Monday, July 15, 2024
General Agriculture

Principles and Operations in Tree Crop Production

The trees found in permanent crop plantations develop from small seeds. The selection and care given to the small seeds at the early stages of the crop plant determine the physical wellbeing of the crop plantations in later life.

In this article, you will study about the selection, care, growth and maintenance of the permanent crop plants.

Common features at the Pre- nursery, nursery and field operations in the management of permanent crop plants will be treated.

More detailed operations will be treated under each unit where each particular permanent crop is discussed.

Nursery Activities and Operations

Nurseries are places where seedlings are raised for planting purposes. In the nursery the young seedlings are tendered to develop in such a way as to be able to endure the hard field conditions.

Nursery seedlings become the planting material for plantations. Nursery seedlings are found to have better survival rate than seeds sown directly in the field.

This unit will review the various operations involved in the production of seedlings amongst other activities performed in permanent crop production.

Nurseries are of two types – Temporary nurseries and Permanent nurseries

Temporary nurseries: These are established in or near the planting site. Once the seedlings for planting are raised, the nursery becomes part of the planted site. There are sometimes called “flying nurseries”.

Permanent nurseries: These can be large or small depending on the objective and the number of seedlings raised annually. Small nurseries contain less than 100,000 seedlings at a time while large nurseries contain more than this number.

In all cases permanent nurseries must be well-designed, properly sited and with adequate water supply. Seedling production is a major expense of plantation agriculture.

Every effort should be made to produce good quality seedlings at a reasonable cost. To this end mastering the techniques of nursery operations is essential.

Choice of Site for the Nursery

When the site of a nursery is to be selected, four questions usually arise:

What is the type of the nursery?

Is it temporary or permanent?

What is the size of the nursery?

Is it large with over 100,000 seedlings per year, or

Is it small with 50,000 seedling capacity per year or less?

Seedling Demand

How big is the seedling demand? For example, a nursery surrounded by several development projects may demand huge amounts of different seedlings every year, whereas a nursery for small plantation/s may have a low annual seedling production.

Transport or distance from the nursery to places of seedling demand.

When these questions are answered, the nursery is sited where:

Good water supply source is available, e.g. near a river or a well. Because water is very crucial to the nursery, this is a determining factor.

Good soil source is available; as soil is bulky, it is needed in great quantities. Site soil must be at least free from salinity and alkalinity.

Site is well drained to avoid water-logging and be fairly safe from flood hazards.

There is shelter against prevailing winds: sites which have a natural shelter by vegetation or any other formation are preferred to exposed sites. If the site is exposed then it must be sheltered artificially.

There is good access road to places of seedling demand. This will ensure that seedlings can reach the site in good condition. Bad roads and long journeys reduce seedling survival to a great extent.

Labour is available or can easily be obtained and accommodated. Nursery work is labor-intensive and placing nurseries far away from residence areas will be very costly.

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Design of the Nursery

Having decided on the site and size of the nursery, the site is carefully levelled, fenced, and a shelter from the prevailing wind is established.

The nursery must be well designed. The nursery is divided into a suitable number of blocks. These blocks contain adequate roads among them. Blocks are normally labelled by letters, e.g. A, B. C, etc. or by Roman numbers: block I, block II, block III, etc.

Roads between the blocks should be wide enough to provide space for on-loading and off- loading and contain turning space with a minimum width of 5 meters.


Each block is further divided into 4-8 sections with paths among them. Sections are labelled by their respective block label followed by a small letter, e.g. Section Ia denotes the first section from the left hand corner of block I.

Each section is further divided into beds. The bed is the smallest unit in the nursery design. Beds are normally one metre wide and their length may vary from 6-10 metres.

Beds may be sunk in the ground at a depth of 30-35 cm below general ground level. In this case they may be laid with concrete, stone or bricks.

