AUTHOR=Zhang Deshan , Zhang Yuqiang , Zhao Zheng , Xu Sixin , Cai Shumei , Zhu Haitao , Rengel Zed , Kuzyakov Yakov 

TITLE=Carbon–Phosphorus Coupling Governs Microbial Effects on Nutrient Acquisition Strategies by Four Crops

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.924154

DOI=10.3389/fpls.2022.924154

ISSN=1664-462X

ABSTRACT=<p>Plants adjust root morphological and/or exudation traits in response to phosphorus (P) mobilization mediated by microorganisms. We hypothesized that straw application coupled with P fertilization would influence microbial P and then root nutrient-acquisition strategies related to crop growth. Root morphological (length and average diameter) and exudation traits (acid phosphatase and carboxylates) of <italic>Brassica chinensis</italic>, <italic>Solanum lycopersicum, Lactuca sativa</italic>, and <italic>Vigna unguiculata</italic> in response to microbial P dynamics were characterized in no-P and P-fertilized soil with/without straw addition. Straw addition increased the growth of fungi and bacteria, stimulating microbial P immobilization at day 24. The high microbial abundance was associated with four tested crops having short roots in straw-amended compared with no-straw soil at day 24. In straw-amended soil, <italic>B. chinensis</italic> and <italic>S. lycopersicum</italic> shifted toward root P-acquisition strategies based on fast elongation and strong carboxylate exudation from days 24 to 40. Such effective root P-acquisition strategies together with microbial P release increased shoot P content in <italic>S. lycopersicum</italic> in straw-amended compared with those without straw at day 40. Conversely, <italic>L. sativa</italic> and <italic>V. unguiculata</italic> produced short roots in response to the stable (or even increased) microbial P after straw addition till day 40. In straw-amended soil, high P application stimulated root elongation and carboxylate exudation in <italic>L. sativa</italic> and <italic>V. unguiculata</italic>, whereas carboxylate exudation by <italic>S. lycopersicum</italic> was decreased compared with the straw-amended but non-fertilized treatment at day 40. In summary, root P-acquisition strategies in response to microbial P differed among the tested crop species. Phosphorus fertilization needs to be highlighted when returning straw to enhance P-use efficiency in vegetable cropping systems.</p>