Pressmud alleviates soil sodicity stress in rice‐wheat rotation: effects on soil properties, physiological adaptation and yield–related traits

We assessed the improvement potential of pressmud – a sugar industry waste – on soil properties, physiological adaptation and yield-related traits in a rice–wheat rotation in sodicity-affected Ghaghar basin of Haryana, India. Large-scale (0.2–0.4 ha) participatory trials comprising two treatments, with (+PM) and without (–PM) pressmud, were conducted on 125 farmers' fields covering non-sodic (NS), slightly sodic (SS) and moderately sodic (MS) soils. Pressmud application (10 Mg ha) led to appreciable reductions in soil pH (1.6–3.6%) and exchangeable sodium percentage (ESP; 10.4–20.1%) with concomitant improvements in plant physiological and yield-related traits across different soil alkali classes, albeit to a greater extent in SS and MS soils than in NS soils. Compared to prevailing farmers' practices (–PM), transformative improvements in mean leaf relative water content (RWC) (4 and 7%), membrane injury (MII) (−12 and −14%), photosynthetic rate (Pn) (21 and 25%), stomatal conductance (gS) (26 and 21%), transpiration rate (E) (38 and 22%), proline (P) (−19 and −20%) and Na/K accumulation in shoot (NaK_S) (−24 and −22%) and root (NaK_R) (−23 and −27%) were observed in both rice and wheat grown under PM ameliorated soils. On an average, rice and wheat yields were increased by 15.8 and 14.6% in SS and 18.9 and 16.7% in MS soils, respectively, with pressmud application. Principal Component Analysis (PCA) showed significant correlations among highly weighted variables including physiological and yield-related traits to influence the rice–wheat productivity with PM addition in SS and MS soils. Sustained use of this organic waste in agricultural lands seems to be an affordable solution for overcoming sodicity-induced land degradation, and achieving developmental goals of environmental and livelihood security.