Natural Sciences and Technology Grade 5 Term 4: Planet Earth and Beyond Surface of the Earth (PPT 3)

Topic 2 Surface of the Earth Soil types Gr 5 Natural Sciences and Technology – Term 4, Topic 2

What is soil made of? Rocks break down and change into sand. This is a very slow process. Sand is not soil. Soil is: mixture of different soil grains. decomposing plant and animal parts. minerals from rocks. nutrients from plant and animal parts. Gr 5 Natural Sciences and Technology – Term 4, Topic 2

Different types of soil Three different types of soil (sandy, clayey, loamy) Contain different proportions of soil grains All three types contain: Soil grains Air Water Animal and plant matter Small organisms There are three different types of soil. The soil contain different proportions of soil grains. Proportion is the relationship between different parts regrading size and amount. All three types of soil contain soil grains, air, water, animal and plant matter and small organisms. NATURAL SCIENCES GRADE 5

NATURAL SCIENCES GRADE 5 Type 1: Sandy soil Lots of big sand particles (rocks that break up) Rough /course texture Large air pockets between the sand particles Can hold a lot of air and a little bit of water Does not retain fertilisers Easily blown and washed away Sandy soil has a big amount of course sand grains. This means that there are lots of big sand particles. This type of soil has rough texture. You can easily feel the separate particles when you rub sandy soil between your fingers. The spaces between the sand particles are large compared to other soil types. This means that sandy soil can hold lots of air and water. NATURAL SCIENCES GRADE 5

NATURAL SCIENCES GRADE 5 Type 2: Clayey soil Lots of fine grains of clay Can be moulded Smooth texture when dry; sticky when wet Spaces between the clay particles much smaller, with smaller air pockets Very little air Lots of water Retains fertilisers for a long period Clay soil has a high proportion of fine grains of clay. Because of the size of the particles, clay has a smooth texture. When you rub clay between your fingers, you cannot feel the separate particles. The spaces between the particles are much smaller than sand. There is very little air in clayey soil, but it can hold lots of water. The particles stick together even when the soil is dry. NATURAL SCIENCES GRADE 5

NATURAL SCIENCES GRADE 5 Type 3: Loamy soil Mixture of clay, sand and humus (decomposed animal/plant matter) Smooth and powdery texture Fertile and loose (best soil for plants to grow in) Spaces are smaller than those of sandy soil Contains small rock particles Contains less air than sandy soil Absorbs more water than sandy soil Loamy soil is a mixture of clay, sand and other soil grains. The soil has a slightly coarse texture, but not as coarse as sand. The spaces between loam soil particles are smaller than the spaces of sandy soil. Because of this, loamy soil contains less air than sandy soil, but it can absorb more water. It is a bit like a sponge, because it can soak up / absorb so much water. NATURAL SCIENCES GRADE 5