Soil

What we will cover

Theory What is soil ? Understanding your soil Soil Food web

Practical - Observations Soil sampling and analysis

What is Soil

A mixture of mineral matter, organic matter, water, and air

A thriving ecosystem

Very variable from place to place and forever undergoing change. The soil is dynamic.

Under appreciated.

Mineral Inputs-Rocks

Rocks break down overtime and by doing so contribute the mineral content to the soil .

Physical weathering- Frost shatteringRoot growth

Mineral Inputs-Rocks

Chemical weatheringNot only causes rocks to disintegrate, also changes the chemical nature of the minerals Water reactionsRoot Secretions Soil Organisms

Organic Inputs

Primary Colonisers

Transformation – Minerals

The disintegrated rock takes the form of three main observable particle sizes

SAND – SILT – CLAY

Transformation –Organic Matter In healthy soil organic material inputs decompose and transform into Humus

and minerals.

Humus

Persists in the soil providing foods and protective substances for plants

Holds incredible volume of water

Creates good soil structure

Creates ideal environment for soil life

Texture

Texture refers to the proportion of sand-silt and clay in the soil and can give us a read on how our soil will interact with vegetation and soil life.

Sand: Fast Drainage – easy to work – Low fertility – warms quickly

Silt: Med fertility – easy to work – prone to crusting – poor structure – drains well

Clay: High Fertility- hard to work- poor drainage- prone to compaction

Loam: Equal proportions of sand-silt and clay. The ideal texture

Structure

Structure refers to how the sand silt clay and SOM are bonded together into aggregates. A diversity of aggregates provides a diversity of pore space which is the ideal situation for plant growth and provides habitat for soil organisms

Organic Matter - Soil Food Web

Organic Matter - Soil Life

Organic Matter – Benefits of Healthy Soil Food Web

Increased Nutrient retention Improved crop quality Pest and disease suppression Improved soil structure Decomposition of Toxic chemicals A cleaner environment

Soil Profile

Most of the fertility is present in the top 10cms (The Rhizosphere) Most of the soil life inhabits this horizon Most of the crop plants we grow feed from this horizon

Indicator Plants

Cytisus scoparius - Broom : Infertile soil ,nitrogen deficient Achillea millefolium – Dry soil Rumex acetosella - Sorrel : Poor light dry, acid soil Stellaria media - Chickweed : Fertile soil Urtica dioecia - Stinging nettle : Fertile soil Sonchus sp – Sow thistle : Acid soil Caltha pulustris - Marsh Marigold : Poorly drained ,waterlogged soils Chenopodium album - Lambs Quarter : Previously cultivated soil

Other Soil Factors

pH Nutrient Storage Water Relations

Essential points

A diversity of soil life creates healthy soil

We are aiming to grow soil and the soil will take care of the plants

Organic matter is the most important ingredient for the

functioning of healthy soil therefore healthy plants

By adding organic matter we feed the soil and keep it in good

condition to take care of the plants

Only when fresh organic matter has been mineralised by the soil life is it available to plants.