Kiwi

Normally, the productive vines of Actinidia are renewed annually, so the weight of the vegetation and its production rests entirely on the supporting structure. Hence the need for a more complex support system than the classic Superspindel system for apples, capable of providing greater support for both branches and fruit.

It is also necessary to take into account in the design calculations the imposing leaf apparatus that Actinidia develop and whose weight has a considerable impact on the stress that the system has to sustain (especially when the leaves are loaded with rainwater).

There are basically two training systems: pergola and an overhead system (tendone).

Two completely different approaches, practically two life philosophies, rooted in the unique behaviour of the kiwi plant compared to any other fruit. Let’s look at them in detail.

TENDONE (OVERHEAD TRAINING SYSTEM)

The tendone system is nothing more than a tangled web of wires and cables designed to build a support network for the vines and the resulting fruit. The post scheme is usually five metres in between rows and five metres in between posts, with supporting ropes at each transverse (variable diameter between 6 and 7 mm) and six lengthwise wires to support the vines (approximately one every eighty cm), with a diameter of 3 mm.

This solution provides the plant with a strong support system that prevents the vines from touching the ground and consequently prevents all the diseases that result from this, whilst also ensuring greater effectiveness in the treatments required for leaf health.

The kiwi hangs below the foliage but free from it, thus being able to ripen at its best while taking advantage of the shade of the leaves to avoid getting the ever-dreaded sunburn.

Last but not least, harvesting is considerably easier, given the ease with which the kiwi can be picked, placed at the best height for rapid picking by operators.

Then we come to the second training system, the ‘pergola’ system.

PERGOLA TRAINING SYSTEM

The basic principle is very similar to the “tendone system”, with the same number of wires supporting the vines (from four to six) but these are supported not by transverse wires but by galvanised steel brackets, varying in size and width according to the variety of kiwi (straight, curved, sloping for yellow, green or red kiwi).

The bracket must provide a high load-bearing capacity to meet the requirements of the plant and must be firmly and securely connected to the post with its specially shaped anchoring. The tension on the support wires is provided by the pullers of the end brackets, a metal structure that is much stronger than the intermediate brackets and capable of supporting the tensioning effort. The vines therefore benefit from the same support as the tendone, with the fruit developing particularly close to the ends of the brackets, thus the need for the appropriate bracket to be allocated to each variety.

The main advantage of this type of system is the management of the net, which remains accessible for seasonal opening and closing operations, an option that in the “tendone” system is compromised by the growth of the vines.

Another strength of this type of system is the ease of access along the row, between the pergolas, for mechanical equipment of varying heights (cab tractors, mechanical pruning bars, forklifts, hydraulic platforms for managing the annual winter closing operations of the nets or any extraordinary maintenance operations on them).

Last but not least, particularly on the new cultivars included in the Club, there are the regulations that require the quantity of kiwifruit per hectare to be reduced in order to increase their brix (sugar content) and dry matter, an assessment that therefore also involves the support system in addition to agronomic environmental variables.

Last but not least, particularly on the new cultivars included in the Club, there are the specifications that require to reduce the quantity of kiwifruit per hectare in order to increase their brix (sugar content) and dry matter, an assessment that therefore also involves the support system in addition to agronomic environmental variables.

An excellent example of this system can be seen in the video shot by our customer Riccardo Adami of Società Agricola Adami, who has been using the pergola in his system in Dossobuono (VR) for almost a decade now with excellent results. On the green kiwifruit he has used the two-metre curved brackets, obtaining a production of around thirty tons per hectare with an excellent sugar level deriving from the excellent insolation ensured by the pergola support, which allows light to pass through even below the leaf apparatus, increasing the quality of production. The vines are tied approximately every twenty centimetres, leaving fifteen shoots and cutting about fifty centimetres from the ground, a simple and cost-effective job that also guarantees the best management of the orchard.

In 2019, Riccardo decided to convert one of Valente’s old peach orchards back to kiwi, and the wide six-metre post scheme allowed him to try out the new 3.10-metre curved brackets.

These brackets have been developed specifically for yellow and red kiwifruit and have a less pronounced curvature than traditional curved brackets, which allows them to better support longer vines, making the plant look neat and tidy.