Efficiency of phosphogypsum and mined gypsum in reclamation and productivity of rice-wheat cropping system in sodic soil

Abstract

In this study, efficacies of mined gypsum and phosphogypsum (PG), when applied at equivalent doses, were compared for sodic soil reclamation and productivity of rice–wheatsystem.ApplicationofPG,followedbykarnalgrassasfirstcrop,resultedin the greatest reduction of soil pH and exchangeable sodium percentage (ESP) followed byPGappliedat10Mgha−1 alone.ApplicationofPGat10Mgha−1 resultedingreater yieldsofbothriceandwheatthanothertreatments.Ditheylenetriaminepentaaceticacid (DTPA)–extractable micronutrients of PG-treated soil were greater than in mined gypsum–treated soil. A greater portion of applied P entered the calcium (Ca)–phosphorus (P) fraction in PG-treated soil, which also resulted in more soluble P than the mined gypsum–treated soil. Phosphogypsum effected greater increase in aggregation, soil organic carbon, microbial biomass carbon, and aggregate associated carbon and decrease in zeta potential, leading to increased hydraulic conductivity and moisture retention capacity in soil over mined gypsum–treated soil