Looking for something else?
Have you ever looked at the soil in your garden and considered
it as anything more than soil? If not you should because there
is a lot more there than meets the eye. It performs many
functions that you may not be aware of and having good quality
soil in your garden is essential for your plants. In this
article we will look at the functions of soil, what different
types there are and finally some ways to make it healthier.
Functions of Soil
The most immediately apparent function of soil is a medium to
support plant life. It provides support both physically and
biologically. Physical support is provided by allowing the
plant to grow its roots through the soil to hold itself in
place. Biological support is provided by its ability to hold
nutrients and water that the plant needs. It also supports
other types of life as well. Microorganisms and insects live in
the soil and they in turn aid plant life by helping to decay
organic material and adding structure to the soil.
Soil allows
the growth of food crops which are consumed by humans and also
plants used in the creation of medicines. Microorganisms like
fungi and bacteria that live in soil and are used to produce
antibiotics. All life on earth is dependant on it either
directly and indirectly. This includes the plant life in your
garden.
What is Soil Made of?
The four major components of soil are mineral matter, organic
matter (humus), water and air. Mineral matter refers to the
inorganic elements in the soil e.g. stones, gravel and makes up
to 40%-60% of its volume. This part of the soil usually
originates from the bedrock that lies beneath the soil. Organic
matter (humus) is the decayed remains and waste products of
plants and animals and has a great effect on the chemical
properties of the soil e.g. availability of nutrients. Almost
40%-60% of a soil's volume can be space and this is occupied by
water and air.
Different Types of Soil Texture
Soil texture is defined as the size distribution of different
mineral particles. These mineral particles are at their most
basic level the following: sand, silt and clay. Sand particles
are 2 to 0.05 mm diameter, silt particles are 0.05 to 0.002 mm
diameter and clay particles are less than 0.002 mm diameter.
Combination of these particles exhibit different properties in
soil and some combinations favour plant life better than
others. The following are the most common classes of soil
texture:
Clay soil
Contains a high percentage of clay particles and feels lumpy to
the touch. The small size of the clay particles means that they
clump together quite readily and there is less room for air
spaces. Consequently clay soils have poor drainage and do not
hold nutrients very well. This is a heavy soil and is sticky
when wet making it hard to work with. As much as possible you
should take steps to improve the drainage of this type of soil.
You will learn how later on in this article.
Silty soil
Contains a high percentage of silt particles and feels smooth
to the touch. This soil is a well drained soil due to the size
of the particles allowing space for water to permeate. This
soil holds nutrients more readily than clay soil due to the
spaces. It is easy to cultivate but can be compacted quite
easily.
Sandy soil
Contains a high percentage of sand particles and feels gritty
to the touch, Allows for quite a lot of space in between
particles and as a result is very free draining. This has its
disadvantages however as it does not hold water and essential
nutrients can get washed away.
Loamy soil
This is the best type of soil texture you can have in your
garden. This is soil whose properties are controlled equally by
the percentages of clay, silt and sand particles. It is well
drained but does not loose water too easily as is the case with
sandy and sometimes silty soils. The fact that it retains water
means it also retains nutrients for your plants to use. It has
a great structure and is easy to cultivate.
What Makes a Soil Healthy?
Healthy soil must be fertile and have a good structure.
For a soil to be fertile it must have nutrients readily available and a pH value at a recommended level for the plants that will reside in it. Nutrients that should be available are the essential nutrients nitrogen (leaf growth), phosphorous (root growth) and potassium (overall health).
As well as the
essential nutrients there should also be trace elements like
calcium and magnesium. The pH level of the soil refers to its
acidity or alkalinity and each plant has its own preferred
value range. Plants placed into fertile soil will grow up to be
very strong and healthy specimens (that is if other conditions
like light levels and climate are favourable as well).
The other determiner of a healthy soil is its texture. We
learned about different types of soil texture earlier in this
article. Soil having a loamy texture is the healthiest and it
should be strived for if at all possible. In general a soil
that retain nutrients and allow water and air to permeate it
will be beneficial for the life of your plants.
How to Create Healthy Soil
No matter what type of soil you have, the addition of organic
matter will work wonders for its health. Organic matter is
plant and animal residues in varying forms of decomposition. It
will replenish the nutrients in your soil and improve its
texture.
You may have heard countless times about adding your
leftovers and glass clippings to a compost heap. This is a
great idea as your compost is the best form of organic matter.
Compost in an advanced stage of decomposition (dark and without
smell) is magic for your soil. It encourages microorganism
activity causing soil particles to clump together and form
aggregates. The aggregates allows for spaces in the soil
therefore increasing its drainage. This is especially
beneficial for clay soils, which have poor drainage. Other
forms of organic matter are animal manure and peat moss.
If your soil is lacking in nutrients and you don't have access
to a compost heap you have a choice of using inorganic or
organic fertilizers. Inorganic fertilizers (inorganic salts,
manufactured chemically) can be purchased at your local garden
and are applied in a dry form that is raked lightly at the base
of a plant or in a liquid form. While inorganic fertilizers will
work fine they have a number of disadvantages: they release
their nutrients too quickly and there is some evidence to show
that plants develop a resistance to inorganic fertilizer
methods over time, requiring more and more to achieve the same
effect.
Organic fertilizers are more in tune with nature
because they are created from the remains or by-product of an
organism. They act slower but they 'amend' the soil rather than
'quick feeding' it like inorganic fertilizers.
The pH of your soil will also affect its fertility. Each plant
has its own preferred pH value range. To learn more pH and how
to change it read my Soil pH article here:
www.gardenstew.com/blog/e3-9-soil-ph-and-its-effect-on-your-garden.html
Conclusion
Soil like a lot of things in the garden requires maintenance.
We have learned about the different types of soil texture, what
constitutes a fertile, healthy soil and how to create it if it
does not exist. The next step is to step out into your garden,
take a look at your soil and help your plants out if your soil
is of a poor quality. Your plants will thank you ten-fold,
believe me.
Good luck!
©2005 Francis Kilkelly. All rights reserved.
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