants had higher proportion of root biomass in deeper soil layers under N limitation, while a greater proportion of root biomass was found at the top soil layers under P limitation. Conclusions: With low N and P availability during early growth, higher investments in root system development can significantly trade off with aboveground productivity, and strong intraspecific competition can further strengthen such effects.

Original languageEnglish
JournalPlant and Soil
Issue number1-2
Pages (from-to)515-528
Number of pages14
Publication statusPublished - 01.08.2020

Bibliographical note

Open Access funding provided by Projekt DEAL. This work was supported by the BonaRes soil sustainability program of the Federal German Ministry for Education and Research (BMBF) for funding this research within the ‘INPLAMINT – Increasing agricultural nutrient-use efficiency by optimizing plant-soil-microorganism interactions’ project [grant numbers: 031A561A, 031A561H, 031B0508A, 031B0508H]. Acknowledgments

Publisher Copyright:
© 2020, The Author(s).

    Research areas

  • Ecosystems Research - Root system responses, vertical root distribution, specific root length, nutrient stoichiometry, Intraspecific competition