Soil Analysis Section (2) PDF

# PLANT ECOLOGY ## SOIL ANALYSIS ### SECTION (2) ### MOHAMMED HANAFY ## 5 - Capillary Rise Of Water * Capillary: the action by which water is raised or lowered relative to the water table. * Pores in the soil act as *capillary tubes* which help in the movement of water upward. A picture...

# PLANT ECOLOGY ## SOIL ANALYSIS ### SECTION (2) ### MOHAMMED HANAFY ## 5 - Capillary Rise Of Water * Capillary: the action by which water is raised or lowered relative to the water table. * Pores in the soil act as *capillary tubes* which help in the movement of water upward. A picture depicting a narrow glass tube filled with water, the water level in the tube being just above the water table outside of the tube. An arrow depicting the water being drawn upwards in the tube. * If we placed dry soil in contact with water Table: * Initial water will be " chemically" bounded to the soil matrix. * Subsequent water will be " cohesively " bounded through hydrogen bonding to the chemically bounded water. * So we will found that water rises into the dry soil from water table until occurrence of "Balance" between gravitational pull on the mass of water and attraction force of the soil solids for the water. * To explain this more clearly, let us do this experiment ### Procedures: * Prepare two glass tubes with two holes. * Close one end of each tube with muslin membrane. * Fill one tube of sandy soil and the other with clay soil, and immerse it in water. ### Observation: * After one hour: hight of water in sandy soil more than clay. * After 12 hours: hight of water in clay more than sandy soil. A picture showing two tubes filled with different soils (sand, clay, loam). The water level in each of the tubes is different. * Comment: ### Sandy soil has: * Large particles, and large spaces between particles. * Small attractions force between particles. * SO, Sandy soil absorb water rapidly and lose it rapidly. ### Clay soil has: * Small particles, and small spaces between particles. * High attractions force between particles. * SO, Clay soil absorbs water slowly and lose it slowly. A picture showing two circles representing sandy soil and clay soil. The sandy soil circle is filled with a lot of small dots, representing sand particles, with large spaces between them. The clay soil circle is filled with many dots almost touching each other, showing very little spaces between particles. ## Determination of soil texture: * As we taught before, soil texture: is the relative proportion of different size particles "sand, silt and clay " in the soil. * How can we determine it? 1. By hydrometer: (للمعرفة فقط) An instrument we use it to record time of precipitating each component of the soil. A picture showing a hydrometer being submerged in a jar filled with a brown solution. 2. Sieves method: * We place 100 gm of soil in the top of arranged seives"where largest diameter in the top and gradually decrease diameter till the bottom where the smallest diameter is found" * Then; we use sieve shaker to shake the sieves. Then we calculate the weight of each soil component(soil fraction). * Then; we calculate the relative percentage by dividing weight of component to the total weight of the soil and times it by 100. The last step, we represent ratios on soil texture triangle by straight lines, the point at which the three lines intersect represent soil texture of the tested soil. A picture showing a stack of sieves with different mesh sizes. ## The soil textural triangle: * There are 12 soil regions. * Each texture is corresponding to specific percent of sand, silt and clay. * The name of the compartment in which the three lines intersect is the class name of the soil. * Knowing the soil texture helps in managing soil. A picture showing a soil texture triangle, showing the soil regions and the percentages of sand, silt and clay, for each region. * There are three rules to draw lines on soil texture triangle: 1. must be straight line 2. parallel to one of two other sides of the triangle 3. head of the formed angle equal 100 of component that you draw. A picture showing a soil texture triangle, showing the soil regions and the percentages of sand, silt and clay, for each region. * Example: | Sand | Silt | Clay | | ----- | ---- | ----- | | 50% | 25% | 25% | -Therefore, The Soil Texture is "Sandy clay loam." A picture showing a soil texture triangle and the soil regions where sand = 50%, silt = 25%, and clay = 25% ## تم بفضل الله تعالي - A picture showing a small green plant growing from the ground and the words "تم بفضل الله تعالي -" at the top of the image.