This planting guide gives details on practises which are implemented at Rietpan Nursery. We are not consultants but wish to share with you what we do and what works for us.
Before you start your planning...
It is very important that you note that every effort is made on our part to supply you with trees of superior quality. We cannot, under any circumstances, accept liability for trees which are planted and then don’t flourish. Extreme care is taken, when packing the trees, to ensure that the roots of all the trees in the bags are intact. Due to the size of the operation it is possible that there may be some damaged roots. When taking the trees out of the packaging, we have to be informed immediately if there are any damaged roots. When planting bare rooted trees, a 5 – 10% loss is the industry standard. If there are more losses, it could and normally indicates a management problem.
The following are practises regarding planting and nurturing of trees which we implement and have found to be successful.
Pecan trees, along with almond and walnut trees, are known to be the most salt sensitive of trees grown under irrigation. Salts build up in the soil due to the use of fertilizers and irrigation.
Before considering planting pecan trees, water and soil samples have to be sent away for analysis. We find American laboratories, Brookside and Perry, to be very reliable for soil tests especially with regards to micronutrients. Water quality is very important. If using borehole water, the EC and salinity of the water is to be checked before embarking on purchasing and planting of pecan trees. Most boreholes in the Northern Cape, in our opinion, would not be suitable.
When finally starting the process of planting, there are some critical factors:
Plant as soon as possible: You need to be ready to plant from mid-July to end of August as this is the time that trees are harvested and packed. You will be notified when your order can be fetched and then trees are to be planted as soon as is possible thereafter. Leaving the packed trees in the sun or a hot warehouse is not an option as dormancy will be broken. The viability of the trees can be maintained by keeping them in a cold room – especially when there could possibly be a delay in the planting. It should be your aim to have finished planting by the time Spring arrives. Late plantings decrease your chance of success.
Late plantings decrease your chance of success.
Not even for a moment.
Do not leave the exposed root in the sun at all – not even for a moment. The roots must remain moist at all times and the tree should not lie with the root exposed while the hole is being prepared.
The soil must be deep and well-drained and the planting holes must be big and deep enough to accommodate the whole root system. We have dug holes using spades, TLB’s and augers. The bigger the hole, the more management there is but this probably allows the roots to expand easier. Presently we are using 250mm and 500mm augers to make the holes and then these are squared with spades.
Presently we are using 250mm and 500mm augers to make the holes
We apply our amendments after planting the trees in our orchards.
Do not put any fertilizers or soil amendments in the planting holes at all. All amendments, fertilizers and compost can be placed on top of the soil once the tree has been planted. We apply our amendments, normally gypsum or lime – depending on the results of the soil analysis – after planting the trees in our orchards. Following this we apply approximately 2 spades of compost (good high carbon compost and NOT rotted lawn clippings) around the base of every tree. We do not use any N, P or K fertilizers at all.
From the bag into the planting hole. When you are ready to plant the trees, remove all the packaging material and soak roots in water for an hour before planting them. We use Agri-K-Balance (“earthworm wee”) to dip the trees in. The rationale behind this is to colonise the roots with beneficial micro-organisms which assist with root formation. Agri-K-Balance is available when you fetch the trees but we must please be notified in advance if you wish to purchase.
When you are ready to plant the trees, remove all the packaging material and soak roots in water for an hour before planting them.
In both cases the tree has a high probability of dying.
Do not plant the trees too deep or too shallow. All our trees have a white line which is the planting line/ beginning of the root flare. Trees should be planted so that the white line is in line with the level of soil in the hole once the hole has been filled. It is important that the tree not be planted too deep, i.e that the planting line does not show at all. Neither can it be planted too shallow, i.e. that the root flare is above the ground. In both cases the tree has a high probability of dying. It may take a few weeks for the soil to settle and constant adjustments must be made. Do not neglect the newly planted trees – walk the rows and constantly adjust the depth to the level of the white line.
