6 TH GRADE EARTH SCIENCE Soil Conservation

"A nation that destroys its soil destroys itself." - President Franklin D. Roosevelt, 1937 Why is soil conservation important?

The Value of Soil  A natural resource is anything in the environment that humans use.  Soil is one of the most valuable natural resources because everything that lives on land, including humans, depends directly or indirectly on soil.  Plants depend directly on soil to live and grow.  Humans and animals depend on plants-or on other animals that depend on plants-for food.

The Value of Soil  Fertile soil is valuable because there is a limited supply.  Less than one eighth of the land on Earth has soils that are well suited for farming.  Soil is also in limited supply because it takes so long to form.  It can take hundreds of years for just a few centimeters of soil to form.  The thick, fertile soil of the prairies took many thousands of years to develop.

Soil Damage and loss  The value of soil is reduced when soil loses its fertility and when topsoil is lost due to erosion.  Soil can be damaged when it loses it fertility.  Soil that has lost its fertility is said to be exhausted.  Soil in which only cotton was grown became exhausted.  This type of soil loss occurred in large parts of the South in the late 1800s.

Loss of topsoil Whenever topsoil is exposed, water and wind can quickly erode it. Plant cover can protect soil from erosion. Plants break the force of falling rain, and plant roots hold the soil together. Wind is another cause of soil loss. Wind erosion is most likely to happen in areas were farming methods are not suited to dry conditions. Wind erosion contributed to the Dust Bowl on the Great Plains.

The Problem Of Soil Erosion. Sheet erosion is the removal of the thin layer of topsoil by raindrop splash or water run- off.

The Problem Of Soil Erosion. Wind erosion is the detachment and movement of soil by wind.

Gully erosion occurs when small streams unite and create a stronger flow, cutting a channel down which water flows during or just after rain The Problem Of Soil Erosion.

Worldwide, an estimated 26 billion tons of topsoil are washed or blown off cropland each year. Every year 6 million hectares of productive dryland become desert.

Crop rotation is used to keep crops from depleting the soil. If the same crop is planted year after year, it exhausts certain nutrients in the soil. Certain crops such as legumes (soy, beans, peas, etc.) are able to replenish the nutrients. Therefore it is advisable to plant other "cover crops" maintain quality soil.

Strip Cropping is related to both contour plowing and crop rotation but has an added advantage. If a farmer were to plant a mono-crop, it would be easy for a disease or insect to destroy the entire crop (sometimes in the entire state.) If on the other hand, several rows of beans were used to separate several rows of corn, the insect or disease could be slowed down or stopped.

Terracing is another method used to control the runoff of water in areas with steep slopes. The land is leveled in order to prevent downhill runoff.

Windbreaks were first used in connection with the dust bowl. A windbreak causes the wind to swirl and it therefore does not cause as much damage. Wind blowing in the same direction for a long time is able to gain speed and therefore evaporate more water from the soil and move more topsoil.

No Till Farming has the advantage that the ground is never broken. the crops are mowed, herbicides are added and seeds with fertilizers are directly added to the soil.

Remote Sensing is the acquisition and analysis of information about objects or phenomena from a distance

Information from remotely sensed images allows farmers to treat only affected areas of a field. Problems within a field may be identified remotely before they can be visually identified. Ranchers use remote sensing to identify prime grazing areas, overgrazed areas or areas of weed infestations.

Soil as a Vector VECTOR means “carrier”

SOIL AS A VECTOR… Although I am not an expert on the subject of soil pathogens, what I have learned is that soil from wilderness areas and farming and vegan soil that has only had green manures and compost made only from plant material, appears to be much less likely to be a vector for pathogens.

Improve soil management Practice: * contour plowing * reduced tillage or no tillage, * using windbreaks to reduce wind speeds at the land surface, * allowing soils to rest * promote humus production

The importance of groundcover

Good soil stewardship, means food and resources for the future.