Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2010
Publication Date: 1/31/2011
Citation: Ahmad, H.R., Ghafoor, A., Corwin, D.L., Aziz, M.A., Khan, S., Sabir, M. 2011. Organic and inorganic amendments affect soil concentration and accumulation of cadmium and lead in wheat in calcareous alkaline soils. Communications in Soil Science and Plant Analysis. 42:111-122. Interpretive Summary: Throughout the world, particularly in developing countries, raw effluent is applied to agricultural fields as a means of disposal and of providing nutrients to crops. Aside from potential pathogen problems, the land application of raw sewage has potential detrimental effects due to the accumulation of heavy metals in soil, such as cadmium (Cd) and lead (Pb), and their movement into plants, which pose a threat to the plant and to the animal consuming the plant. A study was conducted to determine if organic (manure) and inorganic (calcium carbonate and gypsum) amendments could reduce the availability of Cd and Pb to wheat as a means of mitigating this detrimental effect of land application of raw effluent. Results showed that the inorganic and organic amendments decreased extractable Cd and Pb in soil and reduced their uptake in wheat by binding the Cd and Pb to carbonate. Although not a panacea, the approach can temporarily lessen the availability of Cd and Pb for uptake by wheat.
Technical Abstract: Irrigation with untreated effluent in periurban agriculture could result in accumulation and bioconcentrations of cadmium (Cd) and lead (Pb). Different amendments were used to investigate their effect on availability, concentration, and uptake of metals by wheat in texturally different soils. Crop was irrigated with water containing Cd and Pb at 20 mg/L, thereby adding 260 mg pot-1 of each metal. Amendments included calcium carbonate at 6 or 12%, gypsum at 50 or 100% of the soil gypsum requirement, farm manure at 7.50 or 15.00 g kg-1 soil, and a control. Amendments decreased ammonium bicarbonate diethylenetriaminepentaacetic acid (AB-DTPA)–extractable Cd and Pb concentrations and uptake by wheat. Dry matter, concentration, uptake, and extractability of Cd and Pb were greater in sandy loam soil compared with those in sandy clay loam soil irrespective of amendments. Sequential extraction showed that more metals were extracted from the control in all fractions and that predominantly metals were found in the carbonate fraction.