how big is the rhizosphere

The rhizosphere typically extends 1–5 mm from the root surface, though its functional range may vary based on root architecture, plant type, and soil texture. Its size isn’t fixed but defined by biological gradients such as nutrient concentration, microbial density, and root exudate diffusion. In some cases, fungal hyphae can extend the rhizosphere’s influence several centimeters beyond the root zone.