Use of aquatic macrophytes in water treatment for the corn and sorghum culture

Abstract

Water quality from artificial wetlands on the first growth stages of sorghum (Sorghum bicolor cv. D65) and corn (Zea mays cv. DK 2002) was evaluated. An experiment of three ponds serial system seeded with junco (Scirpus americanus), tule (Typha latifolia) and aquatic liry (Eichhornia crassipes) was conducted. Water was introduced into each pond with a retention time of 15 days. Decreases in all parameters were observed, with exception of the ion nitrate (0.60 to 0.82 mg/l) and the electrical conductivity (34.4 at 66.4 (mS/cm. Diminution in the pH (8.33 to 7.29), as well as the COD (416 to 120 mgO2/l), the ion calcium (6.6 to 0.54 mg/l), the ion chloride (0.011 to 0.002 mg/l), the nitrite (0.234 to 0.040 mg/l), the ammonium (1.451 to 0.0003 mg/l) and the phosphate (10.3 to 2.3 mg/l) were obtained; the Pb and Cd values were below the permissible limit. The total and fecal coliforms decreased in each treatment with a final reduction of 94.17 % and 91.25 %, respectively. Both crops had significant root growth inhibition: sorghum showed a 1.69 cm value in root growth in treated water, 3.0 cm in distilled water and 2.11 cm in the control (untreated water). A 2.78 cm root growth was observed in corn with treated water, 3.05 and 3.35 cm were the values for the distilled water and the control treatments, respectively. The system was efficient in terms of sanitary quality and the reduction of ammonium, calcium, phosphates and COD, but not for salts concentration.