Soil Types Classification and Testing Soil Classification Understanding

Soil Types Classification and Testing

Soil Classification � Understanding what type of soil is present is important because it determines what type of plant will be most suited to an area. � This can accurately predict yields of crops for agriculture. � This can also allow for different crops to be planted that will make the most money for farmers.

Systems to Soil Classification � There are two major systems: � 1) Vernacular system � 2) Scientific system

Vernacular System � Vernacular system was developed by land users. � For example, in vernacular system soil can be categorized as red soil, black soil, yellow soil, etc. � These classifications determine what the soil can be used for. � Very general, not scientific. � Mostly based on colour and what is growing well in the soil at the time it is tested.

Scientific System � In the scientific system, the soil can be categorized according to: ◦ the development of soil (how was it created? ) ◦ the amount of substances present in the soil (what is the ratio of organic matter, water, air and minerals? )

Particle Classification � As there are various systems to classify soils, it means soil classification is not static or has 1 way of going about it. � However, most classification of soil is based on the size of the particles it contains. � This classification helps to understand the basic properties of the soil and helps to conclude if the type of soil is good enough for gardening or farming

Types of Soil � Therefore depending on the size of the particles in the soil, it can be classified into these following main types: ◦ Sandy soil ◦ Silty soil ◦ Clay soil

Sandy Soil � This soil type has the biggest particles. � This creates better aeration and drainage of the soil. � This soil is granular and consists of rock and mineral particles that are very small, creating a gritty texture. � Sandy soil is formed when rocks such as limestone, granite, quartz and shale are weathered. � Sandy soil is easier to grow on if it is rich in organic material, but can also allow for too much drainage. � This can create over-drainage and dehydration of the plants in summer.

Testing for sandy soil: � To check if soil is sandy, moisten a small sample of soil and try to make a ball using your palms. � If the soil is sandy, then no dirt balls will form and the soil will crumble and fall through the fingers.

Silty Soil � Silty soil is considered to be one of the most fertile of soils. � It can occur in nature as soil, or is often found at the bottom of lakes or rivers. � It is composed of minerals like quartz and fine organic particles. � More nutrients than sandy soil and offers better drainage. � If it is fully dry it can look like dark sand.

Testing for Silty Soil: � To check if the soil you have is silty, take a small amount of moist soil and rub it between your fingers. � If the soil is silty soil, it will feel slick and stick to your fingers.

Clay Soil � Clay is a kind of material that occurs naturally and consists of very fine grain material with less air spaces. � It is difficult to work with this soil, because the drainage in this soil is low. � Soil can become water logged and damage roots. � Very heavy when wet and lots of fertilizers need to be added. � Clay soil is formed after years of rock weathering. � Rich in mineral content.

Testing for Clay soil � To identify if the soil is clay soil, take a soil sample and damp it with water. � Rub it between your palms. � You will find clay soil is sticky and retains a good amount of water.

Types of Soil � Sandy, silty and clay soil are the 3 main types. � There are subtypes, which are not as easy to test for. � These subtypes are: ◦ Loamy soil ◦ Peaty soil ◦ Chalky soil

Loamy Soil � This soil consists of sand, silt and clay to some extent. � It is considered to be the perfect soil for gardening. � The texture is gritty and retains water very easily, yet the drainage is good. � There are various kinds of loamy soil ranging from fertile to very muddy and thick sod. � Ideal for cultivation. � Good for vegetable patches or gardens

Peaty Soil � This kind of soil is basically formed by the accumulation of dead and decayed organic matter, it naturally contains much more organic matter than most of the soils. � It is generally found in marshy areas. � Decomposition is very slow because peat is naturally acidic. This can preserve materials. � This kind of soil is formed in wet climate. � Though the soil is rich in organic matter, nutrients present are fewer in this soil type than any other type because of the slow decomposition. � Usually added to basic soil to increase water retention.

Chalky Soil Basic (alkaline) in nature, opposite to peaty soil. � Can have a large number of stones. � A lot of watering and fertilizer needed to grow plants well. � Also blocks the nutritional elements for the plants like iron and magnesium. �

p. H of soils � In this classification, soil is either acidic or alkaline soil depending on the amount of humus (completely broken down organic matter), organic matter and the underlying bedrock/parent material.

p. H Scale � All materials have a p. H level. � This determines how acidic or basic (alkaline) a material is. � If something is acidic, it will have more hydrogen (H) in it. � If something is basic, it will have more hydroxide (OH) in it.

� Most plants prefer a p. H level of 5. 8 -6. 2. � In Manitoba, our water is closer to 7. � Therefore, sometimes acids have to be added to soil to decrease the p. H to a more acidic level. � This can be done through fertilizers and solutions. � This also depends on the specific plant and the p. H of the soil itself.