Articles
Water use efficiency in high density planting trials with almond (Prunus dulcis (Mill.) D.A. Webb)
Article number
1406_21
Pages
145 – 152
Language
English
Abstract
Research trials in South Australia are comparing yields from almond blocks with 4.5-m and 6.5-m wide rows.
Planted in July 2018 with the new self-fertile cultivars ‘Vela’ and ‘Shasta®’ spring-budded onto ‘Nemaguard’ rootstock, the project is comparing planting densities of 513 (6.5×3 m), 769 (6.5×2 m), 741 (4.5×3 m) and 1,111 trees ha-1 (4.5×2 m). In 2021, kernel yields were 2.44 and 1.98 t ha-1 from third-leaf ‘Vela’ and ‘Shasta®’ trees, respectively.
Although higher yields were expected from the higher density treatments, there was no difference in yield per ha among the four spacings as irrigation had been applied on a per hectare basis (9.7 mL ha-1) rather than per tree (kL tree-1). If a treatment had twice as many trees per ha then each tree received half as much water from irrigation and produced half as much crop, thus negating the benefits of higher planting density.
In 2022, irrigation rates were adjusted to 17.1 mL ha-1 for the 4.5-m rows and 11.3 mL ha-1 for the 6.5-m rows.
This meant each tree at 2-m spacing received on average 15.1 kL for the year and each tree at 3-m spacing received 22.6 kL. With these irrigation rates, ‘Vela’ and ‘Shasta®’ trees at 2-m spacing produced on average 2.3 and 1.9 kg of kernel, and at 3-m spacing produced on average 4.0 and 2.8 kg, respectively.
Hence, more water equalled more crop.
There were minimal differences in tree size and sunlight was not limiting as trees were still young and not crowded.
Results are discussed in terms of water use efficiency and the irrigation requirements of young trees planted at high density.
Planted in July 2018 with the new self-fertile cultivars ‘Vela’ and ‘Shasta®’ spring-budded onto ‘Nemaguard’ rootstock, the project is comparing planting densities of 513 (6.5×3 m), 769 (6.5×2 m), 741 (4.5×3 m) and 1,111 trees ha-1 (4.5×2 m). In 2021, kernel yields were 2.44 and 1.98 t ha-1 from third-leaf ‘Vela’ and ‘Shasta®’ trees, respectively.
Although higher yields were expected from the higher density treatments, there was no difference in yield per ha among the four spacings as irrigation had been applied on a per hectare basis (9.7 mL ha-1) rather than per tree (kL tree-1). If a treatment had twice as many trees per ha then each tree received half as much water from irrigation and produced half as much crop, thus negating the benefits of higher planting density.
In 2022, irrigation rates were adjusted to 17.1 mL ha-1 for the 4.5-m rows and 11.3 mL ha-1 for the 6.5-m rows.
This meant each tree at 2-m spacing received on average 15.1 kL for the year and each tree at 3-m spacing received 22.6 kL. With these irrigation rates, ‘Vela’ and ‘Shasta®’ trees at 2-m spacing produced on average 2.3 and 1.9 kg of kernel, and at 3-m spacing produced on average 4.0 and 2.8 kg, respectively.
Hence, more water equalled more crop.
There were minimal differences in tree size and sunlight was not limiting as trees were still young and not crowded.
Results are discussed in terms of water use efficiency and the irrigation requirements of young trees planted at high density.
Authors
G. Thorp, A. Smith, M. Coates, R. De Bei
Keywords
irrigation, planting density, tree size, yield
Groups involved
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