How does organic matter protect soil?

The answer

Organic matter helps bind mineral particles into stable aggregates, stores and slowly releases nutrients, holds water and feeds soil organisms. Soils richer in organic matter generally resist erosion and compaction better and cope better with drought. Because it builds slowly and is lost quickly, protecting it is a priority: intensive tillage, bare ground, burning residues and erosion all deplete it, while roots, residues, compost and cover crops rebuild it. Expect gains over years, not weeks.