Do not plant the trees without an irrigation system in place. The use of a ‘water-karretjie’ or hosepipe normally leads to disaster as there is limited or no control at all. Planning of a pecan orchard starts months before the actual planting, and it is in this time that the irrigation system must be decided on and installed. This can be quite a long process and therefore timeous planning in necessary. Using a water-karretjie or hosepipe is not the way to cut costs!
Whether to use drip or micro-irrigation is a personal choice as both systems have advantages as well as disadvantages. When using drippers, be careful not to drown the trees – especially where the dripper is on the tree. For various reasons we prefer to use micro sprayers.
This can be quite a long process and therefore timeous planning in necessary.
This is a big killer of trees
Do not over-water. This is a big killer of trees and we have found the only effective way to monitor water is to install continuous logging probes. We use DSM probes which read the moisture levels at various depths under the ground 24/7. Much time is wasted wondering whether the soil is too wet or too dry and the probes are the only sure way of getting this information.
Do not allow weeds to be out of control. Pecan trees are not very good at competing with weeds. There must be very good weed-control. We use mulch around the trees, especially just after planting. Mulch (wheat-straw, maize stover or synthetics like Agriweave) creates a favourable microclimate for the roots. A mulch which is 15 cm thick, should enhance the growth of a tree by as much as 60%. Mulch controls weeds and also conserves moisture. Should you use organic mulches, it is important that there not be direct contact with the stem of the tree – it should be a few centimetres away from the stem of the tree. The areas in the orchard not immediately around the trees can be mowed. We do not advocate discing because of the constant disturbance of the soil profile and the exposure to sunlight. This practise will reduce the poor carbon reserves even further.
Pecan trees are not very good at competing with weeds.
Thys Fourie at Capstone Seeds can be contacted: firstname.lastname@example.org or 082 326 6797 for seed and advice.
The use of cover crops. We are doing some exciting work with regards to multi-specie cover crops. Our recommendation is to plant a mixture (turnip, radish, clover, oats, vetch and ryegrass) around the tree at the beginning of March. It will green in the winter and enhance the microbial component of the soil. Turnips and radishes are nutrient scavengers; clover and vetch are nitrogen fixers and oats and rye serve as a source of carbon. The heat of the summer causes the winter species to die off, leaving you with very little weed pressure. Thys Fourie at Capstone Seeds advised us on the mix of the cover crops. He can be contacted: email@example.com or 082 326 6797 for seed and advice. Presently we are experimenting with Summer cover crop and will keep you updated.
Be extremely careful when using weedicides. The use of weedicides is an easy fix but with a tail that stings. We do not recommend the use of Glyphosate as a weedicide in young orchards. We use Paraquat at times but are aware that this could also be harmful to the soil microbiology. Propaquizafop is used in our nurseries on grasses, especially kweek, with little adverse effect on the young trees. Uintjies/ nutgrass can also be a problem and to curb this we use halosulphuron or sulfentrazone. Weeding is probably best done manually using a hoe.
Weeding is probably best done manually using a hoe.
Pruning. Correct pruning of pecan trees is very important for the future shape of the tree and to prevent wind damage. Pruning must be done in winter when the trees are dormant. We suggest attending a practical course on pruning or employing professional pruning teams. Herewith are some of our ideas on pruning of pecan trees:
- Leaves are the factory where food is manufactured by the tree (95% of the dry matter mass of the tree is as a result of photosynthesis in the leaves). Each time branches with leaves are chopped off (pruned), energy is lost. Pruning should therefore be kept to a minimum.
- The trees should have the shape of a Christmas tree … like a triangle. There must be a central leader with staggered spiralled scaffold branches.
- In the first season you aim to create a central leader with a trashy trunk. No lateral or scaffold branch should be allowed to get longer than 20 – 30 cm. Upon reaching this length, the branches should be pinched. In the winter at the end of the first season, the central leader should be cut back by a 1/3 and the scaffolds should be thinned out and organised.
Foliar feeding. It is a well-known fact that pecan trees are very ‘zinc-hungry’. It is vitally important that foliar feeding is done on a regular basis to address this.
We trust that you will get much joy and satisfaction in your endeavour. Please remember that orders for next year’s season have already opened and you should place your order sooner rather than later.