by A. Zaid and P. Klein
Date Production Support
Programme
This chapter highlights, in detail, the various technical steps needed to ensure the proper establishment of a date palm plantation and its management.
It is worth mentioning that since accurate information was available to the authors from their own experience in Namibia (Southern Hemisphere), it seemed appropriate to base the technical calendar on this region (Figure 89). Nnorthern Hemisphere readers could keep the difference in seasonal times in mind (i.e. fl owering is during July/August in the Southern Hemisphere and February/March in the northern hemisphere; fruit maturation and harvesting are during September/October in the Nnorthern Hemisphere and during February/March in the southern hemisphere).
November
- Acquire the required amount of microsprayer supports (at a rate of 3 per plant);
- Prepare the required amount of protection units made of wire mesh and a shade net (1 per plant). No plant should be planted if no protection unit is available;
- Plant wind breaks (at least one year in advance); use Beef wood (Casaurina cunninghummiana or Casuarina glauca) which is characterised by rapid growth, high level of drought, and salt tolerance.
December
- Debusing and levelling;
- Layout of lines and rows;
- Ripping (± 1.2 m) in both directions on the rows;
- Install the irrigation system (secondary and tertiary pipelines only);
- Mark the exact position of plants;
- Dig holes (0.6 m³), if soil has been cross ripped or 1 m³ if soil was not ripped, and leave open till end of December;
- Try to localise old, well matured manure or any other organic material (i.e. maize hay, wheat straw, etc.) that will be used the next month.
January
- Place the irrigation supports (3 per plant) and connect the micro-jets (or drippers). The irrigation schedule is presented in chapter VII;
- Mix the well matured manure (3 kg per plant), gypsum (if needed) and NPK fertilisers with the soil removed from the hole;
- Put the mixed soil back in the hole;
- Start the irrigation cycle 2 to 3 times to allow soil to settle. The decomposition of manure will be initiated. When gypsum is applied, a short term leaching programme should be followed before planting;
- Enough time (4 to 6 weeks) should be allowed before planting to avoid the nitrogen negative effect period.
Fertilisation at planting:
The following amounts are to be used per planting hole:
- 3 kg of old kraal manure (± 3 spades full);
- 2 kg of gypsum (if necessary);
- 700 g double superphosphate;
- 500 g potassium chloride (or 625 g potassium sulphate); and
- 0.25 kg ammonium sulphate (and another 0.25 kg six weeks later).
February
- Tissue culture plants have been in the nursery for the past 8 to 12 months (depending on variety, their original size at reception from the laboratory, and on the care provided by the farmer). The plants should have been well irrigated (twice per week during winter and 3 times per week during summer; a close monitoring is to be ensured in case the substrate is made of bark), and fertilised according to the following programme: Mix 5 litre of SeaGro (5.5 %, 0.75 %, and 1.6 % of N,P,K,respectively) with 1,000 litres of water and apply at 140 ml per plant. Repeat once every two weeks until transplanting into the fi eld. For practical purposes, the plants could be irrigated with the solution by replacing a normal irrigation schedule;
- Select your planting material at the nursery; only plants with at least 4 pinnae leaves are to be transplanted in the fi eld;
- Inspect your plants and make sure they are free of diseases and pests. In the future plantation, use the Integrated Pest Management Approach (manual or mechanical weeding, light traps, etc.);
- Review and ensure the identifi cation of each plant; where different varieties are being planted, use different colour labelling for each variety;
- Each block, row and line is to be labelled. A map of the plantation (variety composition) is to be kept in the offi ce (and/or at home).
March
February and March are the best months for planting (no wind, no extreme temperatures and the average humidity is about 40 %). Let us suppose that our planting date is March15:
- Another irrigation before planting is advised. Irrigate to fi eld water capacity;
- Recommended spacing is 10 × 8 (10 m between rows and 8 between palms in a row); 125 palms per one hectare will be the planting density;
- Planting should be done early in the morning to avoid transplanting stress, and irrigation should be done immediately after transplanting;
- Bags should be cut from the bottom and progressively removed upwards, while the soil is put around the palm's substrate (to avoid roots damage); all distorted or damaged roots are to be pruned;
- The leaf base of the palm should be clearly out of the surface of the soil; planting must be to the depth of the plant's greatest diameter;
- A basin of 1.5 to 1.8 m in diameter and 20 to 30 cm deep is to be built for each palm. Hay or wheat straw is to be used for mulching;
- Irrigation cycle depends on the location. However, we recommend (from planting till end of August) 2 hours per cycle and twice a week. From September till March the next year it should be increased to 3 cycles per week and 2 hours each cycle. This irrigation calendar supposes the use of three drippers or microjets per palm at a rate of 32 litre/hour each. The palm will hence receive 96 litres per hour.
