Mechanized harvest, from tradition to innovation

Olive cultivation is one of the traditional sectors of Italian agriculture with a capability to ensure production par excellence. The leading competitors of producers abroad are pushing the Italian system to acquire more modern technologies for optimizing harvesting to avoid damage to the trees. Many technological innovations have been developed to meet the needs of widely varied types of production

In olive cultivations, harvesting the stone fruit is the most demanding step from the financial and organizational point of view due to the need for considerable manpower, the limited time for performing the operation — especially if the olives are intended for high quality oil — and farm plots which are often small and weigh on the productivity of labor on the cultivation sites. Mechanization for rationalization of this phase can make it possible to lower production costs, especially for traditional olive cultivations and small plots which account for a considerable numbers of olive crops in the Mediterranean Basin. Traditional cultivations are often managed according to old methods, for example, the shape of the trees beginning with vase form, the absence of a trunk, and leaving three or four primary branches which then takes on a free form resulting from pruning, possibly every ten years, to facilitate alternative production. This type of cultivation produces high quantities of lampante oil, not used for food consumption, which must aim for higher quality possibly achieved through adequate harvest techniques.

More modern plantations with more than 300 trees/ha are sometimes affected by a level of mechanization not up to the potential of the orchard because of problems with investments to acquire more widespread technologies, especially for small producers.

In the present context of international olive cultivation, many countries are boosting their production, also those outside the Mediterranean Basin, and the current aggressive market policies pursued through stronger competition are becoming a priority objective. Technological innovation must be one of the objectives to pursue for crucial issues of efficiency of the resources deployed and the costs of production. Based on these assumptions are the new models referred to as super-intensive which feature plantations of up to 2,000 or more trees/ha with the advantage of great efficiency with mechanical harvesting continuously achieved through the deployment  of row straddling machines in use for some time for excellent results in work in vineyards. Equipping these machine with special modules adapts them for the harvest of olives. This system is based on the assumption that the integral mechanization of harvesting can guarantee maximum efficiency of costs of in olive cultivations when associated with techniques for controlling vegetation growth and production to meet requirements for the economic sustainability of the sector. The site on which these machines are used involve two workers, one driving the tree straddler and the other managing the trailer in which the production of the harvest is loaded. These conditions lead to a substantial reduction of harvest costs with full care of the product.

Though this model now presents a driven concept of mechanization, it does not sideline the use of conventional machinery for the harvest, most strongly represented by shakers which are now undergoing a new phase of development. An example is greater attention now focused on the materials used for the head tightening clamps. Aside from full or bored thermosetting materials, numerous alternative solutions have been developed by manufacturers such as filling them with compressed air or coating them with compound materials. Among the experiments conducted by academics is the example of the Mecaolivar Project at the University of Cordoba in Spain where a head with electronic control of the regulation of vibration frequencies has been developed and oil-filled clamp materials used.  

In general, heads with two tightening clamps have been shown to be more flexible because they can be used on differing sizes of trunks and limit the transmission of vibration at two points of contact. Three clamps provide better transmission of vibration to the tree while reducing the risk of damaging the bark and this becomes more binding for the size of the trunk.

At present, the range of shakers brought to the market is extremely wide, from self-powered models to reversed umbrella shakers manufactured to meet the requirements of the many types of olive cultivations. The great spread of these differentiated machines is the result of their high productivity performances and their maneuverability and reliability. The choice of self-propelled machines or tractor mounted models depends on initial investment capabilities and the related return of the investment. The selection of a small or big machine depends first on the size of the trees in the plantation for carrying out the harvest. The power available is usually an important factor for determining the efficiency of operations and machines with power of 70 kW or more are advised.

One of the requirements given most consideration is guaranteeing compatibility between the machine and the trees to make certain that the trees receive adequate vibrations from the shaker to maximize fruit yield and minimise damage of the trunk. A good machine must guarantee a yield of at least 80% of the fruit up for harvest. If the harvest is early to increase the quality of the final product strong vibrations and great mass are needed for acceleration beyond 200 m/s2. For the timing of the ideal shaker, what is prefered is the brief repetition of the single vibrations applied: two short repetitions are advised compared of a single one of the same duration. To be kept in mind is that damage to the tree is not caused by machines properly used but by the incorrect use of these machines, Damage can be caused by an operator with little experience leading to vibrations which last too long, a wrong application of the clamp on the truck or excessive consumption of the materials in use. Moreover, bad management of the plantation can play a vital role. An example is leaving pollen on the plants which makes the grasp of the clamp insufficient, inadequate or, still worse, not effective.

Where harvest off the ground systems resulting in low quality oil produced have been abandoned, interesting solutions have been developed to facilitate the work of operators and favor the trees, especially for small-medium plantations. These solutions include various types of combs and pneumatic air harvesters. In recent years, the progress of innovations has been applied to the development of self-propelled machines capable of operating on the crown of the tree rather than the trunk, especially for traditional plantations, designed for increasing production yields. The various prototypes created under the Mecaolivar Project are aimed at boosting harvest efficiency, which is difficult for trees with big crowns and difficult to manage from below.

Thus a brief examination arose for the aim of using machines adapted for modern type olive plantations and making progress for increasing performance combined the intention to innovate harvest systems for conventional plantations for an ongoing increase in quality. Basically, this is because olive cultivation is and will remain an unchangeable attraction unless there is growth.