- Soil horizons
- How to get rid of a sod and make the soil loose - Also get rid of rocks and tree roots etc.
- Soil management for working with grelinette (2 x, one for deep, one for surface)
- Find instructions for digging with spade
- Water control, irrigation management, too high ground water ....
Why do we have to prepare a soil for a garden?
We wish to give advantage to the crops that we cultivate and not to many other plants that would otherwise grow in our garden. These other plants we usually call 'weeds.' When you start out with a garden that wasn't cultivated before, you generally first must get rid of the sod of grass and other plants that have formed. Another important matter is that you want to bring air into the soil. Aerating a soil is done by delving, digging or cultivating a soil.
Why does a soil need air.
- The roots of many plants cannot penetrate compacted soils.
- The roots of plants need oxygen. While the green parts of plants that live above ground do photosynthesize, meaning they form oxygen, the roots cannot do this. However, they are growing and need energy for this. To get this energy they use the sugars produced in the leaves. For this process of respiration, oxygen is needed and carbon dioxide released. When a soil becomes water-logged, the deeper roots of plants quickly die.
- Many micro-organisms (bacteria, fungi etc.) and small animals such as earthworms need oxygen. Not all micro-organisms need oxygen, but those that do without oxygen live in deeper soil layers. All these organisms are needed to decompose organic material such as leaves and animal waste. Plants get many nutrients from this decomposed material.
Also, when a soil isn't loosened, rain water can assemble in soil layers where the roots of your crops need to grow. In a loosened soil excess water can drain down to ground water level, and through the capillary flow [1] again reaches higher layers in times of dry weather.
We shall now first look at the different layers in a soil, then learn how to dig or cultivate a soil, and finally share some thoughts about water management in a soil.
Soil horizons
Soil horizons are horizontal layers in the soils whose characteristics differ from the layers above and beneath[2].
The diagram right shows the main soil horizons.
O horizon
This is a layer of Organic matter or plant residues, such as from leaves and branches, and also animal waste, in relatively undecomposed form. This is not the same as actual leaf litter, as the O horizon already contains weathered mineral particles that are part of the soil.
A horizon
The A horizon and O horizon together form what is known as topsoil. Topsoil is the upper, outermost layer of soil, usually the top 2 inches (5.1 cm) to 8 inches (20 cm). It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs[3].
Plants generally concentrate their roots in and obtain most of their nutrients from this layer.
In the O horizon we find dark decomposed organic materials, also called "humus"[4].
Soil organisms such as earthworms, potworms, fungi, and many species of bacteria live here, often in close association with plant roots. Therefore the A horizon is sometimes called 'biomantle.[5]'
