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Determining Soil Texture by Feel Edwin L University of Kentucky UKnowledge Agriculture and Natural Resources Publications Cooperative Extension Service 1-2015 Determining Soil Texture by Feel Edwin L. Ritchey University of Kentucky, [email protected] Joshua M. McGrath University of Kentucky, [email protected] David Gehring Natural Resources Conservation Services Click here to let us know how access to this document benefits oy u. Follow this and additional works at: https://uknowledge.uky.edu/anr_reports Part of the Agriculture Commons, and the Environmental Sciences Commons Repository Citation Ritchey, Edwin L.; McGrath, Joshua M.; and Gehring, David, "Determining Soil Texture by Feel" (2015). Agriculture and Natural Resources Publications. 139. https://uknowledge.uky.edu/anr_reports/139 This Report is brought to you for free and open access by the Cooperative Extension Service at UKnowledge. It has been accepted for inclusion in Agriculture and Natural Resources Publications by an authorized administrator of UKnowledge. For more information, please contact [email protected]. COOPERATIVE EXTENSION SERVICE UNIVERSITY OF KENTUCKY COLLEGE OF AGRICULTURE, FOOD AND ENVIRONMENT, LEXINGTON, KY, 40546 AGR-217 Determining Soil Texture by Feel Edwin Ritchey and Josh McGrath, Plant and Soil Sciences; and David Gehring, Natural Resource Conservation Services 100 What is soil texture? Soil texture refers to the proportion Figure 1. USDA soil texture tri- 90 10 of sand, silt, and clay in a soil. Texture angle showing twelve soil texture classes based on proportion of influences almost every aspect of soil sand, silt, and clay particles. 80 20 use, both in agricultural and engineer- Coarse textured soils are tan, ing applications, and even how natural medium textured soils are ecosystems function. Many scientists green, fine textured soils 70 30 are yellow. consider soil texture the most important clay soil property as it can influence soil/water 60 40 relationships, gas exchange, and plant SILT % nutrition. Accurately determining soil 50 50 silty texture in a lab requires time and money; CLAY % clay therefore, it is often necessary to estimate 40 sandy 60 soil texture in the field by feel, which can clay clay silty clay be very accurate if done correctly. loam 30 loam 70 sandy clay What gives soil its texture? loam The three building blocks of soil— 20 loam 80 sand, silt, and clay—feel very different sandy loam silt loam and lend different properties to a soil. 10 loamy sand 90 Although the three types of soil particles silt are differentiated by their size (Table 1), sand 100 which is a physical property, the relative 100 90 80 70 60 50 40 30 20 10 amount of each of these components has SAND % a large influence on the physical, chemi- cal, and biological properties of a soil. The pore spaces between soil particles Table 1. Particle sizes for soil separates are largely responsible for the amount of How are soil textures classified? water a soil can hold. Finer soil textures Soil Separate Diameter (mm) Soils are divided into three broad texture have greater surface area, smaller soil Clay <0.002 groups—coarse-textured soils, medium- pores, and slower water infiltration into Silt 0.002 to 0.05 textured soils, and fine-textured soils the soil profile. Sand 0.05 to 2.0 (Figure 1). A coarse-textured or sandy • Sand is the largest soil particle, measur- Very fine sand 0.05 to 0.10 soil has 70 to 100 percent sand-sized ing 0.05 to 2 mm in diameter, and can Fine sand 0.10 to 0.25 particles. Because of the strong proper- be seen by the naked eye. Sand feels Medium sand 0.25 to 0.5 ties clay exhibits, a soil only needs to have gritty to the touch and holds very little Coarse sand 0.5 to 1.0 35 to 40 percent clay-sized particles to be water. Very coarse sand 1.0 to 2.0 considered fine-texturedor clayey. Finally, • Silt is the medium-sized component the medium-textured soils or loams have a of soil, measuring 0.002 to 0.05 mm more even distribution between clay and in diameter. Dry silt particles feel clay particle is 25 times smaller than sand particles. like flour or baby powder. When wet, the largest silt particle and a thousand The United States Department of silt will feel smooth. Silt only holds a times smaller than the largest sand Agriculture (USDA) soil texture triangle moderate amount of water. particle. Clay will feel sticky when (Figure 1) is used to divide soils into 12 • Clay is the smallest particle in the soil, wet and hard and brittle when dry. distinct classes based on their particle measuring less than 0.002 mm in Clay can hold much more water than size distribution, or the relative