About

Soil texture is an immutable property determined by the relative proportions of sand, silt, and clay particles. It dictates the physical behavior of the soil, specifically its ability to hold water (retention) and its hydraulic conductivity (drainage). Accurately classifying soil texture is the first step in irrigation design and foundational selection.

This analyzer digitizes the USDA Soil Texture Triangle logic. By inputting particle size analysis data, users can determine if their site consists of heavy clay, which is prone to compaction and waterlogging, or sandy loam, which drains rapidly but struggles with nutrient retention. The output provides specific management protocols for each class to optimize plant health.

Formulas

The validity of the sample requires the summation of all particle fractions to equal unity:

P_sand + P_silt + P_clay = 100%

Logic relies on boundary inequalities. For example, a sample is Clay if:

P_clay ≥ 40 ∧ P_sand ≤ 45 ∧ P_silt < 40

Reference Data

Texture Class	Infiltration Rate (mm/hr)	Water Holding Capacity	Compaction Risk	Nutrient Retention
Sand	> 50	Very Low	Low	Very Low
Loamy Sand	25 − 50	Low	Low	Low
Sandy Loam	15 − 25	Low-Moderate	Moderate	Moderate
Loam	10 − 15	High	Moderate	High
Silt Loam	8 − 12	Very High	High (Surface Crust)	High
Sandy Clay Loam	5 − 10	Moderate	Moderate	Moderate
Clay Loam	2 − 5	High	High	High
Silty Clay	1 − 4	High	Very High	High
Clay	< 1	Very High	Extreme	Very High

Frequently Asked Questions

Soil texture analysis measures the mineral fraction of the soil only. Organic matter, water, and air are excluded from the calculation. The relative percentages of the three mineral sizes (Sand, Silt, Clay) represent the whole of the texture sample.

Sandy Clay contains more abrasive silica particles, making it slightly easier to till than Clay Loam, but it drains faster. Clay Loam holds nutrients better but is more prone to becoming "sticky" and unworkable when wet.

Changing texture is physically impossible on a large scale as it requires replacing the mineral base. However, adding organic matter (compost) improves the structure, making Clay drain better and Sand hold more water, effectively mitigating the downsides of the texture.

Loam is universally considered ideal because it balances drainage and retention. Sandy Loam is preferred for root crops (carrots, potatoes) as it offers less resistance to expansion.