- Planting materials are either planted directly in a seedbed or indirectly through a nursery bed.
- A seedbed is a piece of land which could be small or large and prepared to receive planting materials.
- A nursery bed on the other hand is a small plot of land specially prepared for raising seedlings or planting materials before transplanting.
- It is usually 1m wide and any convenient length depending on the quantity of seedlings to be raised.
- A seedling bed is a special type of nursery bed used for raising seedlings pricked out from the nursery bed due to overcrowding before they are ready for transplanting.
- Pricking out refers to the removal of seedlings from a nursery bed to a seedling bed.
- Nursery practices refer to all the activities carried out throughout a nursery life to raise seedlings. .
Importance of Nursery Bed in Crop Production
- To facilitate the production of many seedlings in a small area.
- It is easy to carry out management practices in a nursery than in the seedbed.
- It facilitates the planting of small seeds which develop into strong seedlings that are easily transplanted.
- It ensures transplanting of only healthy and vigorous growing seedlings.
- It reduces the period taken by the crop in the field.
- Excess seedlings from the nursery may be sold to earn income.
Selection of a Nursery Site
Factors to consider;
- Nearness to the water source.
- Type of soil.-should be well drained, deep and fertile, preferably loam soil.
- Topography.-it should be situated on a gentle slope to prevent flooding and erosion through surface run-off.
- Previous cropping.-to avoid build up of pests and diseases associated with particular plant families, consider the preceding crops.
- Security.-select a site that is protected from theft and destruction by animals.
- Protection against strong winds and heat of the sun.-select a sheltered place. i.e. to avoid excessive evapotranspiration and uprooting seedlings.
Types of Nurseries
Categories of nurseries:
- They are used for raising the seedlings of vegetable crops.
Tomatoes, cabbages, kale, onions, brinjals and peppers.
Vegetable Propagation Nurseries:
- They are used for inducing root production in cuttings before they are transplanted,
- The cuttings can be planted directly in the soil and hence called bare root nurseries.
- Or planted into containers such as pots, polythene bags and others, hence called containerized nurseries.
- These are used for raising tree seedlings.
- The seedlings can be raised in bare root nurseries or in containerized nurseries.
Nursery Management Practices:
- These are the practices carried out in the nursery while the planting materials are growing.
- Mulching. –light mulch should be applied on thenursery bed.It be should be removed on the 4th day
- Weed control.
- Pricking out.
- Pests and disease control.
- Hardening off
Preparation of vegetative materials for planting:
- Cuttings -These are plant parts such as stems, leaves and roots induced to produce roots and used as planting materials.
- Grafting –
- It is the practice of uniting two separate woody stems.
- The part bearing the roots is referred to as root stock while the part which is grafted onto the rootstock is known as
- The scion has buds which develop into the future plant.
- The ability of the rootstock and the scion to form a successful union is termed as
Methods of Grafting
Whip or tongue grafting:
- In this case the diameter of the rootstock and the scion are the same.
- It is carried out when the diameter of the scion and the rootstock is ‘pencil’ thick.
Side grafting: In this case the diameter of the rootstock is bigger than that of the scion.
Other types of grafting include ;
- Approach grafting,
- Notch grafting
- Bark grafting.
- It is the practice of uniting a vegetative bud to a seedling of another plant.
- The scion has only one bud and some bark with or without wood.
- The bud is inserted in a slit made on the bark of the stock.
- It is held tightly on the stock by tying with a budding tape until it produces a shoot.
Methods of Budding:
- Top budding
- Patch budding.
Importance of Budding and Grafting:
- Plants with desirable root characteristics but with undesirable products may be used to produce desirable products for example lemon-orange graft.
- They facilitate the changing of the top of the tree from being undesirable to desirable
- They make it possible to grow more than one type of fruit or flower on the same plant.
- They help to propagate clones that cannot be propagated in any other way.
- They help to shorten the maturity period.
- It is the process by which a part of a plant is induced to produce roots while still attached to the mother plant.
- Once the roots have been produced, the stem is then cut off and planted.
Types of layering;
- Marcotting or aerial layering.
- Tip layering.
- Trench layering.
- Compound or serpentine.
Tissue Culture for Crop Propagation
- Tissue culture is a biotechnology used in cloning vegetatively propagated plants.
- It is based on the ability of plant tissue (or cells) to regenerate other parts of the plant.
- The tissues are derived from shoot tips where cells are undergoing rapid cell division and are not differentiated.
- The cells are then provided with the right conditions which enable them to multiply and develop roots.
The Right Conditions for tissue culture:
- Culture medium.
- Correct temperature.
- Correct light intensity and
- Correct relative humidity.
Importance of Tissue Culture in Crop Propagation
- It is used to recover and establish pathogen-free plants especially in the control of viral diseases.
- It is used in mass production of plantlets or propagules.
- It is fast and requires less space than the cultural methods of using cutting which requires a bigger space.
- Transplanting of vegetable and tree seedlings are generally the same.
- Generally, vegetable seedlings are ready for transplanting when they are one month old or have 4 -6 leaves or are about 10-15cm in height.
- Before transplanting, the nursery bed is adequately watered 3 – 4 hours before lifting the seedlings.
- This ensures the seedlings are lifted easily with a ball of earth around the roots to minimize root damage.
- Tree seedlings take a little longer to reach transplanting age compared to vegetable crop seedlings.
- The roots are trimmed before lifting the seedlings.
- Transplanting should be done at the onset of the long rains to give the young trees a good start.
- After transplanting the young trees should be protected from damage by animals for a period of about one year.
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