Effects of pressmud and spentwash in integration with phosphogypsum on metallic cations build-up in the calcareous sodic soil

A field experiment to reclaim a calcareous sodic soil having sandy clay loam texture, pH 9.2, SAR 13.7, ESP 35, CaCO₃ 9.5% and medium in metallic cations (Fe, Mn, Zn and Cu) status was carried out for two consecutive years, 2001–2002 and 2002–2003 at Livestock Research Station, Vallabhnagar (Udaipur, Rajasthan). The treatments comprised of one time application of four levels of pressmud (0, 5, 10 and 15 t ha⁻¹) or spentwash (0.25, 0.5 and 0.75 million L ha⁻¹) in integration with three 1evels of phosphogypsum (0, 25 and 50% G.R.) in a randomized block design replicating each treatment thrice. The result of investigation indicated that the metallic cations (Fe, Mn, Zn, Cu, Ni, Cd and Pb) status increased as a consequence of incorporation of either pressmud or spentwash in integration with phosphogypsum during both the years of investigation. The highest value of metallic cations status of soil under study was recorded under the treatment receiving pressmud at 15 t ha⁻¹ or spentwash at 0.75 million L ha⁻¹ in integration with phosphogypsum at 50% GR. However, the status of these metallic cations in soil was within the permissible limit indicating that one time use of pressmud or spentwash as soil amendment is not hazardous for soil health and crop production.