- At all times, the soil near the newly planted palm should be kept moist through light and frequent irrigation;
- The irrigation cycle is to be monitored (use tensiometers if possible), and frequent check-ups are essential to ensure the proper functioning of microjets or drippers;
- No leaf pruning is to be practised during the first two years (only leaves that touch the ground could be removed);
- The required number of male palms (5 for each ha) are to be planted separately in one block, preferably not in a windy spot and close to the pollen workshop;
- Weeding is to be properly implemented;
- Next year March: if needed apply 5 kg of gypsum per palm.
April
- April 15 (4 weeks after the planting date): apply 250 g potassium chloride per palm;
- April 25: apply if needed 2 kg of gypsum per palm;
- Apri 30 (six weeks after the planting date): apply 250 g ammonium sulphate per palm.
May
- May 15: apply the second 250 g potassium chloride per palm;
- End of May: assess your survival rate (should be at least 95%).
June
- June 15 (six weeks interval): apply the second 250 g ammonium sulphate per palm;
- Once the first year after planting is over, a fertilisation programme is to be applied till the first fl owering year (year 4 or 5 depending on variety, location and provided care). Full detail about the fertilisation programme can be found in Chapter VI.
July
- No offshoots should be left on a palm; they must be removed at an early stage to ensure vigorous growth and early fruit production. Removal of offshoots should be done twice per year (July and December). Make sure that the attachment point between the offshoot and the plant mother is treated with copper oxychlorid (use DEMIL DEX at 500 g in 25 l of PVA paint).
- After 4 years, the farmer must implement the following technical calendar.
April/May
- Immediately after harvest, but no later than early May, the cleaning of the palms must be initiated. Old fruitstalks, leaves touching the ground and young offshoots are to be removed since they stress the mother palm, cause its decline and decrease fruit yield. No direct planting of these offshoots should be practised; they must be rooted in the nursery for at least one year;
- Removal of spines from about 20 to 25 outside leaves and cleaning of the palms to prepare for pollination;
- Leaves with symptoms of diseases need to be removed and burned;
- Apply fertilisation on the 1st of April;
- Apply potassium chloride fertilisation on the 15th of April;
- Apply the ammonium sulphate fertilisation (in April and in May);
- If leaching is required, it must be practised before the start of the monthly fertilisation;
- The palm's basin is to be weeded and mulched; and
- Attend to the general maintenance practices such as inspection of all water points (drippers, microjets, etc.), mulching, weeding, repair of basins, etc.
June
- Apply the ammonium sulphate fertilisation;
- If male flowers start production, harvest the pollen and dry it;
- Monitor a control programme against pests and diseases (avoid the extensive use of chemicals and base your approach on Integrated Pest Management; manual or mechanical weeding, light traps, phenomone traps, removal of diseased leaves, etc.).
July
- Pollination season starts and will continue until the end of August, sometimes until the end of September;
- An adult male palm produces between 500 to 1,000 g of pollen (an average of 700 g), which is enough for pollinating 47 female palms; It is clear that 15 to 20 g of pollen is the required amount of pollen to be used per female palm; approximately 2 kg of pollen are needed per hectare.
- Germination and humidity tests of stored pollen could be initiated at any convenient located scientific facility; if this is not possible try to use only fresh pollen;
- Use mixed pollen (old and fresh); on daily basis, the pollen (just the quantity to be used) is to be mixed with non- perfumed industrial talc (or wheat fl ower) at a rate of 30 to 50 percent depending on varieties.
- Medjool only requires a low quantity of pollen (10 % pollen/talc ratio = 1:g);
- Only skilled labourers should be used for pollination;
- Pollination should only be practised between 10:00 in the morning and 15:00 in the afternoon (not before, nor after). A minimum temperature of 18°C is to be respected;
- If it rains within 2 to 3 days after pollination, repeat the pollination;
- To pollinate, the female spathes are to be gently opened after they start cracking; cover-sheaths will be removed with no damage to the inside fl owers;
- The top 1/3 of the female inflorescence should be removed (1st thinning); do not squeeze the inflorescences while doing this.
- Pollination should be applied at least twice with 2 to 3- day intervals (to ensure a good fruit set);
- In places where low temperatures are expected during the pollination season, craft paper bags are to be used to cover the pollinated infl orescence. Several days later (8 to 10), the bags must be removed.
- A slight leaf pruning could also be practised depending on variety and on the palm's canopy;
- Make sure that the future enlarged inflorescence is not disturbed by surrounding leaves;
- Apply the Maxi-Fos fertilisation on the 1st of July;
- Apply the ammonium sulphate fertilisation on the 7th of July.
