Olive Cultivation – Farmlands

How to plant and cultivate olive trees

Olives are an ancient fruit from a blessed tree, encompassing various health benefits, alongside being incredibly nutritious, and in tandem holding remedy for many ailments. The olive tree, its fruit and its oil has been praised by God and his prophets.

Olives are very high in Vitamin E and hold some powerful antioxidants. Olive oil is produced from olives which contain healthy fats, which can be used for cooking and is most essentially used as a condiment or dressing for salads, including the olive fruit (table olives).
To grow olives, be it in the form of a large farm, garden or simply an indoor plant, there is a certain associated knowledge.
Below you will find the information and certain guidelines in regards to olive cultivation and production.

Land is the foremost consideration for growing anything, let alone olives. Land for growing olives needs to be chosen carefully.

Olive tree prefers fertile soil with adequate moisture, so that it can give sustainable high yields for many decades to come.
Optimum pH is around 6.5.
Olives prefer drained soil, where water can easily runoff, hence, avoiding rainwater stagnation.
Exposure to direct sunlight is necessary.
Flat surfaces are preferred, where cold currents can escape easily.
In order to avoid various fungi on olive grove, the soil must be kept fallow (plowed but left unseeded during a growing season) for around 3 or 4 years; before planting young olive trees. Alternatively, the field can be planted with a grass mixture for a couple of years and then cleaned.
Deep plowing (around 20 inches deep) is favorable in destroying perennial weeds soil fluffing, which contributes to development of better root system.
Soil testing, and adding 20-30 tons of manure per hectare as needed.

Water is life and hence an essential component of any plant. However different plants have varying amount of water requirements.

The olive tree is resistant to drought but responds well to a benign supply of water by any good method. As well irrigated trees produce higher yields.
Alternate bearing phenomena can be mitigated through well-designed irrigation system.
In general olive trees cultivated for oil require less water than for table olives. However, excessive irrigation should be avoided.
40-70% ETC (crop evaporation & transpiration)
Drip irrigation recommended for sloppy soils and sprinklers otherwise.

Growth and fruit production timeline for olive trees can be around 4-5 years and will eventually continue to eternity. Olive tree is eternal in a sense.

The olive tree can attain a height of around 4-20 meters or more. Olive tree trunk is smooth on young trees and bumpy on older ones.

Maximum temperature without causing damage is around 40^o C.

Maximum cold temperature is around -7^o C, but cannot be sustained for long by olive trees. But a certain amount of cold is necessary for fruit development.

Temperatures between -7^o C & 40^o C is suitable for olive trees, in tandem with other benign conditions.

Proper planting is essential

Field Markings for plantation, digging a hole of around 20×20 inches.
Seeds must be planted at the same depth as nurseries (from where young plants were brought from).
The surface soil of the pit must drop below the ball of the seeding.
The planting of seeding in areas where no frost is reported, starts from late fall (November to February). While in areas with frost, the planting starts in early spring, when even the last frosts have passed.
Average distance between plants should be around 20×20 ft or 6×6 meters. Dense planting rather than sparse results in roots overlap and mechanical harvesting problems. Distance between trees is also required to achieve a desired canopy shape.
The propagation of olive tree by seed or asexually is relatively easy, albeit plantation through seed is bit more complex. The olive tree is asexually propagated by root suckers, cuttings and grafting. Elect cutting or grafts in order to achieve product uniformity and quality.
Professional growers benefit from a tree that is a combination of two distinct plant tissues, the root stack and scion.

Pollination

Most varieties are self-fertile, hence a single tree is sufficient. Pollen from anthers (male part) is transferred to stigma (female part) of the same tree.
Pollination is primarily carried out by wind.
Research findings recommend that growers plant at least 3 varieties in close proximity to promote cross pollination, which has been found to boost yield by around 10%.

Soil pH and calcium content affect the absorption of some nutrients that are supplied by fertilizers.

Optimum pH is around 6.5, but the average olive tree can produce fruits at soil pH of 5.5 to 8.

Lime is often used for correcting soil pH (consult local licensed agronomist).

Minimum acceptable nutrients rates after chemical leaf analysis are 1.5% of Nitrogen, 1% for Phosphorous and 0.5% for K.

Nitrogen is most important and is necessary for germination & production of olives. In nitrogen deficiency leaves are much shorter and do not turn dark green.

Fertilizers

A common fertilization scheme involves adding 4-7 kg of N-P-K 11-15-15 fertilizer in every adult tree once or twice a year. The most suitable period is during fall and winter in non-irrigated areas. Although organic fertilizers are preferred.

Fertilizers can be added at a radius of 2-3 ft from the trunk, so as to avoid concentration in any particular spot, as every land is different and have varying requirements.

Organic matter in the various stages of decomposition (especially as humus) is beneficial in many ways. It improves soil condition such as consistency in light soils and texture of heavy soils, pH adjustment, maintains soil moisture, increase soil capacity and soil micro-organism and nutrient absorption.

During the autumn, manure slurry can be provided and incorporated into the soil. In olive farms with no irrigation and no frequent rainfalls, many farmers provide 10-20 tons of manure per hectare every 2 years. Conversely, in well irrigated areas this is performed every 3-4 years. hence well irrigated trees require less maintenance.

