How To Plant and Manage a Citrus Orchard
An Orange Orchard
Citrus species are grown principally for the juices of their fruits and for local consumption. They are rich sources of vitamin C. The Citrus group comprises of very important species that are of economic and medicinal importance as well being nutritious. It is produced all year round. It is in international trade and exportation could bring much required hard currency to the country. Production of Citrus requires specific skills which can only come by training.
This article will give you details specific to citrus production. You will be familiar with production details which apply to all members of the Genus Citrus.
At the end of this article you should be able to:
- to select a site for citrus production
- prepare a nursery for citrus
- prepare a seed bed
- provide rootstock
- prepare budding bed and carry out budding
- transplant to field, manage the field up to harvesting and storage
You should prepare a rich deep loamy site for your citrus orchard, however, citrus will survive and do rather well in soils too shallow and poorly aerated for other tree crops to survive. On the other hand, Citrus trees may be badly injured in soils a little more shallow and wet where mango for example would thrive. Any site selected should be level or only slightly sloping. It should also be protected from strong winds either naturally or by the establishment of windbreaks.
The Genus Citrus comprises of species in which sweet orange, Grapefruit, lemon, and Lime are included.
Nursery practices are discussed in detail in this article. In addition to what you will learn in that article on how to prepare nursery for plant and tree crops, you will need to select an area with good shelter from winds. In areas of heavy rainfall, a gently sloping ground must be chosen for thorough drainage. You must avoid water logging conditions. You should look for deep and well-drained soil.
Seed bed Preparation and Sowing
Cultivate the soil deeply and then apply fertilizers as a base dressing as follows:
- Super phosphate 60g/m2
- Sulphate of ammonia 30g/m2
- Potash 30g/m2
Your seedbed should be about 1.2-2m wide and as long as is practically convenient for you. You will need to raise the bed to some 15cm above the surrounding ground level. You should be careful about using organic manure because it might introduce disease organisms. You should sow your Citrus seeds in either seedboxes or in nursery beds as single seeds spaced at 3 x 6 cm. You should pick out the seedlings when they are 3 to 6 cm in height into care baskets or poly bags which you have filled with fertile topsoil.
RootStock Seed Planting
Plant the seeds of the desired rootstock. Rough lemon seed is usually used (sour orange can be used also)and planted in rows about 25cm apart on the bed and about 8cm within the row. You may drill the seeds and thin to about 8cm apart later.
You will need to mulch the seedbed with groundnut(peanut) husk or some other suitable material. Apply plenty of water but avoid undue moisture otherwise fungus disease might attack the seedlings. Transplant to budding bed at about 4 months after sowing.
The Budding Bed
Set seedlings in rows 45cm apart and 25cm within the row. Mulch heavily with dry grass leaving a small area around each seedling to reduce the danger of disease infection from the mulching materials.
Water the plants regularly. Each plant should get about a gallon of water per week. Apply about 149 of sulfate of ammonia and 149 of muriatic of potash per seedling every 8 weeks. After 7-12 months on the budding bed, the seedlings are ready to be budded.
Budding is better done at the beginning of the rains or at the end of the rains but not at the height of the rainy season. This is because disease organisms grow very easily during the rains.
You may bud your tree crop during the dry season provided watering or irrigation facilities are available. The advantage of budding in the dry season is that you can regulate the amount of water the budded trees receive.
Budding is carried out in the cool hours of the morning or in the evening at a height of 25 to 30 cm from ground level on the prepared seedling rootstock. You should avoid budding during the hot hours of the day and during heavy rains. Practice regular care on your budded stocks until they are old enough for transplanting into the field.
The Most Popular Methods of Budding used in Citrus are:-
1. Inverted “T” budding
2. “T” or Shield budding
3. “Side budding”, similar to side grafting in mango has just been discovered in IAR, Samaru. (It is yet to be published but it is about 75-80% successful, all other things being equal).
You may use two methods in transplanting your tree. The “bare-root system” or the “ball of earth” method.
The “ball of earth” method is better because since a lot of soil is left on the roots, transplanting shock is greatly reduced. If the “bare root system” must be used because of transport difficulty with the “ball of earth” method, the roots must be dipped in a “slurry” mixture of soil, clay and water in a suitable consistency.
You should plant your seedlings into the orchard at the beginning of the rainy season (May – June). Dig your planting holes 1m x 1m x 75cm or as appropriate about one week before transplanting if possible.
You should half-fill the planting hole with top soil mixed with rotten compost or topsoil with high organic matter content. Put the seedling in position with one operator holding it upright and in position in the hole, and the other operator being responsible for arranging the roots properly (for seedlings planted with naked roots). After proper filling, the second operator should consolidate the soil around the seedling to ensure that air pockets are completely excluded from the planting zone.