Also beds may be designed slightly higher than the general ground surface. In this case, the beds are surrounded by stakes, bricks or stones. In every case drainage in these beds is very important for seedling development and for nursery hygiene.

Beds are labelled by their blocks and section followed by Arabic figures, e.g. bed No. Ia1 denotes the first bed in section (a) of block I. Beds are separated by paths one metre wide to facilitate work and transport of seedlings by hand or wheelbarrow, watering and tending of seedlings.

In addition to these, the nursery design should contain adequate space for soil mixing (at least 5 x 5 metres). It should also contain a separate area for making compost. This is better placed slightly away from the nursery beds.

Size of the Nursery: The size of the nursery area stacked with containers (when containers are employed) and the total nursery area will vary with the diameter of the containers.

The relationship between the diameter of containers/polyethylene bags (from 5 to 15 centimetres) and the surface of the nursery area (in square meters) for the production of 100,000 potted plants needs to be determined.

For containers with a diameter of 5 centimetres, 240 square metres of beds are required.

To estimate the total nursery area, the area of seedbeds is multiplied by 2.5, to include road and service areas, and 100 square metres are added (for paths), based on the production of 2,000 seedlings per square metre of seedbed.

Therefore, in general: the total nursery area = (2.5 x area of seedbed) + 100 square metres and, for this example:

The total nursery area = (2.5 x 240) + 100 square metres

Not all nursery operations involve the use of containers. When bare-rooted planting stock is produced, the size of a nursery will depend, in large part, upon the “average” size of the planting stock and the level of production to be maintained.

Nursery Water Supply

Two aspects should be emphasized: (a) water quality; and (b) daily water requirement.

Water quality: It must be slightly acidic with a pH of less than 7, with dissolved salts less than 550 parts/million, and a conductivity of less than 0.8 mho/cm. Generally, the water must be fairly sweet and clear.

Water quantity: Adequate water of the above description should be supplied daily to the nursery.

The amount of water applied (at any one time) will vary with the weather conditions, the soil infiltration rate, and the size of the plant. During the period of germination, frequent “light” watering is required to keep the seedbeds moist, but not saturated.

As plants grow, the total quantity of water applied is increased and the frequency of application is reduced.

As a guide to estimate the quantity of water to apply in one month, the following calculation can be made:

Water quantity = water loss factor x E x area of seedbed.

Where: water loss factor = values between 1.2 and 1.4, averaging 1.3.

E = monthly Evapo-transpiration.

For example, assuming a water loss factor of 1.3, a monthly evapo-transpiration (E) of 0.2 meter and a seedbed area of 10,000 square meters, the water requirement for one month is:

Water quantity = 1.3 x 0.2 x 10,000 = 2,600 cubic metres.

Watering can is either by hand or through irrigation. Hand watering with cans, hoses fitted with spray-nozzles, or knapsack mist sprayers are methods used by small nurseries.

For watering containers or seedbeds in which seeds have been sown, a fine droplet size is essential. Otherwise, the seeds can be washed out of the ground or the seed covering material can be washed away and the soil surface will be consolidated.

Therefore, hand watering of the seedbeds is commonly done with a gardener’s watering-can or a knapsack pressure sprayer fitted with a fine mist-producing nozzle.

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Benadine Nonye is an agricultural consultant and a writer with several years of professional experience in the agriculture industry. - National Diploma in Agricultural Technology - Bachelor's Degree in Agricultural Science - Master's Degree in Science Education - PhD Student in Agricultural Economics and Environmental Policy... Visit My Websites On: 1. - Your Comprehensive Practical Agricultural Knowledge and Farmer’s Guide Website! 2. - For Effective Environmental Management through Proper Waste Management and Recycling Practices! Join Me On: Twitter: @benadinenonye - Instagram: benadinenonye - LinkedIn: benadinenonye - YouTube: Agric4Profits TV and WealthInWastes TV - Pinterest: BenadineNonye4u - Facebook: BenadineNonye

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