Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Plant and Soil 181-191 P availability Intercropping Biological N-2-fixation Rhizosphere acidification ALGERIE 2014 fdi:010063509 ENG Plant and Soil 0032-079X ISI:000345283400013 1-2 10.1007/s11104-014-2214-6 https://www.documentation.ird.fr/hor/fdi:010063509 https://www.documentation.ird.fr/intranet/publi/depot/2015-02-06/010063509.pdf 385 Horizon (IRD) Aim This study assessed whether growing cowpea can increase phosphorus (P) availability in the rhizosphere and improve the yield of legume-cereal systems. In alkaline Mediterranean soils with P deficiency, it is assumed that legumes increase inorganic P availability. Methods A field experiment was conducted at the Staoueli experimental station, in Algiers province, Algeria, to compare the growth, grain yield, P availability, and P uptake by plants with sole-cropped cowpea (Vigna unguiculata L. cv. Moh Ouali) and maize (Zea mays L. cv. ILT), intercropped cowpea-maize, and fallow. Results P availability in the rhizosphere was increased in both sole cropping and intercropping systems compared with fallow. It was highest in intercropping. The increase in P availability was associated with (i) significant pH changes of the rhizosphere of cowpea in sole cropping and intercropping systems, with the rhizosphere acidification significantly higher in intercropping (-0.73 units) than in sole cropping (-0.42 units); (ii) significant increase in the rhizosphere pH of intercropped maize (+0.49 units) compared to fallow; (iii) increased soil respiration (C-CO2 from microbial and root activity) in intercropping compared with sole cropping and fallow; and (iv) higher efficiency in utilization of the rhizobial symbiosis in intercropping than in sole-cropped cowpea. Conclusion With cowpea-maize intercropping, cowpea increased the P uptake, by increasing the P availability by rhizosphere pH changes in an alkaline soil. Overall, this study showed that intercropping cowpea improved the plant biomass and grain yield of maize in this soil. 068 ; 076 UR210 Algérie