Grove Layout
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OLIFAX - 3A

OLIVE GROVE LAYOUT

Olive Agencies Information Services

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Grove layout is probably the most long term decision you will  make concerning your olive grove. The trees will stay in the aspect and spacing you select for them for many years to come. There are a number of factors which  determine the physical layout of your grove. The purpose of this OLIFAX is to outline and explain these factors so that you can decide on an effective  layout.

ASPECT

When planning the aspect of your grove you must keep in mind the fact that light and air penetration will increase the tree's health and  crops. To achieve maximum light penetration into each row and each tree, the rows should be planted as close to a North-South direction as possible. That is, if you were driving a tractor up or down a row you would be facing either North or  South. This aspect allows the light of the sun to best penetrate the trees as it  moves across the sky. The aspect may need to be adjusted slightly to account for slopes or contours, but as a rule, try to keep as close as possible to North-South.

TREE SPACING

Over the past few decades there has been ongoing research  throughout the international industry regarding the most viable tree spacing for  irrigated olive groves. However, as more and more trials are coming of age and  results are being published, it is becoming increasingly accepted that the most effective spacings for an irrigated, mechanically harvested olive grove range  from 250 to 300 trees per hectare.

The tree spacing in these irrigated groves ranges from 8m x 5m (250 trees/ha) to 7.5m  x 4.5m (296 trees/ha). Although some irrigated trials have shown increased crops from more densely planted groves in early years, researchers generally agree that the 250-300 tree/ha groves are more economically viable in the long term. Growers looking at shorter term (10 years or less) olive groves and/or dynamic plantings with increased crops per hectare in the early  years can gain further information on the denser plantings from Australis Plants. Research is being conducted for densities from 400 to 1,250 trees per  hectare in Spain, Italy and Argentina using a range of mechanical harvesting equipment.

Recommended spacing for olive trees is the traditional 5m x 8m (250  trees/ha). Although not quite as dense as the 300  trees/ha, the 8 metre row spacings give enough room for the movement of whatever size mechanical harvesters are available at the time of harvesting, and the 5  metre tree spacings give room for the opening of a fruit catching umbrella. Following is a list of factors which need to be assessed when deciding on a tree  spacing for your grove.

Irrigated or Non-irrigated?
The majority of olive groves being planted outside of the Mediterranean have some form of irrigation system. The main advantages of irrigation are improved tree health and resulting increased crops which make the grove economically viable. Irrigation allows trees to be planted closer together as they are not competing with each other for natural rain water. If you are not  planning to irrigate your grove, you will generally need to plant your trees on a spacing of approximately 9m x 9m (120 trees/ha). Naturally this spacing will vary depending on the amount and season of rain received in the region, but broadly speaking, 9m x 9m is a satisfactory spacing for non-irrigated groves. This gives each tree 81m2 of land from which to source its necessary water and nutritional needs.

Mechanically Harvested or Hand Picked?
Your choice of harvesting method directly affects the site and spacing of your trees. As mentioned above, Olives  Australia recommends an 8m x 5m spacing to allow for mechanical harvesters such  as an Enviroharvester or Orchard Machinery Corporation's Catchall III to work efficiently in the rows. There are also smaller tractor-mounted shakers which  can work in narrower rows but don't forget that increased light and air penetration into a tree will improve the tree's health and crop. There are also some harvesters which actually consist of two machines and two operators, one  machine drives down each side of the tree row. The first machine shakes the tree  while the other is a catching machine which collects the fruit. These machines can also work in narrow rows. However, just because there are harvesters that can work in a narrow, say 6m x 3m tree spacing, doesn't mean that your trees will necessarily produce their best long term crops at this spacing or that such  a machine will be locally available at your harvest time. Unless you are planting many hundreds of hectares and will purchase your own harvester, you  need to consider the type and availability of the mechanical harvester/s most  likely to be working in the density of groves near yours.

