Soil Properties That Affect Growth of PlantsWhat is Soil made of?Soil is made up of a mixture of many things. All soils have these 4 basic ingredients:

Humus, which is made up of once-living substances. Sediments, such as rocks, sand, silt, or clay. Air Water.

Soil Property 1: ColorThe most obvious property, when looking at soil, is its color. The color of soil can tell scientists a lot about it. Geologists officially recognize over 170 different soil colors. Most of these are shades of black, brown, red, gray, and white. Generally speaking, the darker a soil, the more nutrient rich it is. The darker color often means that there is a higher content of decomposed organic matter known as humus.

Gray soils often indicate poor drainage, while red soils can indicate very poor soils. These general rules about soil colors can, however, be misleading. Under certain conditions, a very poor soil can appear as dark black, while a rich healthy soil can appear as red.

Soil Property 2: TextureAnother easily experienced property of soil is texture. Pick up a pinch of soil between your fingers and rub it back and forth. You will quickly notice that the soil is made up of many different sized particles. These particles give the soil its texture.

Geologists have named the larger particles of sediment sand. When sand weathers into smaller pieces, they turn into silt. When silt is broken down into even smaller particles, they become clay.

Some soils have more sand and less silt or clay, while other soils have an abundance of the smaller silt and clay particles with less sand. Some plants require a more sandy soil, while some plants require a more clay-based soil.

Soil Property 3: Capacity to Retain WaterAn important feature of soil is its ability to absorb and store precipitation when it falls onto the land. Scientists call this a soil’s capacity to retain water. When soil retains

water, a reserve of water is available for living organisms between events of precipitation.

How quickly water moves through the soil depends mainly on its texture. Sandy soils have larger pores (space between particles), so water flows through quickly. Silt and clay soils have smaller spaces between the particles, so water flows through more slowly.

Soils that retain water better are usually finer in texture. Also, soil that has more humus tend to retain more water.

Now that you have learned about 3 different properties of soil, use that information to answer these questions. Use the sentences stems provided to help you word your answers in complete sentences.

Questions for Reading:

1. What are the three properties of soil?The three properties of soil are……

2. What does the word “retain’ mean?“Retain” means….

3. Put the following words in order from largest to smallest particle size: silt, clay, sand, gravel.Put in order from largest to smallest particles size are these types of soil

Large:Medium:Small:Very small:

4. What is humus?Humus is……

5. What does the color of soil tell us?The color of soil tells us….