Step on it and you barely notice. But soil holds the roots that feed the world, filters the water we drink, and stores more carbon than the atmosphere and all plants combined. It forms over centuries as rock weathers, plants decay, and organisms break material down.

A healthy soil contains minerals, organic matter, water, air, and living creatures in proportions that vary by location and management. Farmers can influence all of them. Compaction squeezes out air. Erosion strips away the richest layers. Organic matter declines when fields are tilled relentlessly.

Main soil components

• Mineral particles of sand, silt, and clay
• Organic matter from decomposed plant and animal material
• Pore spaces holding water and air
• Living organisms including bacteria, fungi, and earthworms

Soil is not renewable on a human timescale. Losing an inch to erosion can take decades or more to rebuild naturally, which is why conservation practices matter to the long-term productivity of any farm.