Soil Much more than "dirt"

Why is soil important? Soil is the growing medium for our food Without it we could not survive Soil purifies our waste Soil is home to plants and animals It may take 100’s of years to form one inch of topsoil We are losing so much soil to erosion each year that the lost soil if loaded into dump trucks parked back to back would extend to the moon and back.

Animals making burrows in the soil help bring air and water into the soil

Soil Structure

Soil Structure affects: -how easily soil can be cultivated -how vulnerable it is to erosion -soil permeability

Soil Horizons O (Organic Horizon made of dead leaves and other detritus) A (made of organic matter mixed with mineral soil) E (Sometimes present….the zone of elluviation… clay and other mineral particles move out of this horizon and into lower horizons…light colored…zone of maximum leaching B (Zone of illuviation…..clay and minerals leach into this horizon from upper horizons) C (contains weathered parent material)

http://www.enchantedlearning.com/geology/soil/soillayers.GIF

http://upload. wikimedia. org/wikipedia/en/thumb/9/92/Podzol http://upload.wikimedia.org/wikipedia/en/thumb/9/92/Podzol.jpg/180px-Podzol.jpg

http://wps. prenhall. com/wps/media/objects/1411/1445480/spodosol_NRCS http://wps.prenhall.com/wps/media/objects/1411/1445480/spodosol_NRCS.jpg

Soil Samples from Around the World http://www. anra. gov

What makes up soil? Soil is made up of mineral grains. Water is held between the grains in the pore spaces. 25% of the soil is air. Oxygen is essential Organic matter is both coarse and fine. Bacteria- A thimble of soil can contain 2 billion bacteria, 30 million fungi fragments and 100,000 single cell plants and animals. What makes up soil?

Soil Texture http://cst. cmich

Soil texture refers to grain size Sandy particles are the only particles which may be large enough to be seen with the naked eye. Predominantly sandy soil has a gritty feel (coarse-textured) when rubbed between the fingers. Silt particles are smaller than sand particles. Predominantly silty soils feel powdery (like flour) and do not hold together well when wet, though they are more cohesive than sandy soils. Clayey soil has the smallest soil particles, and many small pore spaces. Soils with a high number of clay particles have a very high water holding capacity and are very fine-textured, making them feel smooth and sticky (like soap) when wet. Loam is the best soil texture for growing things. It is a mixture that has useful amounts of clay and silt in a base of sand.

Separating Sand, Silt and Clay http://www. ext. colostate

Soil texture graph

Effects of Soil Texture on Drainage http://www. fao

Separating Sand, Silt and Clay http://www. ext. colostate

Coarse-textured soils have a high sand content Coarse-textured soils have a high sand content. They consist of large particles with uneven surfaces and because of this, have large pore spaces These traits make such soils loose and easy to work; however, the large spaces do not retain water or nutrients. Water infiltrates sandy soil and percolates (moves through it) quickly and easily. As a result, sandy soils are generally dry and infertile.

Medium-textured soils known as loams, have properties in between those of coarse and fine texture. Silty loams to sandy-clay loams have a good capacity to retain water without becoming waterlogged. They are easy to work and form good clumping mixtures during cultivation. Loams contain a good supply of nutrients, necessary for the organisms living in the soil. Loam or silty soils have a texture which is most suitable for the greatest variety of living organisms.

Fine-textured soils range from silty clay to heavy clay. Heavy clays are like soft plastic when wet and are hard when dry. This makes them difficult to work. Clays are often waterlogged and poorly aerated, as well as being cool. Clay soils absorb and release water (to plants) very slowly. Air movement within the soil is also very slow. These conditions mean that clay soils take longer to warm than coarser soils. A lot of water in the spaces can mean little air is available for living organisms to carry out cellular respiration and certainbiochemical actions.

Fertile soil contains nutrients Fertile soil contains nutrients. There are major nutrients and micro nutrients. Major nutrients make up the bulk of the nutrients in your soil. The most important major nutrients are :Nitrogen, Potassium and Phosphorus. Other major nutrients are :Calcium, Magnesium and Sulfur. Micronutrients are: Manganese, Iron, Copper, Zinc, and Boron. Nutrients need to be balanced and available to the plant's roots. Organic matter is key to helping maintain this balance.   Fertile soil contains nutrients

Ion exchange in soil

Addition of lime helps to neutralize acidic soil Addition of lime helps to neutralize acidic soil. The calcium and magnesium ions in lime will bump some of the hydrogen ions off the clay particles. The hydrogen is then leached downward by water and the soil becomes less acidic.

Acid Loving Plants

                       Soil Testing Kits