Experimental insights into mucilage-mediated nutrient diffusion in different soil textures

Background and Aims Volumetric soil water content ( θ ᵥ θ v ) strongly regulates nutrient diffusion, particularly under drying conditions. This study investigates how plant-derived mucilage alters water retention and the effective diffusion coefficient ( Dₛ D s ) of calcium (Ca 2 ⁺) in soils with contrasting textures (sand, sandy loam, and loam) under varying θ ᵥ θ v . Methods We amended soils with maize mucilage at contents ( Cₘ C m ) of 0.0, 2.5, 5.0, and 7.5 mg/g adjusted them to three θ ᵥ θ v levels. A 45 Ca tracer and phosphor imaging were used to track Ca 2 ⁺ diffusion over time. Dₛ D s was estimated from the 45 Ca distribution, allowing evaluation of mucilage effects on water retention and solute transport. Results Mucilage effects were strongly texture- and θ ᵥ θ v -dependent. In loam, mucilage enhanced θ ᵥ θ v and Dₛ D s at the same soil matric potential ( ψ ₛₒᵢₗ ψ soil ); for example, at a θ ᵥ θ v of 0.125 cm 3 /cm 3 ( ψ ₛₒᵢₗ ψ soil = $$-$$ - 23,608 cm), Dₛ D s increased by more than eightfold at the $${