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Transcript
The Importance of Soil Original by Nancy Williams Modified by Georgia Agricultural Education Curriculum Office July, 2002 August 2008 The Importance of Soil • The history of soil – Dates back all the way to the Egyptians civilization of 4,000 years ago – Recently in the US history supplies another example of soil misuse. This is with the Dust bowl of the 1930’s. – The Dust bowl was a drought that misused the soil in having wind erosion. August 2008 The Importance of Soil • Additional acreage is lost due to urbanization or degradation . • Soil is a nonrenewable resource August 2008 The Importance of Soil • Most of the time we take soil for granted. • Soil is a very thin and often fragile layer of life supporting material. August 2008 The Importance of Soil • Facts about the earth – Earth consists of solid part (core, mantle, and crust) and the atmosphere surrounding it. – Most of the earth is covered by sea – Where continents exist the crust is thicker – This is usually about 50 miles thick August 2008 The Importance of Soil • The atmosphere is about 170 miles deep. • The soil forms a very thin interface between the two. August 2008 The Importance of Soil • What does living things need? – Proper temperature – Oxygen – Water – Carbon – Other nutrients – These factors are exchanged in the soil that allow elements to be recycled rather than lost August 2008 The Importance of Soil • Oxygen: – Plant roots need oxygen to grow. – Gases will pass in and out of the soil to supply the oxygen for the roots August 2008 The Importance of Soil – Temperature • Plants will grow best in certain soil temperature ranges. • Most plants will root in temperature around 40-50 degrees F. • Water: – Seldom stays in one place August 2008 The Importance of Soil • Carbon: – Plant leaves collect sunlight to use the energy in the process of photosynthesis. – Which involves converting atmosphere carbon to biological carbon – Atmosphere carbon = carbon dioxide – Biological carbon = simple sugars August 2008 The Importance of Soil • Nutrients : – Plant nutrients are chemicals a plant needs to grow. – There are two types of nutrients cycles • Nitrogen cycle • Mineral cycle August 2008 The Importance of Soil • Nitrogen: – Comes directly from the atmosphere where it occurs as a gas that plants cannot use. August 2008 4 Needs of Soil • There are four needs of the soil – Anchorage – Water – Oxygen – Nutrients August 2008 4 Needs of Soil • Anchorage: – This is where plants grow freely and are firmly supported or anchored so they can grow to reach the sunlight. – Water: – Soil will provide the plants with all the water the plant needs – Roots are the best water absorbing body . August 2008 4 Needs of Soil • Oxygen: – Call creature even plants need oxygen. Plants release oxygen during photosynthesis but consume it during respiration. August 2008 4 Needs of Soil • Nutrients: – There are 16 nutrients usually considered to be needed for plants. – Plants obtain 13 of the 16 nutrients from the soil itself. – Other nutrients come from Air and water. • Carbon • Oxygen • hydrogen August 2008 3 phase system • What is soil Matrix? – It is the arrangement of solid particles and pore spaces which consists of three phases of solid , liquid, and gases. August 2008 3 phase system • The ideal Soil Type: – 50% solid material – 45 % mineral particles – 5% organic matter – 25% water – 25% gases August 2008 3 phase system • Root Growth: – Water reaches the root by two ways • Either water flows toward the root • Or the root grows into moist soil August 2008 Ag Uses of Soil • Humans depend on soil to grow food, fiber, timber, and ornamental plants. • Most Ag uses require different soil types and management practices August 2008 4 Types of Ag Uses • 1. Cropland: – Cropland is land which soil is worked and crops are planted, cared for, and harvested. – Crops that are grown • Annual crops are corn and soybeans • Fiber crops are cotton horticultural crops like vegetables. August 2008 4 Types of Ag Uses • Annual Crops: – Require yearly soil preparation – Perennial Forages: – Are alfalfa. – Which are crops that are in the ground for a few years – These crops keeps the soil completely cover and keeps the soil in place. August 2008 4 Types of Ag Uses • Perennial Hort. crops: – This includes fruits, nuts, and nursery stock August 2008 4 Types of Ag Uses • 2. Grazing Land: – Much of the land in the US is grazed by cattle and sheep August 2008 4 Types of Ag Uses • 3. Forest – Foresters probably disturb soil the least, – 4. Other Uses – This usually deals with growing plants in tiny pots and usually with Landscapers August 2008 Non Ag Uses of Soil • A few of the Non Ag uses of soil are: – Recreation – Foundations – Waste Disposal – Building Materials August 2008 Non Ag Uses of Soil • Recreation: – Recreational uses of the soil can be: • Sitting in a urban park and seeing kids play on the playground, softball diamond, • They can also be golf courses, campgrounds. • Most demanding recreational use is the use of playing fields. As most of the time there is a demand to have good grow on turf that can with stand about anything. August 2008 Non Ag Uses of Soil • Foundations: – A good builder usually will have the soil tested to a dept of several feet. – The structural soundness of a building depends on the amount of soil that is under the building. August 2008 Land Uses in the US • • • • • • • 27% is in rangeland 26% is in cropland 27% is in forestland 2% is in conservation reserve land 4% is in other land 6% is in urban land 8% is in pastureland August 2008