SOIL DEGRADATION Impacting The Environment Mr. Stewart

WHAT IS SOIL?

SOIL  Soil is the earth’s fragile skin that anchors all life on Earth. It is comprised of countless species that create a dynamic and complex ecosystem and is among the most precious resources to humans.  Soil is the end product of the influence of the climate, relief (elevation, orientation, and slope of terrain), biotic activities (organisms), and parent materials (original minerals) acting over periods of time.

SOIL PROFILE

IDENTIFY

WHAT IS SOIL DEGRADATION?

SOIL DEGRADATION  Soil degradation may be viewed as any change or disturbance to the soil perceived to be deleterious or undesirable.  Soil Degradation are broken down to  One (Physical)  Two (Chemical)  Three (Biological) subgroups

SOIL DEGRADATION

WHAT IS SOIL COMPACTION?

SOIL COMPACTION  Soil compaction is the process in which a stress applied to a soil causes densification as air is displaced from the pores between the soil grains. When stress is applied that causes densification due to water (or other liquid) being displaced from between the soil grains then consolidation.

DENSIFICATION

SOIL COMPACTION  Soil compaction is usually a combination of both engineering compaction and consolidation, so may occur due to a lack of water in the soil, the applied stress being internal suction due to water evaporation as well as due to passage of animal feet and other factors such as heavy machinery.

COMPACTING METHODS  Static - a large stress is slowly applied to the soil and then released.  Impact - the stress is applied by dropping a large mass onto the surface of the soil.  Vibrating - a stress is applied repeatedly and rapidly via a mechanically driven plate or hammer. Often combined with rolling compaction (see below).  Gyrating - a static stress is applied and maintained in one direction while the soil is a subjected to a gyratory motion about the axis of static loading. Limited to laboratory applications.  Rolling - a heavy cylinder is rolled over the surface of the soil. Commonly used on sports pitches. Roller-compactors are often fitted with vibratory devices to enhance their ability.  Kneading - shear is applied by alternating movement in adjacent positions. An example, combined with rolling compaction, is the 'sheepsfoot' roller used in waste compaction at landfills.

MEASURED  A soil penetrometer can be used as a diagnostic tool to measure the extent and depth of subsurface soil compaction.

PENETROMETER

TIRE COMPACTION

COMPACTION

ADVANTAGE  Roads  Housing  Lawns

DISADVANTAGES  Causes soil pore spaces to become smaller  reduces water infiltration rate into soil  Decreases the rate that water will penetrate into the soil root zone and subsoil  Increases the potential for surface water ponding, water runoff, surface soil waterlogging and soil erosion  Reduces the ability of a soil to hold water and air, which are necessary for plant root growth and function  Reduces crop emergence as a result of soil crusting  Impedes root growth and limits the volume of soil explored by roots  limits soil exploration by roots and decreases the ability of crops to take up nutrients and water efficiently from soil  Reduces crop yield potential

MANAGEMENT  Traffic control -Reduce overall soil compaction in a field -Improve soil structure -Increase water infiltration -Increase soil water storage -Increase moisture use efficiency -Improve nutrient use efficiency

MANAGEMENT  Crop rotation -Promote plant roots to grow through and break up compacted soils -Increase soil organic matter -Improve soil structure, improve water infiltration and penetration into soil -Promote biological diversity

WHAT IS WATERLOGGING

WATER LOGGING  Waterlogging refers to the saturation of soil with water. Soil may be regarded as waterlogged when the water table of the groundwater is too high to conveniently permit an anticipated activity, like agriculture.

WATER LOGGING

ADVANTAGES  Planting of WATER LOVING plants.  Rearing of aquaculture  Irrigation method

DISADVANTAGE  Insect harboring

DISADVANTAGE  Flooding

ADVANTAGE  Hinder of Agriculture

DISADVANTAGE  LEACHING  Damaging of plant roots

MANAGEMENT  Consider a drainage  Choice of crop  Fertilizer  Weed control  Proper farming planning

ACIDIFICATION

SOIL ACIDIFICATION  Soil acidification is the buildup of hydrogen cations, also called protons, reducing the soil pH. This happens when a proton donor is added to the soil. The donor can be an acid, such as nitric acid and sulfuric acid (these acids are common components of acid rain). It can also be a compound such as aluminium sulfate, which reacts in the soil to release protons. Many nitrogen compounds, which are added as fertilizer, also acidify soil over the long term because they produce nitrous and nitric acid when oxidized in the process of nitrification.

SOIL ACIDIFICATION

SYMPTOMS  Reducing Yield  Stunted root growth  Abnormal leaf color  Poor nodulation of legumes

BENEFITS  Raises soil pH. A well balanced soil pH is important for: soil fertility and nutrient availability plant species that can be grown biological activity of the soil

BENEFITS  Livestock health Increased calcium and magnesium levels in the plant helps to overcome problems such as grass tetany in cattle.

BENEFITS  Economics Research data shows that responses to lime can be profitable