Ameliorating alkaline dispersive subsoils with organic amendments: Are productivity responses due to nutrition or improved soil structure?

Abstract Background and aims Alkaline dispersive subsoils are characterised by multiple physicochemical constraints that limit plant water nutrient acquisition. Subsoil amelioration through organic amendments (OAs) requires significant financial investment. Whereas large yield responses can result following amelioration, sometimes small or even negative occur, resulting in a net loss for the farmer. For farmers to feel confident investing subsoil better prediction of likely improvement is required achieve this an understanding underlying mechanisms such as nutritional non-nutritional drivers, longevity benefits required. Our study aimed ascertain drivers improvements from with OAs. Methods In controlled environment, wheat ( Triticum aestivum L. cv. Scepter) plants were grown until maturity Solonetz amended (i) poultry litter (PL; 20 t ha ?1 ), (ii) NPKS nutrients (iii) model carbon (MOC) equivalent amounts total contained PL, (iv) + MOC. Control (no amendments) gypsum (5 ) included district practices. Before planting, applied vertical band at – 40 cm depth pre-incubated. Plant biomass, grain yield, root properties soil associated amendment quantified harvest. Results Compared control, was increased 30% 43% MOC, 61% NPKS, but no differences detected MOC gypsum. The lower increase PL than without due readily available form inorganic fertilisers vs slower mineralisation Improvement alkaline resulted proliferation use. Grain showed positive correlation biomass layers. Conclusions short-term (one crop cycle), improved soil’s physical chemical had additional effect on compared fertiliser application. Longer-term studies needed determine legacy contribution conjunction structure OAs subsoils.