Soil Textural Triangle Calculator

Soil Textural Triangle Calculator

function calculateSoilTexture() { var sand = parseFloat(document.getElementById("sandPercentage").value); var silt = parseFloat(document.getElementById("siltPercentage").value); var clay = parseFloat(document.getElementById("clayPercentage").value); var resultDiv = document.getElementById("result"); if (isNaN(sand) || isNaN(silt) || isNaN(clay) || sand < 0 || silt < 0 || clay < 0) { resultDiv.innerHTML = "Please enter valid, non-negative numbers for all percentages."; return; } var sum = sand + silt + clay; if (Math.abs(sum – 100) > 0.1) { // Allow for slight floating point errors resultDiv.innerHTML = "Error: The sum of Sand, Silt, and Clay percentages must be 100%. Current sum: " + sum.toFixed(1) + "%."; return; } var soilTexture = classifySoil(sand, silt, clay); resultDiv.innerHTML = "The soil texture is: " + soilTexture + ""; } function classifySoil(S, I, C) { // USDA Soil Textural Triangle Classification Logic // Order of checks is important to avoid misclassification due to overlapping conditions. // 1. Clay if (C >= 40) { if (S >= 45) return "Sandy Clay"; if (I >= 40) return "Silty Clay"; return "Clay"; } // 2. Silty Clay Loam // C between 27 and 40, I >= 40 if (I >= 40 && C >= 27) return "Silty Clay Loam"; // 3. Sandy Clay Loam // C between 20 and 40, S >= 45 if (S >= 45 && C >= 20) return "Sandy Clay Loam"; // 4. Clay Loam // C between 20 and 40, and not covered by Silty/Sandy Clay Loam if (C >= 20 && C < 40) { // At this point, we know S < 45 and I = 80 && C = 50, C < 27 (and S = 50 && C = 85) return "Sand"; // 8. Loamy Sand if (S >= 70 && C = 45, C < 20 (and I = 45 && C < 20) return "Sandy Loam"; // 10. Loam // This is the central region, if none of the above conditions are met. // It implies C < 20, S < 45, I < 50. return "Loam"; }

Understanding the Soil Textural Triangle

Soil texture is one of the most fundamental physical properties of soil, influencing everything from water retention and nutrient availability to aeration and workability. It refers to the relative proportions of sand, silt, and clay particles in a soil sample. These three particle sizes are the primary components that determine a soil's textural class.

The Three Soil Separates: Sand, Silt, and Clay

• Sand: These are the largest soil particles, ranging from 0.05 to 2.0 mm in diameter. Sandy soils feel gritty, drain quickly, and have good aeration but poor water and nutrient retention.
• Silt: Silt particles are intermediate in size, between 0.002 and 0.05 mm. Silty soils feel smooth or floury, have moderate water retention, and are generally fertile.
• Clay: Clay particles are the smallest, less than 0.002 mm in diameter. Clayey soils feel sticky when wet, have high water and nutrient retention, but can be poorly aerated and difficult to work when compacted.

What is a Soil Textural Triangle?

The Soil Textural Triangle is a graphical tool used by soil scientists, farmers, and engineers to classify soil samples based on their sand, silt, and clay content. Developed by the USDA (United States Department of Agriculture), it's a ternary plot where each side represents the percentage of one of the three soil separates. The sum of the percentages of sand, silt, and clay in any given soil sample must always equal 100%.

By plotting the intersection of the three percentages on the triangle, one can determine the soil's textural class, such as "Loam," "Sandy Loam," "Clay," or "Silty Clay Loam." There are 12 basic textural classes, each with distinct properties and implications for land use and management.

Why is Soil Texture Important?

Knowing your soil's textural class is crucial for several reasons:

• Agriculture: It dictates irrigation needs, fertilizer application rates, and crop suitability. For example, sandy soils require more frequent watering, while clay soils can hold more nutrients.
• Engineering: Soil texture affects foundation design, road construction, and erosion control.
• Environmental Science: It influences pollutant movement, water infiltration rates, and habitat suitability for various organisms.
• Gardening: Home gardeners can use this information to amend their soil appropriately, improving drainage, water retention, or nutrient holding capacity.

How to Use the Soil Textural Triangle Calculator

Our Soil Textural Triangle Calculator simplifies the classification process. Instead of manually plotting points on a diagram, you simply input the percentage of sand, silt, and clay from your soil analysis. Here's how:

1. Obtain Soil Analysis: You'll need a laboratory soil test that provides the percentage breakdown of sand, silt, and clay.
2. Enter Percentages: Input the percentage values for Sand, Silt, and Clay into the respective fields in the calculator.
3. Ensure Sum is 100%: The calculator will automatically check if your entered percentages sum up to 100%. If they don't, it will prompt you to adjust them, as this is a fundamental rule of the textural triangle.
4. Calculate: Click the "Calculate Soil Texture" button.
5. View Result: The calculator will instantly display the USDA soil textural class for your sample.

Example Calculation:

Let's say your soil analysis reveals the following composition:

• Sand: 40%
• Silt: 40%
• Clay: 20%

When you input these values into the calculator:

1. Enter 40 in "Percentage Sand (%)".
2. Enter 40 in "Percentage Silt (%)".
3. Enter 20 in "Percentage Clay (%)".
4. Click "Calculate Soil Texture".

The calculator will output: "The soil texture is: Loam". This is a common and highly desirable soil type, often considered ideal for agriculture due to its balanced properties.

Use this calculator to quickly and accurately determine your soil's textural class, providing valuable insights for better land management and planning.