Diversity enhances agricultural productivity via rhizosphere phosphorus facilitation on phosphorus-deficient soils

doi:10.1073/pnas.0704591104

Diversity enhances agricultural productivity via rhizosphere phosphorus facilitation on phosphorus-deficient soils

*Key Laboratory of Plant and Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094, China;
^§Institute of Soils and Fertilizers, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China; and
^‡Resource and Environmental College, Northeast Agricultural University, Harbin 150030, China

Communicated by G. David Tilman, University of Minnesota, St. Paul, MN, May 16, 2007 (received for review February 14, 2007)

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Fig. 1.
Biomass (dry weight of shoots plus roots) of maize (a), faba bean (b), and P uptake by maize (c) and faba bean (d) supplied with different P forms and grown in various treatments of root barrier between two species for 74 days (Greenhouse Study 1). Bar groups with different capital letters indicate a significant difference (P < 0.05) between forms of phosphorus treatment. Bars with different lowercase letters indicate a significant difference (P < 0.05) among three treatments of root interactions within the same phosphorus form or source. Error bar is a SD (n = 4) (Greenhouse Study 1).
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Fig. 2.
Visualization of rhizosphere acidification of faba bean (a), soybean (b), and maize (c). The roots were imbedded for 6 h in agar gel containing a pH indicator (bromocresol purple) without P supply (Greenhouse Study 2). Yellow indicates acidification, and purple indicates alkalization.
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Fig. 3.
Concentration of malate and citrate in the rhizosphere of maize, soybean, and faba bean. Harvests were at 35 and 45 days after emergence, respectively. Data from two samplings were combined into one data set as replicates because no significant difference was found between the two samplings. Differences among the letters above the bars indicate a significant (P < 0.05) difference in organic acids between crops (n = 11) (Greenhouse Study 3).

Footnotes

^†To whom correspondence may be addressed at:
College of Resources and Environmental Sciences, China Agricultural University, 2 Yuan Ming Yuan West Road, Beijing 100094, China.
E-mail: lilong{at}cau.edu.cn or zhangfs{at}cau.edu.cn