Sufficient calcium levels are important for a healthy olive tree, as calcium reduces susceptibility to disease. Most common symptom of calcium deficiency is chlorosis (leaves turn pale yellow or white). Calcium deficiency is often corrected by adding 6-7 kg of calcium oxide per grown tree.

Magnesium and Boron are also important for proper fruit development. Magnesium is the central part of the chlorophyll molecule, while Boron plays a vital role in the metabolism and transport of glucose. {In many cases, if farmers diagnose magnesium or boron deficiency in the middle of the vegetative period, they often apply foliar fertilizers (11-00-16 MgO, 20.5% B)}

Before applying any fertilization method for olive groves, physical properties of soil needs to be checked; such as soil texture, soil permeability, etc. and the amount of nutrients available.

Climate is an essential and predominant factor for the growth, survival and quality of any type of plant, as different plants require different climatic conditions to thrive. Olive tree in essence is a pretty resilient plant by nature but nonetheless does have its preference and gains from benign weather.

Olive prefers the somewhat Mediterranean climate, where mild winters are followed by sunny springs and hot summers.
Average annual temperature should be around 15 to 20^o C (especially for olive farms and groves).
Maximum temperature sustained by the olive tree is around 40^o C, without causing any impairment.
Minimum temperature for the olive tree is around – 7^o C; however, its only indicative as resistance of olive trees in cold climate depends on several other factors as well, such as the speed by which the temperature drops, length of frost, cold winds, humidity, germination and health of diverse tree varieties and relevant weather conditions.

Production yield

Most advantageous harvest time for olives can vary, depending on the environment and weather conditions, olive tree variety and cultivation method adopted.
Picking at the right time comes from knowledge & experience and can give grower a competitive edge in terms of production yield, organoleptic characteristics, color, taste, aroma etc.
Generally high temperatures during the fall result result in early ripening & vice versa.
The average olive production of a mature olive tree ranges between 50-200 pounds (20-90 kg). however, exceptions can occur like a yield of 900 kg for a single tree. But to achieve above average yield, olive tree needs to age at least 30-40 years old.
Irrigated olive trees reach their productive peak earlier, than otherwise.
Harvesting can be done by hand or through sophisticated machines of all sizes. Machine harvesting is inherently tricky on sloping land.
For Olive Oil, harvested olives needs to be transported to mill immediately, otherwise they may face risk of quality deterioration.
On average 3 to 7 lbs of Olives yield 1 pound of olive oil.

Pruning

As with majority of fruit trees, olive reacts positively to pruning.

Pruning to create a strong trunk & crown frame (this allows the tree to withstand heavy loads & winds).
Pruning also helps reduce tendency to alternate bearing.
To ensure adequate quality and quantity and prompt production of new fruit bearing wood & to facilitate harvest and application of plant protection programs.
It also helps extending the productive life of olive grove & aid in removing dead wood.
Pruning of olive tree takes place immediately after harvesting the olives in areas where there is no frost, otherwise it takes place during spring (march- April).
When pruning, keep in mind that olive fruits can only grow the year before. In a few words, purpose is to remove the old growth, while trying to restrict a tree from becoming too big or dense; hence new growth will be promoted. Normally the base and lower branches, which usually has no fruit bearing prospects and hence, no value. Thereafter, clearing the center of the tree, so that sunlight can penetrate to inner parts of the tree.
Sunlight penetration is extremely important for fruit growth and quality production.
Old, broken and deceased branches must be detached.
Pruning once or every 2 years is sufficient.

Alternate Bearing

Alternate bearing is a tendency of some fruits to produce much greater than average crop in one year and much lower, the following year. Olive trees have a strong tendency for alternate bearing. A large production in one year removes most of the various carbohydrates, organic nitrogen components and other essential nutrients, making available stock insufficient to produce new crops for next year.

Some farmers believe that by supplying olive trees with excess nutrients in year 1 or 2, alternate bearing effects can be minimized. However, research have proven that summer pruning and sophisticated irrigation are some of the ways for partial normalization of fruit production.

Threats

Olive Tree Diseases & Pests

Crown Gal is caused by agro bacterium tumefaciens and it usually concerns young trees. The most common symptom is tumors that appear on the roots, just above or below the soil line. Infected trees with many galls will gradually become unable to transfer water & nutrients to upper parts of the tree. Consequently they slowly become weak and finally die. This bacterium can survive for many years in soil.

Verticillium is a very serious fungal disease, caused by verticillium dahliae. In short the first symptom is that the olive tree leaves start to curl and discolor. The infection than spreads to other parts of the tree (root system), after a few years it may result in the death of the tree. The pathogen may live in the soil (as spores) for 20 years or more. Hence, growers must be careful when growing trees on a chosen field or ground (soil).

Other olive tree diseases are cercospora leaf spot, peacock spots and olive anthrachose, etc.

Dacus Oleae (olive fly), the olive fly hits mainly the olive trees in the Mediterranean region and can diminish the olive tree production in a few weeks. The small fly feeds on olives. The main symptom are spots that appear on the flesh of olives. This is where a hole is made and eggs are laid by flies. It can destroy around 60% of olive production and affecting the quality of of the remaining olives. In addition, the acidity of olives is increased by a high margin. In most countries hydrolyzed baits are used to inhibit increase in olive fly population.

Finally

Start with good research and knowledge of your surrounding land and weather conditions and access to water. And pursuing plantation with caution and patience and using organic and natural methods for best production.