amount diameter, and can only be seen with sand or silt. In most soils, clay content of sand, silt, and clay in the soil. In the powerful microscopes. The largest increases with depth. laboratory, we would first determine the Agriculture and Natural Resources • Family and Consumer Sciences • 4-H Youth Development • Community and Economic Development EXTENSION relative amount of sand, silt, and clay accuracy, which helps identify proper excessive drainage and have good water particles in a soil sample as a percent of management practices to use. A coarse- holding capacity and nutrient retention. the sample’s weight, follow the arrows textured soil would have low water hold- Most soils can be used to produce crops from each side to where they intersect, ing capacity, high water infiltration rates, or forage, if managed properly. Accurate and identify what texture class the soil high potential for leaching, low nutrient determination of the soil texture allows belongs to. For example, if we determined retention, and should respond well to for proper management practices to that a soil had 30 percent sand, 40 percent supplemental irrigation. In contrast, be used to maximize the potential soil silt, and 30 percent clay, it would be called fine-textured soils will remain wet longer productivity. a clay loam. However, we can also esti- than medium- or coarse-textured soils, mate soil texture by feel fairly accurately have slow water infiltration rates, high References with practice. potential for denitrification, and high Thien, S.J. 1979. A flow diagram for teach- nutrient retention. The medium-texture ing texture by feel analysis. Journal of Using soil texture in the field soils, such as loams, silt loams, or clay Agronomic Education. 8:54-55. Once the soil texture is determined loams, have a good balance of sand silt, in the field, general characteristics of a and clay. Medium-textured soils gener- soil can be predicted with reasonable ally are very productive soils that allow Photos by Edwin Ritchey for sufficient water infiltration without How do I estimate texture by feel? Three simple steps along with the flow chart in Figure 2 will help you to determine soil texture by feel. Step 1: Start with a small handful of soil, Step 2: If the ball of soil stays intact, gen- Step 3: After completing the ribbon about the size of a golf ball, and slowly tly press the ball between your thumb test, add water to a pinch of soil in the add water a drop at a time, mixing as and index finger, trying to work it out to palm of your hand until you have a you go, until you have a ball of soil that form a ribbon. If you can form a ribbon, muddy puddle. Rub the mud puddle has the consistency of putty. Gently measure how long the ribbon is before against your palm and determine if it squeeze the ball to determine if it will it falls apart. feels gritty, smooth, or equally gritty stay together in a ball or fall apart. and smooth. 2 Figure 2. Flow chart to determine soil texture by feel Start with a small Adapted from S.J. Thien, 1979. A flow diagram for teaching texture handful of soil (about by feel analysis. Journal of Agronomic Education 8:54-55. the size of a golf ball). Add water slowly, mixing as you go, until the soil reaches a smooth, plastic consistency, like putty. Form the soil into a ball and squeeze. Add more dry soil, Add more water, mix thoroughly. mix thoroughly. YES YES Does YES Is the NO Is the NO the ball fall soil too soil too Sand apart? wet? dry? NO Squeeze the ball between your thumb and forenger to form a ribbon until it breaks from its own weight. GRITTY Loamy sand How Does No long is the the soil SMOOTH ribbon Silt ribbon before feel gritty? it breaks? forms GRITTY Sandy loam Excessively wet a Does Less small pinch of soil the soil EQUALLY than Loam and rub it against feel gritty? 1 inch your palm. SMOOTH Silt loam GRITTY Sandy clay loam Excessively wet a Does 1 - 2 small pinch of soil the soil EQUALLY Clay loam inches and rub it against feel gritty? your palm. SMOOTH Silty clay loam GRITTY Sandy clay Excessively wet a Does 2 inches small pinch of soil the soil EQUALLY Clay or longer and rub it against feel gritty? your palm. SMOOTH Silty clay Mention or display of a trademark, proprietary product or firm in text or figures does not constitute an endorsement and does not imply approval to the exclusion of other suitable products or firms. Educational programs of Kentucky Cooperative Extension serve all people regardless of race, color, age, sex, religion, disability, or national origin. Issued in furtherance of Coop- erative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S.
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