Effect of Maize Mucilage on Soil Nutrient Transport

Soil water conditions crucially influence plant nutrient uptake, especially when dry conditions limit nutrient diffusion in soil. Recently Chia seed mucilage has been shown to enhance nutrient transport by augmenting soil water-holding capacity, reducing liquid phase tension, and increasing viscosity. However, the impact of plant mucilage on nutrient diffusion in different soils and moisture levels remains to be determined. In this study, we assessed maize root-derived mucilage effects on calcium (Ca) diffusivity in soils with varying textures (sand, sandy loam, loam) and moisture levels (25, 15, 7.5%). 45Ca was used as a tracer for the diffusion of nutrients within soils. The soils were adjusted to the desired water contents using either distilled water or a solution of 60 mM 45CaCl2. Then, soil wetted with distilled water was packed into the first half part of the containers with a size of 5x1x0.3 cm, and the other half was packed with soils wetted with 45CaCl2. Over 65 days, digital autoradiography was employed to trace the diffusion of 45Ca within the soil. A 1D diffusion equation was employed to simulate the transport of Ca within the soil by inversely adjusting the diffusion coefficient of the soil. Our findings revealed that mucilage significantly influenced soil diffusivity, contingent on content, soil texture, and moisture levels. Higher mucilage concentration initially delayed 45Ca diffusivity, especially in finer textures probably due to the gel's viscosity. However, it prevented a significant drop in diffusion rate in drier conditions, resulting in higher 45Ca diffusivity compared to control soils. In summary, maize mucilage improved the diffusivity of Ca in dry conditions by maintaining the continuity of the liquid phase.