Characteristics of Organic Acids from Root Exudation in Maize and Soybean Intercropping

By hydroponic experiment, collected root exudation of different growth stages in monocropped maize, monocropped soybean, separation intercropping maize and soybean(roots mesh barrier)and intercropping maize and soybean (roots no mesh barrier) and by HPLC method for analysis variation characteristics of organic acids from root exudates in the different planting modes, different growth stages of maize and soybean intercropping system. The results showed that compared with monoculture, in the kinds of organic acids, separation intercropping maize: malic acid was identified and maleic acid was not identified in seedling stage; No change in bell mouth period; Malic acid was not identified in booting stage. Intercropping maize: malic acid was identified in seedling stage; tartaric acid and malic acid were not identified in bell mouth period; Lactic acid and maleic acid were not identified in booting stage. Separation intercropping soybean: citric acid was identified in in seedling stage; Tartaric acid and malic acid were not identified and acetic acid was identified in flowering phase; Tartaric acid and malic acid were identified in seed filling period. Intercropping soybean: citric acid was identified in seedling stage; Tartaric acid and malic acid were not identified and acetic acid was identified in flowering phase; Tartaric acid and malic acid were identified in seed filling period, Lactic acid and maleic acid were not identified in seed filling period. The secretion rate of organic acids, separation intercropping maize was increased by 28480% in bell mouth period, intercropping maize was increased by 15924%, 8801% in bell mouth period and booting stage respectively. Intercropping soybean was increased by 14959% in seed filling period, separation intercropping soybean was increased by 11465%, 2424%, 38938% in seedling, flowering and seed filling stage respectively. Intercropping and separation intercropping affect kind of organic acids, Intercropping increased the rate of organic acid secretion of maize in the longer period, separation intercropping increased the rate of organic acid secretion of soybean root in the longer period.