You must allow adequate planting distances which are essential for economic productivity of Citrus. You should use recommended spacing for Citrus which is 10m x 10m.
Orchard planting is a very delicate and extremely important operation. Those to do the planting should be selected on the s of carefulness and be trained in correct ways of planting.
You will be wise to apply Nitrogen, phosphorous, potassium and magnesium. Where the trace element has been found to be deficient (they are not normally deficient) by foliar analysis, for example, the elements, manganese, molybdenum, Boron etc, should be supplied if necessary by spraying.
You should ensure that the recommended fertilizers by the Federal Ministry of Agriculture and Natural Resources for your zone are used.
Citrus requires little pruning, over-doing it is likely to result in reduced yields. You therefore limit to removal of dead wood, overly vigorous branches and suckers.
Sometimes it might be necessary for you to remove too much dense growth to open up the trees for sunshine and wind to dry the trees in areas of heavy rainfall.
This will reduce the infections by gummosis and foot rot fungi.
Citrus trees deplete soil water throughout the year; long water deficits therefore impair tree growth and fruit set. However, some short periods of water deficit is required for flower initiation. Even though the drought may have lasted just long enough to start flower induction, you will find that oranges will not blossom until the rains begin or you irrigate the orchard.
Citrus trees tend to drop their fruits excessively because of great daily water deficits especially parthenocarpic fruits (fruits which develop without fertilization) for example, Washington Navel Oranges.
Parthenocarpy is the term used for a situation where fruit development takes place without fertilization. These fruits are said to be parthenocarpic.
Examples of these in Citrus are Washington Navels, sweet orange, and marsh seedless grapefruit.
It is believed in the Citrus industry that when seeds are processed with fruits in the extraction of juice, the natural sweet taste of orange is tampered with. A situation where there are no seeds in the fruit is a welcome development. Having to remove seed mechanically or manually before fruit extraction attracts extra cost.
Harvesting and Storage
Citrus begins to bear fruits from 3 to 5 years after planting in the field depending on the species, variety and method of propagation. Vegetatively propagated materials comes into fruit season earlier than seedlings.
In Citrus, you will discover that the color of the fruit is green when fruits are not mature in many cases (Nigerian Green Sweet is an exception). On maturity, the fruits begin to ripen during which period the colour turns yellow.
You should harvest when mature fruits with considerable green will ripen if you store at 600 F without artificial treatment(like ethylene). Only fruits that are ripe at harvest keep at low temperature like 450 F.
It is very important that you do not bruise the fruits while harvesting, otherwise molds can gain entrance and cause foot rot and this is the greatest source of loss after harvest.
Citrus fruits are easily perishable after ripening. To ensure that fruits are not lost through over-ripening, fruits should be harvested immediately they are ripe and delivered to consumers, processors or retailers. In some cases, you may need to atore your fruits for some time while awaiting markets or transportation to distant markets. Under such circumstances, you may need to harvest the fruits a short time before full ripening, the time interval between harvesting and full ripening depends on the length of time the fruits are to be stored or the length of time required for transportation.
When fruits are destined for distant markets, you should harvest when they are physiologically mature but before ripening, such fruits generally ripen enroute to the market or they are treated with chemicals (ethylene, etc) to ensure uniform ripening.
Pests and Diseases
You will experience a number of insect attack on your Citrus. These include scale insects, aphids, mealy bugs, mites, fruit moths, beetles and others. You will need to use insecticides. However, in spraying Citrus with insecticides you should take caution. Certain persistent insecticides such as DDT could do more harm than good as they kill both pests, predators and parasites. Please consult a pecialist before the application of chemical sprays to Citrus.
Citrus diseases may be caused by virus, bacteria, fungi, algae, nematodes and plant parasites. Citrus plants are also known to suffer from a number of deficiency diseases.
Major diseases of Citrus:
1. Tristeza- This is a virus disease of Citrus. It is not controllable but preventable by using the right rootstock like rough lemon.
2. Anthracnose- Major symptoms are leaf blight, twig blight, and staining. It can be controlled by spraying with copper fungicides, proper sanitation and you could use disease resistant varieties if available.
3. Scab- It is caused by fungi. The main symptoms are whitish scabs on leaves twigs and fruits of Citrus. Major methods of control are farm sanitation; you may spray with fungicides such as Captan and Bordeaux mixture.
4.Footrot or brown rot- This is simply known as Citrus gummosis. It is caused by phytophthora sp. It kills the bark on trunk and roots which eventually kills plants. Control is to treat plants with effective fungicides.
1. Sooty mold
2. Algal leaf spots
4. Mineral deficiencies
In most cases, you do not need to worry much about the minor disease adequate farm sanitation will keep them in check.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.