Final answer:
A gritty texture in a soil assessment indicates the presence of sand in the soil. Sand is a larger particle that contributes to a coarse soil texture and different water retention properties when compared to finer particles like clay and silt.
Step-by-step explanation:
If a soil feels gritty when doing a "feel" assessment of texture, then an appreciable amount of sand is present. Soil texture is influenced by the sizes of particles that make up the soil, with sand being the coarsest of textures that can be felt by touch.
Soil consists of a mixture of components including inorganic mineral matter, organic matter, water, and air. The inorganic mineral fraction is a combination of different sized particles: clay, silt, and sand, with sand particles being larger and creating a gritty texture. The presence of larger particles, like sand, affects the soil's ability to hold water, with sandy soils having fewer but larger spaces for water compared to clay soils, which have many small spaces.
Soil composition is also affected by biological factors like plants and microorganisms that can alter its structure, and by physical and chemical weathering that produces rock fragments in soils. The mixture of these elements and the resulting texture affect soil's capacity to support plant life.