FROM BEDROCK TO SOIL Section 10 3 pg

FROM BEDROCK TO SOIL Section 10 -3 pg. 288 -293

WHAT IS SOIL?

ANSWER Soil� is a loose mixture of small mineral fragments organic material water Air that can support the growth of vegetation

VOCAB: Parent Rock � Rock formation that is the source of mineral fragments Bedrock � Layer of rock beneath the soil � So bedrock is the parent rock � The soil above it is call residual soil

Transported soil � Soil that is blown or washed away from its parent rock � Can be done by wind, water, glaciers moving, weather

SOIL TEXTURE Is the soil quality that is based on the proportions of soil particles � Can be small to big (2 mm) This affects the soil’s consistency � This is the soil’s ability to be worked/farmed

Large proportions-clay is difficult to farm in Soil texture influences the infiltration � (ability of water to move through soil) � Water needs to get to plants � But don’t want soil to be saturated in water

SOIL STRUCTURE Water and air movement through soil is influenced by soil structure This is the arrangement of soil particles � How spread out they are Clumpy-won’t let air or H 2 O through

SOIL FERTILITY Is the soil’s ability to hold nutrients and to supply nutrients to a plant Nutrients can come from parent rock Nutrients can come from Humus � Organic material formed in soil from the decayed remains of plants and animals � Broken down by decomposers

SOIL HORIZONS Soil ends up in a series of layers = Horizons Top layer- is humus—rich layer � Called top soil � Good top soil is necessary for farming Sediment middle Parent rock—bed rock bottom

SOIL PH Soil can be acidic or basic Scale 0 -14, 7 neutral below 7 = acidic � above 7 = basic � This influences how nutrients dissolve in the soil

Basic� nutrients Acidic� don’t dissolve-hurts plants can’t take in other certain nutrients Right p. H decides what plant can grow there

TROPICAL RAIN FOREST Air is humid, large amounts of rain, warm temp. Crops grown yr round Decay is at a high rate- so nutrients in soil

Soil � Nutrients low- heavy rain takes it to deeper part � Top soil is thin � Plants grow—take a huge toll on nutrients

DESERT Not a lot of rain, Very low rates of chemical weathering � soil is created slower Less able to support plants

Groundwater- comes from surround areas-comes to surface-then evaporates � can’t get all nutrients in time High is salts� toxic to plant

TEMPERATE FOREST/GRASSLANDS Much of USA is this Lots of weathering Get enough rain— � chemical weathering to happen Change in temp � -get frost action

Get thick fertile soil Most productive soil Midwestern = Breadbasket

ARCTIC Little rain— � chemical Soil forms slowly � Thin weathering is low and slow and don’t support life Low temp. — � low decomposition rate � Low number of nutrients

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