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

The aim of this study is to evaluate the antioxidant activity of dried fruit extracts of Zizyphus jujubaMill. Polyphenols and flavonoids content determined in aqueous extract (aq), hydromethanolic (EM), hydroacetonic (EA) extracts, and their ethyl acetate (Acet) andn-butanol (n-but) fractions reveal variable rates; 42.84–94.70 mg gallic acid equivalent per g extract and 47.02–427.33 mg catechin equivalent per g extract. The antioxidant activity was evaluated by different assays using total antioxidant capacity, 2,2-Diphenyl-1-picrylhydrazyl (DPPH), β-carotene bleaching assay, and ferric reducing antioxidant power (FRAP). In DPPH assay, all extracts showed an interesting scavenging effect, an estimated reduction rate about 75.58–97.71% was determined with the IC50(the half maximal inhibitory concentration) values ranging from 12 to 503.6 μg/ml. In β-carotene bleaching assay, 500 μg/ml of each extract showed a large inhibition (51.14–85.01%) with IC50values ranging from 48 to 462 μg/ml compared to butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tannic acid 0.6, 2.00, and 461 μg/ml, respectively. The results of FRAP show that the crude extracts (aq ˃ EM ˃ EA) are less efficient than their fractions (Acet/aq˃ Acet/EA˃n-but/EA) which demonstrate an important activity. Concerning total antioxidant capacity essay (TAC), the highest capacity was noticed for Acet/aq (71.98 μg gallic acid equivalents [GAE]/mg extract) and Acet/EA extract (64.62 μg GAE/mg of extract). The antioxidant activity of dried fruit extracts ofZ. jujubais mainly related to its polyphenol content essentially on flavonoids, which qualifies this species as a source of natural antioxidant.