Many farmers regard pecan nuts as a favourable long-term investment. Limit your risks and ensure that the high establishment costs reap rewards. Gunter Hollenbach explains.
Before pecan nut production can be established, farmers must first thoroughly investigate whether all the necessary requirements to produce high quality pecans have been met. Due to the high outlay costs it is crucial to make an informed decision.
Climate probably plays the biggest role in the quality of pecan nuts, which require a long, hot growing season. Low humidity is also important to produce a top-quality product. Most cultivars require that the tree experiences 200 to 220 frost-free days so that the nut quality and the ripening process are not affected.
In summer the daytime temperature should be between 28 to 36 °C and the night-time temperature from 14 to 24 °C. It is important that the night-time temperature doesn’t drop too low in summer as the tree is sensitive to cold in the growing season, while in winter it needs the cold.
It is essential that the temperature in winter drops below freezing so that the tree will go into dormancy and thus build up enough reserves for the coming growing season. Frost is needed in winter to speed up the ripening process and also to dry the nuts to an acceptable moisture level.
Soil is an important factor with permanent crops. The type of soil is not that important, but pecan nuts do better in loamy soil and the soil in which they are grown must be well-drained.
The soil can be well managed with various irrigation systems. Microjets are very effective in sandy soil, but in soil with a high clay content, drip irrigation should be considered. Loamy soil is highly suitable for pecan nuts and simplifies the watering regimen.
Pecans can be produced in soil with a pH of 5-8, but the ideal pH is between 5,5 and 6,5. Acid soil tends to exhibit deficiencies more readily than alkaline soil. Soil with a pH lower than 5,5 will result in poor root development.
Soil depth is very important for root development and also for distribution. A soil depth of at least 2m is necessary to grow pecan nuts effectively. Pecans are very sensitive to soil with a high saline content, some cultivars more so than others.
Water affects all aspects of pecan nut cultivation – from nut quality to yield – and is important for the transfer of nutrients in the soil. When it comes to pecans, it is important that water is well managed. Moisture must be monitored to ensure that water remains in the root zone for as long as possible because pecan nut trees absorb moisture better this way. If the trees are over-irrigated, nutrients are leached, oxygen is displaced and it results in waterlogging.
The moisture requirement for pecan nuts starts at around 50 litres of water per tree per day. A tree in full production (10 years old) can use up to 750 litres of water per day during the summer months. The usage will decline gradually towards winter. It is not recommended to cultivate pecans without irrigation. If pecans are grown without irrigation, the yield will be significantly less compared to orchards under irrigation.
The quality of the nuts will also be poorer, which will have significant ramifications on the profitability of the enterprise. Feeding roots are located in the top 600mm and this zone must be managed well to ensure the optimal uptake of nutrients and water.
The choice of cultivar plays a significant role in the profitability of the enterprise on account of the demand for certain cultivars on the international market. Pollinators must be established in the orchard.
The international market demands that the nuts have a minimum of a 55% kernel-to-shell ratio. The cultivars which produce larger nuts are more desirable in the international market. These cultivars include Choctaw, Mohawk and in some areas also Wichita. All these cultivars have pros and cons. Cultivars such as Pawnee and Navaho are used as cross-pollinators.
Certain cultivars thrive in warmer areas, while others prefer areas with a more moderate temperature. Some pecan nut cultivars are more resilient to plant disease. The cultivars that are mostly being planted currently are; Wichita, Choctaw, and the pollinator, Navaho.
The profitability of the enterprise and the establishment costs depend greatly on your orchard design (See TABLE). The direction of the rows is important to utilise the orchard volume effectively and to achieve the maximum yield per square meter.
Sunlight management in the tree plays a role so the rows must be planted in a north-south direction. This ensures that the tree gets enough light.
Gunter Hollenbach is team leader of pecan nut procurement at GWK
Contact Gunter Hollenbach on +2782 883 9652; email@example.com
|Row width||Number of trees per hectare||Benefit||Disadvantage||Total establishment costs: year 1 per hectare|
|10 m x 10 m||100 trees/ha||Mechanical pruning only required in year 12||Full production only reached in year 10||K44 220/ha R59 930/ha|
|10 m x 7 m||142 trees/ha||Full production achieved in year 8||Mechanical pruning must take place by year 9||K50 420/ha R68 330/ha|
|10 m x 5 m||200 trees/ha||Full production achieved in year 7||High establishment costs and tree thinning must take place in year 10||K58 980/ha R79 930/ha|
|12 m x 12 m||69 trees/ha||Low establishment costs.
Intercropping can be sustained for a longer period
|Full production is only achieved in year 12||K39 646/ha R53 730/ha|
|12 m x 6 m||138 trees/ha||Full production is achieved in year 8||Mechanical pruning must take place in year 8.||K49 830/ha R67 530/ha|