solul

Solul is the Romanian term for soil, the outermost natural layer of the Earth’s crust that supports plant life. In geology and agronomy, solul is understood as a natural medium composed of mineral particles, organic matter, water, and air, continually shaped by weathering, biological activity, and climate.

Its texture—ranging from sandy to clayey—and its structure influence porosity, water retention, and root penetration. The typical composition is minerals, organic matter, water, and air, with organic matter providing nutrients and beneficial organisms. The pH, cation exchange capacity, and salinity affect nutrient availability and plant growth. Soil health is often assessed through fertility, structure, moisture regime, and biological activity.

Solul forms in layers called horizons. The O horizon contains decomposed litter; the A horizon (topsoil) mixes minerals with organic matter; the B horizon accumulates materials leached from above; the C horizon lies closer to the parent material and is less affected by soil-forming processes. Over time, horizons develop under the influence of climate, organisms, relief, and time.

Soil types are classified by texture, fertility, and pH. In agronomy, loam is frequently cited as a balanced texture for cultivation. International systems such as FAO and USDA provide standardized classifications; Romanian practice often combines global methods with local soil maps and agricultural data.

Solul quality is essential for agriculture, ecosystem services, and water regulation. Erosion, compaction, salinization, and contamination reduce productivity. Management practices include crop rotation, cover crops, reduced tillage, organic amendments, and erosion control to maintain structure, fertility, and resilience.

See also: soil science, pedology, soil profile, soil fertility, land use.