The slope of the ground in the grove also effects the  efficiency of mechanical harvesters. According to OMC in California, a slope of up to 25 degrees (maximum) is suitable for their Catchall III harvesters if there is a firm surface underneath. Groves on slopes greater than 25 degrees  currently need to be hand picked.

If you are planning to hand pick fruit for table olive processing then you may choose to plant your trees closer than a mechanically  harvested grove. A spacing of 6m x 4m (416 trees/ha) could be planted. However, it is still recommended that you plant on approximately 8m x 5m to allow for the invention of non-fruit-bruising mechanical harvesters suitable for table olive picking in the future, and again, to allow light and air penetration. Also, after eight or ten years of growth, a row spacing of 6 metres will not allow room for the movement of normal sized vehicles for carrying the  harvested fruit in most varieties.

Drainage
Although grove drainage is not the topic of this sheet, there are two main points to consider.  Firstly, too much water is the worst enemy of the olive tree. Your soil type and drainage system must allow water to get away efficiently both above and below the ground surface. Secondly, you need to protect against erosion in the grove.  Make sure your grove layout balances all of the points on this OLIFAX without  causing extensive erosion to your property.

Which Pruning Method?
The  shape to which you prune your tree is naturally going to effect how close your  trees can be planted together. If, as most growers choose, you are pruning in  the vase shape then about 250 trees per hectare is fine. If on the other hand  you are planning to prune monoconically (Christmas tree shape), then you may choose to plant slightly closer together. (See OLIFAX 9 for more  details on this monoconical method).

 

MARKING OUT THE GROVE

 

Many people wonder what is the easiest method to mark the  actual tree sites onto a paddock. Although we've planted over 28,000 trees on our own nursery property for propagation purposes and many thousands more in a  private grove, we've also consulted to a number of our large commercial clients.

Remember that your initial marking of the rows and tree sites  is not the final one. It is simply a rough marking to show where to spread your manure, crusher dust and possibly lime on each site, after which you will be  deep ripping the rows and thereby destroying any accurate marking you may have done. However, it is worth having fixed end-of-row markers which are positioned out of the way of ripping machinery as they will be a permanent row guide  through all stages of land preparation and planting.

There are many ways of marking tree sites. In reality it comes down to how accurate you want to be. Some growers mark their 8 metre row spaces with brightly coloured stakes at each end of the row and then simply rip  backwards and forwards between them. Others do the same but run a stringline  between the stakes to mark various points along the row with additional stakes  to guide the ripping machine even more accurately. Large groves are designed by  surveyors able to give perfect tree and row placements.

Once the land is ripped, some growers simply pace out the 5  metre tree sites along the centre of the ripped area (This method will not give  you an accurate and tidy grove). Others will again run a string line or use surveyors to get the rows exactly straight. Some use a tape measure to accurately pinpoint each 5 metre tree site (Generally a two person job). Another option is to use a long length of light gauge fencing wire or multi-strand stainless steel cable on which you have already marked the 5 metre spaces with a  bright paint or electrician's tape. If the row is very long, this wire can be pulled tight with a tractor or winch. The 5 metre paint/tape marks could expand  and contract a bit with different tensions on the wire but it does save a lot of measuring.

When fixing tree positions on hill country, the rows will often  not line up due to the distances gained or lost over the undulations. You may then choose to sight your rows by eye from a fixed point on the row. A second option is to use a surveyor or surveying techniques and equipment to fix the exact tree positions, despite the terrain.

Most growers find it best to use their permanent stake to mark each site prior to planting. The trees can then be planted in the hole beside the stake in such a way that they are growing towards and up the stake. Once the irrigation and stakes are in place, four people should be able to plant at about 150 trees an hour. Start with two people putting the trees at each site with a vehicle and trailer, one person digging holes and one person planting. When the  two with the vehicle have placed a few hundred trees they too can start  planting. This team with one person digging holes and three people planting works quite efficiently. It is then essential to thoroughly water the tree very  soon after planting.

While your final method is up to you, we hope this summary sheet has given you some helpful hints.

All the best with your planting.