Contents Soil Factors of soil formation Factors controlling the rate of soil formation Geology Rock type Rock structure Climate Soil profile Soil conservation and its types Farmland Conservation Conservation Tillage Counter Bunding Cover Crops Methods of Soil Conservation World Wide organizations for soil conservation Soil Science Society of Pakistan (SSSP)
Soil Soil is defined as the top layer of the earth’s crust. Formed by mineral particles, organic matter, water, air and living organisms. It is in fact an extremely complex, variable and living medium. Soil has a role as a habitat and gene pool, serves as a platform for human activities, landscape and heritage and acts as a provider of raw materials. These functions are worthy of protection because of their socio-economic as well as environmental importance
Factors of Soil formation Parent material Geologic material in which a soil forms. Climate Through effects of precipitation and temperature, climate affects the rates of biological l, chemical and physical processes involved in soil formation. Organisms Living organisms are responsible for accumulation of organic matter, nutrient cycling and profile mixing. Topography Landscape relief modifies the effects of organisms and climate on soil development. Time Effects of climate and living organisms, modified by topography, on the development of soil from parent material takes time. Effect of time can be seen by looking at chronosequences in Mississippi and Red River alluvium.
Factors controlling the rate of soilformation Geology The local geology and its interaction with climate largely determines the nature and type of soil that occurs at ground surface. Rock type Igneous Sedimentary Metamorphic Rock structure The rock structure is the result of processes that have impacted on the rock after deposition Climate Climate is of considerable influence to erosional and weathering processes
Soil profile• Soil formation begins first withthe break down of rock intoregolith. Continued weatheringand soil horizon developmentprocess leads to the developmentof a soil profile, the verticaldisplay of soil horizons.
Horizons of Soil O Horizon At the top of the profile is the O horizon. The O horizon is primarily composed of organic matter. A Horizon The A horizon marks the beginning of the true mineral soil. In this horizon organic material mixes with inorganic products of weathering. The A horizon typically is dark colored horizon due to the presence organic matter. E Horizon The E horizon generally is a light-colored horizon with eluviation being the dominant process. Leaching, or the removal of clay particles, organic matter, and/or oxides of iron and aluminum is active in this horizon. B Horizon The B horizon is a zone of illuviation where downward moving, especially fine material, is accumulated. The accumulation of fine material leads to the creation of a dense layer in the soil. C Horizon The C horizon represents the soil parent material, either created in situ or transported into its present location. Beneath the C horizon lies bedrock.
Soil conservation Soil conservation is a set of management strategies for prevention of soil being eroded from the Earth’s surface or becoming chemically altered by overuse, acidification, salinization or other chemical soil contamination. Following are the types of soil conservation: Farmland conservation Conservation Tillage Contour Bunding and Bench Terracing Cover Crops
Farmland conservation Farmland conservation techniques such as contour planting, crop rotation and strip planting re-energize soil content and prevent erosion.
Conservation Tillage Conservation tillage practices like strip-tilling, no-tilling, ridge-tilling and mulch-tilling leave a good portion of nutrient-rich organic material in place and conserve topsoil.
Contour bunding Contour bunding and bench terracing are effective soil conservation techniques. Bunding protects land from water runoff, and bench terracing recycles organic matter from one terrace to the next.
Cover Crops Planting cover crops like oats, wheat or rye on unused land builds organic matter while protecting topsoil from wind and water erosion.
Methods of Soil Conservation Tree plantation Terracing Contour ploughing Crop rotation No-till farming Watering PH maintenance Soil organisms Planting of Indigenous crops
World Wide organizations for soil conservation World Association of Soil and Water Conservation (WASWC) International Soil Conservation Organisation (ISCO) Soil and Water Conservation Society (SWCS) 1943
Soil Science Society of Pakistan (SSSP) The Soil Science Society of Pakistan (SSSP) is a non- government and non-profit organization of scientists, engineers, technologists and students involved in the profession of Soil Science. The Society, established in 1958, was revived in 1984. Active members of the Society are over 400.