Light interception and yield of sweet cherry and apricot trees grown as a planar cordon orchard system design
Orchard yield potential is understood to be proportional to mature canopy light interception. Consequently, productivity could be enhanced by increasing light interception. New planting systems for cherry and apricot trees are being investigated in New Zealand to increase yields of high quality fruit by increasing canopy light interception, using designs that reduce inter-row distances (alley widths). To allow adequate light distribution within the canopies with closer row spacings, tree forms with narrow planar canopies are required. These trees, planted 3 m apart in the row, comprise two cordons inclined ~20° above the horizontal and oriented along the row. Each cordon has six vertical minimally branched fruiting shoots spaced 25 cm apart, with a width of ~0.4 m, and an anticipated height of 3 to 3.5 m, arranged either vertically or as a narrow (~10-12°) V-canopy. Three cultivars each of cherry and apricot were planted at 2 m and 1.5 m inter-row spacings (1667 and 2222 trees ha‑1, respectively), both in a replicated design. The proportion of photosynthetically active radiation intercepted by these canopies at three-year-old (apricot) and four-year-old (cherry) was measured at full canopy in February 2018 (summer). This allowed investigation of planar cordon canopy row spacing effects and vertical- versus V-trellis effects on canopy light interception. Neither row spacing nor trellis system affected light interception or yield in cherries or apricots, or fruit quality in cherries, thus far. However, fruit quality of apricots was improved at the wider (2 m) row spacing. Light interception also was compared with four blocks of conventionally-grown trees at 666 and 883 trees ha‑1 for cherry and apricot, respectively. Light interception was 20-30% higher for the high density planar canopies than that of the lower density conventional central-leader systems of the same age. The planar systems also had more even light distribution than the conventional trees, suggesting that planar canopies may lead to enhanced productivity and fruit quality. Ongoing research will reveal canopy light relations in these planar canopies as the trees mature.
Scofield, C., Stanley, J., Schurmann, M., Marshall, R., Breen, K.C., Tustin, D.S. and Alavi, M. (2020). Light interception and yield of sweet cherry and apricot trees grown as a planar cordon orchard system design. Acta Hortic. 1281, 213-222
Prunus avium, P. armeniaca, PAR, irradiance, orchard systems, productivity