it's the millennium success series : Integrated Science for Junior High Schools Volume

BOOK18

SEED BED

INDICATORS and EXEMPLARS In reality, a seed bed may not comprise

of only a soil mass but a boundary
At the end of this sub strand, the frame such as an elevation.
student should be able to:
The seed bed is used mostly to grow
1. Explore the different seed beds for planting seeds in a controlled/regulated
crops in your community. environment before they are
2. Plant different types of crops on different transplanted; i.e. transported to the
seed beds. farm or garden.
3. Compare and contrast the differences in
height, size and flowering of crops grown in
different seed beds.

Seed bed preparation

The entire process of preparing a seed

bed is grouped into five [5] stages/steps.
SEED BED [SEEDLING BED]
These are;
The seeds [matured ovules] of plants are 1. The removal of stumps, stones and
used for two [2] general purposes. debris that can physically prevent the
seedling germination and growth.
The seeds of most plants are used/eaten
as food and others are used to grow 2. The leveling up of the site/area which
has demarcated for the bed for uniform
new/young plants.
[even] drainage; i.e. entr y and
distribution of water.
Every viable/good seed has certain
requirements that it needs before it can 3. Making the soil loose by digging and
germinate; i.e. grow into a young plant. breaking lumps.
And as a result, seeds are usually sown;
i.e. planted on seed beds. This practice promotes the entry of air;
i.e. improves aeration, and the entry of
water; i.e. improves drainage.
A seed bed [seedling bed] is a local soil
environment within which seeds are It also helps the root of seedlings to
nursed/planted. penetrate the soil.
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Note: Smaller seedlings generally 4. To ensure a shallow planting depth for

require a fine granular soil structure easier replacement of non-germinating
which can be obtained/designed with a seeds and an early germination of the
tool like the rake. viable seeds.

4. Improving; i.e. enhancing the soil Note: An improper sowing/planting

structure by adding organic matter depth can affect the chances of seed
[humus]. germination.

5. Adjusting the nitrate and the 5. To firm the soil and make it easier for
phosphate levels of the soil using the right small seeds to come into contact with
fertilizer. water.

Note: Any micro-nutrient which is found Note: Water plays an important role in
to be deficient/lacking in the soil can be seed germination by softening the
added at this time. cotyledon; i.e. stored food into a form
that can easily be changed/turned into
energy when oxygen acts on it.
This energy is used by the seed for the
Reasons/impor tance/benefits for growth process.
preparing a seed bed

1. A seedling bed is used to increase the 6. Seed bed preparation also presents
chances of the number of planted seeds an opportunity to mix organic matter
that can germinate per unit area of land. and other materials that can improve
soil fertility.
2. It reduces or eliminates competition
for the seedlings because weeds and
other unwanted plants can easily be
controlled or removed from the seed Types of seed beds [seedling bed]
bed.
There are three [3] types of seed beds
Note: Since it is easier to kill weeds before based on the nature of their surfaces.
seed planting, a good seed bed should These are; flat beds, raised beds and
be free of any visible weeds at the time of sunken beds.
planting.
Each seed bed has some unique
3. To conserve/save water for the planted features that suit a specific climate, soil
seeds or germinating seedlings through type, crop management and available
the easy elimination/removal of other equipment for cultivation.
competing vegetation like weeds.
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 it's the millennium success series : Integrated Science for Junior High Schools Volume
BOOK18

Flat beds Raised beds

Flat beds are used where water Crop plants can be grown/cultivated on
availability is adequate with no raised-up beds or ridges.
drainage problems.
Flat beds are usually enhanced during These beds are especially
the farming season. For instance; in advantageous/beneficial for clayey soil
some areas, crops like; maize, sorghum, at places with high rainfall or with soils
beans and potatoes can be that have poor drainage.
started/cultivated on a flat bed.
But as the season progresses, soil is This system is ideal/popular with the
thrown into the crop row to mound up; furrow irrigation system.
i.e. heap around the plant. This is called
hilling-up. Note: Furrow irrigation is the supply of
water to crop plants through furrows; i.e.
Hilling-up is done to; control in-row channels holes between crop
weeds, provide support for the growing beds/ridges.
plants and to improve the soil drainage.
The height of raised beds ranges from
Root tubers [tuber drops] like; potatoes 10cm to 30cm high depending on the
are also hilled up to keep their roots in the soil properties/characteristics.
soil.
This protects the tubers from rodent For example; clay soils at places which
attack and other infection. experiences high annual rainfall could
be made to about 20cm to 30cm in
Note: Hilling-up is good and works well for height because clayey soils have high
plants with that have enough stem height water drainage.
and broader leaves that can
tolerate/survive partial soil burial. On the contrary, a sandy soil at a place
with similar annual rainfall like the above
could have a bed height ranging from
15cm to 20cm.

