Human Activities Affecting Soil Quality and Quantity PDF

Learning Objectives Identify human activities such as farming, construction of structures, and waste disposal that affect the quality and quantity of soil Give ways of conserving and protecting the soil for future generations SOIL RESOURCES  SOIL - is formed b...

Learning Objectives Identify human activities such as farming, construction of structures, and waste disposal that affect the quality and quantity of soil Give ways of conserving and protecting the soil for future generations SOIL RESOURCES  SOIL - is formed by the interaction of the parent material (bedrock), climate, time, plants and animals, and topography. - it consists of minerals, organic matter, water, and air.  SOIL - it supports the growth of plant. - one of its characteristic features is the texture. - Texture- refers to the proportions of particles with different sizes.  Types of Soil 1. clay 2. silt 3. sand 4. loam Types of Soil (Sand)  Types of Soil (Sand) It is most extensively used construction material. It consists of particles of rock and hard minerals, such as silicon dioxide.  Types of Soil (Sand) They are the largest type of soil particles, where each particle is visible to naked eye.  Types of Soil (Sand) The large, relatively stable sand- particle size increases soil aeration, improves drainage in tight soils and creates plant-growth supporting qualities, or tilt. Types of Soil (Silt)  Types of Soil (Silt) Silt is a sediment material with an intermediate size between sand and clay. Carried by water during flood it forms a fertile deposit on valleys floor.  Types of Soil (Silt) Silt is a non-plastic or low plasticity material due to its fineness. Due to its fineness, when wet it becomes a smooth mud that you can form easily into balls or other shapes in your hand and when silt  Types of Soil (Silt) soil is very wet, it blends seamlessly with water to form fine, runny puddles of mud. Types of Soil (Clay)  Types of Soil (Clay) Clay particles are the finest of all the soil particles, measuring fewer than 0.002 mm in size. It consists of microscopic and sub- microscopic particles derived from the chemical decomposition of rocks.  Types of Soil (Clay) Clay is a fine grained cohesive soil. They stick together readily and form a sticky or gluey texture when they are wet or dry.  Types of Soil (Clay) Clay is made of over 25 percent clay, and because of the spaces found between clay particles, clay soils hold a high amount of water. Clay expand when in contact with water and shrink when getting dry.  Types of Soil (Clay) Compared to sand particles, which are generally round, clay particles are thin, flat and covered with tiny plates.  Types of Soil (Clay) Organic clay is highly compressible and its strength is very high when dry, which is why it is used in construction as mud mortar. Types of Soil (Loam)  Types of Soil (Loam) The way the other particles combine in the soil makes the loam. For instance, a soil that is 30 per cent clay, 50 per cent sand and 20 per cent silt is a sandy clay loam,  Types of Soil (Loam) with the soil types before “loam” listed in the order their particles are most dominant in the loam.  Types of Soil (Loam) The labels “clay loam,” “silt loam” and “sand loam” are used to refer to soils that are composed predominantly of those ingredients.  Soil Profile - is the arrangement of soil horizon. - the extent and development of soil profile vary depending on different environments.  Soil Profile 1. 0 horizon- consists largely of organic matter at various stages of decomposition. - the partly-decomposed organic matter is called humus. - It also includes bacteria, algae, and insect.  Soil Profile 2. A horizon- consists of minerals and humus. - O and A horizons make up the top soil. 3. E horizon- is a light colored layer that contains little organic material.  Soil Profile - It is the zone of eluviation and leaching. Eluviation- is the washing of the fine components. Leaching- is the depletion of soluble materials.  Soil Profile 4. B horizon- is the zone of accumulation, it is also called subsoil. -Horizon O, A, E and B constitute the “true soil” or solum.  Soil Profile 5. C horizon- is characterized by partially- altered parent material. 6. R horizon – (bedrock) a mass of rock such as granite, basalt, quartzite, limestone or sandstone that forms the parent material for some soils  Soil Profile - One-third of the Earth’s surface is covered with land. Arable land- refers to lands that are temporarily used for agricultural crops, temporary meadows for moving or pasture, and temporary fallow lands.  Soil Profile Non- arable land- includes orchard lands, vineyards, coffee plantation, rubber plantation, and nut plantation, as well as lands used for pasture and grazing, and those land unsuited for any agricultural use.  Human activities that affect the quantity and quality of soil 1. Human- induced erosion - is a result of excessive farming, logging, overgrazing, fires, and improper irrigation.  Human activities that affect the quantity and quality of soil 2. Desertification- which occurs when a non- desert area exhibits the characteristics of a true desert, is due to land mismanagement such as deforestation, slash-and-burn agriculture, and overgrazing.  Human activities that affect the quantity and quality of soil 3. Desalination- the concentration of salts on the surface or near the surface of the soils, happens when there is large-scale irrigation that leaves dissolved salts when water evaporates, preventing the uptake of water by the roots of the plants.