Explain under what circumstances earthworm channels might increase downward saturated water flow, but not have much effect on the leaching of soluble chemicals applied to the soil.

Answer: soul formation is a critical on soil fertility, Earth worm improves soul, through humus formation, earthworm contribute to soil structure. Porosity and structural stability and reduces run-off. Earthworm modifies nutrient cycling and soil organic matter. it induce substance that improves plant health and growth.

Earthwormth changes the soil structure, nutrient and water. cultural practices like tillage and organic matter regulate the size and activities of the earthworm community.