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The intercropping cowpea-maize improves soil phosphorus availability and maize yields in an alkaline soil

Latati, M., Blavet, D., Alkama, N., Laoufi, H., Drevon, J. J., Gérard, F., Pansu, M., Ounane, S. M.
Plant and soil 2014 v.385 no.1-2 pp. 181-191
Vigna unguiculata, Zea mays, acidification, alkaline soils, biomass, continuous cropping, corn, cowpeas, fallow, field experimentation, grain yield, intercropping, pH, phosphorus, rhizosphere, soil respiration, symbiosis, Algeria
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-CO₂from 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.