- Apply the potassium chloride on the 15th of July.
August
- Continue pollination;
- Two weeks after the last pollination, ensure a passage in each palm and below each infl ores-cence in order to assess the fruit set and to position (if a leaf or two needs to be cut, it must be done at this time); this is to prevent wind/leaf damage on the fruits;
- Start marketing contact with potential date traders;
- Ensure the availability of packing material;
- Initiate logistical planning (storage, transport, etc.);
- Apply the ammonium sulphate fertilisation.
September
Six to eight weeks after the first pollination, start the following:
- Bunch removal: Limit the number of fruit bunches per palm to the accepted norms depending on the palm's age and vigour. Use the formula: an average of 10 leaves per bunch. The bunches kept are the ones with the nice fruit set and well equilibrated around the palm (equally distributed around the crown). One fruit bunch during first year of production, 2 bunches the second year, and so on.
- Bunch thinning: Thin from the inside (± 1/3) but do not cut too close to the remaining inside spikelets; leave 5 to 6 cm to avoid drying and fungal attack. Thinning is variety dependent and should be done only after precise evaluation of the fruit set;
- The above thinning techniques should always lead to the following fruit distribution:
* Barhee: 45 to 50 spikelets per bunch and 20 to 25 fruits per spikelet. The number of fruits per bunch will vary from 900 to 1,250; with an average of 15 g per fruit, the bunch weight will vary from 13.50 kg to 18.75 kg.
* Medjool: 30 spikelets per bunch and 10 fruits per spikelet. The number of fruits per bunch should be about 300; with an average fruit weight of 20 g (as a semi-dry fruit from 18 to 28 g), the bunch weight will approximately be 6 kg.
- Positioning and supporting the bunches: Immediately, after bunch thinning is fi nished at the whole plantation, the operation of positioning and tying is to be practised. Be careful to gently position the bunch in order not to break the fruitstalk (use both hands). Each fruit bunch should be supported (to avoid its future breakage) by the use of two ropes attached to the upper and the lower leaf.
Note that all the above practises (pollination, thinning, etc.) are labour intensive (170 working days/year/hectare), and must only be handled by skilled labour. It is necessary to treat the fl ower/inflorescence with care from pollination till Hababouk stage.
- Apply ammonium sulphate fertilisation.
October/November
- Apply the Maxi-Fos fertilisation on the 1st of October;
- Apply the ammonium sulphate fertilisation for October and November;
- All bunches are to be covered with net bags (80 %) to protect the fruits from birds, wasps and insects. This period should correspond to the passage of fruits from Kimri to Khalal. Fruits at this stage are starting to turn yellow in colour (case of Barhee variety) and the nets are to be left on the bunches till fruit ripening and harvesting. This protection operation must be completed throughout the whole plantation before the Rutab stage is reached.
December/January
- Observe irrigation programme;
- Apply the Maxi-Fos fertilisation on the 1st of January;
- Apply the potassium chloride fertilisation on the 15th of January.
February
- If necessary, all dried and half dried leaves could be pruned during February to avoid the Rutab fruits from damage caused by these leaves during windy situations. It also helps the harvesting operation.
- Before harvesting (February preferably), leaves that touch the ground can be removed along with small offshoots.
March
- Harvesting season depends on variety, location and care; it could start early February;
- Make sure that fruits are matured and correspond to market needs (maturation test); bunches are tested for export standards;
- Good management of harvest, transport to the packing house and packaging process.
General
- Leaf pruning can be summarised as follows:
* Immediately after harvest for the ones touching the ground;
* During the second thinning operation and while positioning the bunch, 1 to 2 leaves per bunch are to be removed if required, to leave free space for the fruit bunch; and
- Weeding around the palm needs to be practised on monthly basis;
- Microsprinklers or drippers and palms's basin need to be maintained on regular basis;
- Maintain mulching practices;
- Regular fi eld inspections for diseases and pests; and
- Plan in advence the labour requirements;
- Fertilisation Information
Table 45 listed in Chapter VI gives details about the fertilisation programme.
Figure 89. Date palm annual technical calendar: Model of Naute (Keetmanshoop), Namibia.
1) Minimum temperature statistics from 1948 till 1985 at Keetmanshoop Airport.
2) August wind direction: N-East and Sept/Oct/Nov: West (severe)
3) 15 February till 15 March is the best planting time(no wind, no extreme temperatures and humidity is relatively high - about 40%
4) Fertilisation and irrigation details are provided in chapter VI and VII, respectively.