Finally, at more drier conditions/places, it

is advisable for bed height to be lower
than 10cm in height for adequate
drainage.
These alternations/changes in the
height of raised beds with the various soil
types at places with different climatic
conditions is important against water
A flat bed with uniform surface loss.
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Note: Water is mostly lost from raised The lips/boundaries of a raised bed can
beds through the exposed sides. be raised to suit the rainfall pattern of the
place.

Advantages of raised beds over flat

beds other beds Sunken beds
In dry regions/places, with sandy soils that
1. Raised beds have better/improve have relatively low water holding
drainage compared to flat or sunken capacity, vegetable crops can be
beds. planted/raised in sunken beds; i.e.
2. They provide a double layer of topsoil shallow basins of about 100cm to 130cm
which makes the particles more loose wide and 2cm to 5cm of the surrounding
than flat or sunken beds. soil level.

Note: Raised beds are made by the Sunken beds are advantageous
heaping up of topsoil from the because they are able to
surrounding alleys. conserve/retain water for two [2] main
reasons;
3. Plants on raised beds are easier to
reach during manual activities; i.e. hand 1. Sunken beds usually do not have the
operations like weeding and thinning out. exposed sides unlike raised beds from
Even though raised beds have these where considerable moisture can be
advantages above, yet they are not a lost through evaporation.
good choice during the dry season.
2. None of the captured/supplied water
This is because they tend to dry out; i.e. can be lost as run-off.
lose water more quickly than flat or
sunken beds through; evaporation, the
alley-ways and as run-off.

These can be minimized by mulching,

making a lip around it or reducing the
height of the bed to about 10cm or less.

forms of raised bed

A major disadvantage of every sunken

bed is that some topsoil is lost during the
forms of raised bed preparation/construction process.
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 it's the millennium success series : Integrated Science for Junior High Schools Volume
BOOK18

Sunken beds are made by small rubber bag or a container.

pulling/digging off soil from the bed area
and placing it in the surrounding Several of such bags are brought/put
alleyways. together to form the nursery bed.

However, this probably won’t affect crop The nursery bed is usually put under a
growth, as long as the topsoil is of the shed/shade to prevent/check excess
normal height of about 15cm and evaporation.
enough compost/manure is added.

Here are two [2] ways of building a

sunken bed without sacrificing the
topsoil.
1. First, take off the topsoil and then
replace it after removing enough subsoil
to sink the bed.
2. Make a pseudo sunken bed by
mounding alleyway soil around the bed
borders. a farmer watering his seedlings in the
nursery
This works better in clayey soils than sandy
soils; which can be easily washed away
during irrigation or watering due to the
loose nature of the soil particles.
LIKELY EXAMINATION QUESTIONS
However, one variation benefit of sunken 1. All the following are benefits of
beds is furrow planting in which crops preparing a seed bed except?
like; maize, sorghum and beans could A. It helps root and tuber crops to
be planted in the furrow bottom/base develop well.
between two [2] ridges where soil B. It prevents the seeds from being lost to
moisture is higher and not easily lost. erosion and birds.
C. It increases the chances of
Soil can also be thrown into the furrow germination
during the season to control weeds and D. It makes the process of cultivation
improve drainage if rainfall increases. more difficult.

2. There are ........ types of seed beds

A. 2 B. 3 C. 4. D. 5
Nursery beds
In the nursery, seeds can sometimes be 3. The sunken seed bed is ideal for
nursed in a special soils collected into a cultivating crop plants
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Table
Cycles
Dedication
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to Integrated Science

A. at places with high rainfall

B. at places with low rainfall
C. on lands with hard and rocky soil
D. on lands with soft and loose soil

4. Which of the following tools in not used

during the preparation of seed beds?
A. Shovel B. Plough
C. Rake D. Sickle

5. During crop production, the

appropriate time for making seed beds is
A. Before planting of seeds
B. After planting of seeds
C. Before harvesting
D. During weed control.

6. What is a seed bed?

7. Describe briefly the major types of seed

beds in crop cultivation

8. Give two benefits of seed beds in the

nursery.

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