Studying Soil Scientifically

Things plants need in order to grow: 1) Sunlight 2) Water 3) Air 4) Soil with proper nutrients.

Characteristics of Soil Color Texture Consistence

Soil Color Includes colors such as: Chocolate Brown Yellowish Brown Grayish Brown Reddish Brown

Soil Texture 1)Grainy – has large pieces that feels gritty like sand 2)Silky – has medium sized particles that feel powdery 3) Sticky – has small pieces that feels gummy like clay.

Soil Consistence 1)Loose – soil that falls apart easily 2)Friable – soil that can be broken apart with fingers 3)Firm – soil that is not crushable between thumb and finger

Soil is made up of many things. Some of which include: 1)Weathered rocks 2)Organic Matter 3)Air 4)Water

Weathered rocks in soil come in different sizes. Scientists have names for the different sized particles: 1) Clay – the smallest particles which can not be seen without a microscope. They are less that mm. 2) Silt – medium sized particles that range between mm. 3) Sand – Largest particles that range from 0.05 – 2 mm. 4) Rocks – particles over 2 mm in size.

Organic Matter When plants and animals die and decompose, the nutrients found in the once-living organism are broken down into chemicals that are returned to the soil for other plants to absorb and use as nutrients that help them grow.

Soil is found in layers: 1)Topsoil – is the uppermost layer. It is a combination of rock, sand, silt, clay, organic matter, air, and water. It’s average depth is 20 cm. Plants grow roots in this layer. 2) Subsoil – Not much organic matter found in this layer. Some nutrients get washed down into this layer as water drips through the soil. Plant roots grow into this layer.

Soil Layers (continued) 3) Parent Material – Made up of slightly broken up bedrock. Roots usually don’t grow down into this layer. Very little organic matter found here. 4) Bedrock – hard, solid, rock that lies beneath all of the other soil layers.

Types of Soil: 1)Desert Soil 2)Grassland Soil 3)Forest Soil 4) Tropical Grassland Soil

Desert Soil -It forms in places that do not get much rain and has high temperatures year round. -The soil is dry and sandy. -This soil is easily moved by wind and water. - Soil is light in color, has a firm consistence, and a gritty texture.

Grassland Soil -It forms in areas that have both wet and dry seasons, but less overall rain that the areas that have forest soil. -The topsoil contains a lot of nutrients. -It is good for farming. - The soil is a reddish brown color, has a loose consistence, and a silky texture.

Forest Soil: -It forms in areas that have hot and cold seasons and receive enough rain year round to support a lot of tree growth. -It is often good for farming. - It has a grayish brown to reddish brown color due to small amounts of iron or aluminum. - It has a loose consistence, and a sticky texture.

Tropical Grassland Soil: -It forms in areas that are very warm all year round and have both wet and dry seasons. - It is a grayish brown color and the texture is sticky.

Farming Techniques that would help prevent another “Dust Bowl”: 1)Contour plowing – is used on hills to slow down water flow so that less soil is washed away. 2)Windbreaks - lining fields with trees to slow the wind so it can not easily lift and move soil. 3) Crop rotation – changing crops yearly to reduce the loss of nutrients in the soil.

Fertilizers can be used to replace chemical nutrients that are missing from soil. Some of the most important nutrients needed to help plants grow are: 1)Phosphorus 2)Nitrogen 3) Potassium

Manufactured Fertilizer Contains larger amounts of nitrogen, phosphorus, potassium, and other nutrients. The nutrients are released into the soil quickly. More expensive. Nutrients wash away more easily and can pollute the rest of the environment.

Organic Fertilizer Contain natural material, such as manure, compost, or peat that will slowly decompose and release nutrients into the soil over time. Less up-keep The nutrient content is lower. Nutrients are less likely to wash away. Takes longer to get started.