The soil is not dirt, dirt you wash off. The soil is a rich amalgamation of decomposition. From chemical decomposition of rocks into sands, silts and clay, to organic decomposition of plant and animal material and most importantly, the little bugs and bacteria that feed on the decaying material and transform the raw nutrients into plant friendly forms.
Inorganic (Sand, Silt, Clay)
Is your soil sandy, silty or clay? The ratio of sand to silt to clay which makes up your soil classification. To determine this base classification of your soil is as simple as putting some soil in a jar with some water and shaking it up.
Jar test for soil
- Take a Jar – any jar with a cover, and shape, size, as longs as its clear glass or plastic.
- Put masking tape vertically down the side.
- Mark off 10 cm (or ten inches – ten is key)
- Fill jar to the 10 cm line with your soil
- 3/4 fill the entire jar with water over the soil
- Shake well
- Let gravity work
First to settle to the bottom will be the sand, usually within a minute
Silt particles settle within the hour
Clay may take days or weeks to settle out (measured after 24 hours)
Stuff floating is organic – and you can just disregard that.
How many cms of sand: 3 cm
How many cms of silt: 4 cm
How many cms of clay: 2 cm
Soil composition: cm’s of material/total cm of all material * 100% = %material
Sand: 3/9*100% = 33% Sand
Silt: 4/9*100% = 44% Silt
Clay: 2/9*100% = 22% Clay
But that doesn’t add up to 10cm. Well no, the remainder is your organic component.
10% organic (this is just an approximation and for general knowledge)
These three numbers, used in the standard soil classification chart determine your soil classification. Start on the left side, and horizontal lines indicate %clay from 0 to 100 at the peak of the triangle. Then either %sand (left leaning diagonal lines) or %Silt (right leaning diagonal lines)will determine the classification. In the case above it puts it right in the loam category – a good mix.
Sandy soil will not hold water or nutrients well
Clay soils will hold too much and could suffocate the roots of your plants. Care must be given to clay soils when working as it can easily turn hard like concrete when it dries.
The soil classification is a great thing but what does it mean?
The soil classification is necessary, not for what’s there, but rather what isn’t. The spaces between the soil particles are what is most important. That is where the bugs and microbes live. That is where the nutrients and water for the plants is.
Two additional vital ingredients to soil, water and air. The soil is an ecosystem of living things that break down organic things into nutrients for the plants to eat. All living things need oxygen, water and food to survive. The food comes from the natural materials (decomposition), the air and water are a result of the soil classification.
A healthy and productive soil will have a productive ecosystem for a broad range of micro-organisms, bugs and worms. The more things that thrive in your soil, the better as their common goal is to break down the components of your soil into beneficial nutrients to help your plants grow.
What to do with this information?
This information will give you an idea on how to fix soil conditions, or modify your practices to best utilize the soils you have. For example in a sandy soil, a little more watering, maybe some mulch to hold in moisture. In clay soils work it as little as possible when wet, maybe less watering. Just Google your soil type and “remedies” and you will be rewarded with a plethora of ideas based on your soil type.