ISHS Acta Horticulturae 792: V International Symposium on Irrigation of Horticultural Crops
USING REGULATED DEFICIT IRRIGATION TO MITIGATE DUST AND MAINTAIN OPTIMAL TREE WATER STATUS DURING ALMOND HARVESTS |
| Authors: | D.A. Goldhamer, M. Salinas |
| Keywords: | water stress, RDI, mechanical harvesting |
| Abstract:
Conventional almond [Prunus dulcis (Mill.) Webb] harvests involve mechanically shaking the nuts off the tree and drying the nuts on the orchard floor. These operations can produce large amounts of dust, which is a health hazard to both field workers and the public. Additionally, irrigation is often suspended during the conventional ground drying period to avoid wetting the nuts. Undesired tree water stress can occur and this may reduce the following season's fruit load. We are evaluating the use of regulated deficit irrigation (RDI) on cvs. 'Non Pareil' and 'Monterey' in a program that achieves "direct harvests;" on-the-tree drying (OTTD) of fruit and shaking the nuts directly into catching equipment. This harvesting approach eliminates ground drying and mitigates dust problems. We found that pre-harvest deficit irrigation accelerated the rate of hull split, allowing full hull split to be achieved 10 to 20 days faster than with full irrigation. The rate of OTTD nut drying was slower than with ground drying but the target pickup kernel hydration level of 5% occurred at about the same time due to the accelerated hull splitting with RDI. However, OTTD hull+shell moisture was 14% at pickup; somewhat higher than the target 9%. Additionally, individual dry kernel weight with RDI was reduced by 4 to 18% depending on the cultivar and stress level. Eliminating the ground drying allowed the OTTD irrigation to better maintain optimal post-harvest tree water status. This resulted in a mean increase of 8.3% in OTTD fruit loads the following season. These higher fruit loads offset the impact of reduced kernel size on yield. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
