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Title: Investigation of partial rootzone drying in potatoes (Solanum tuberosum L.)
Author: Saeed, Hamad
ISNI:       0000 0001 3544 7273
Awarding Body: Harper Adams University College
Current Institution: Harper Adams University
Date of Award: 2008
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Limited water resources and legislation on water abstraction require the adoption of efficient irrigation techniques for sustainable crop production. Partial rootzone drying (PRD) is a technique that allows water use to be optimised through alternate cycles of irrigation to a split root system. A PRD regime and its optimum time of initiation in potatoes that reduces water use and improves water use efficiency with minimal loss in yield were investigated. Hydraulic redistribution mechanism and in-situ root growth responses to PRD were also studied. Potatoes (cv. Estima) were exposed to different irrigation treatments with a control at tuber initiation under polytunnel and glasshouse conditions to identify a suitable PRD regime for potatoes. The treatment which performed most similarly to the control was alternate PRD to field capacity (APRDlOo); one half of the root system was irrigated to field capacity, the other half was allowed to dry to 42 - 45 % of Fe, when irrigation was alternated between the sides. The alternate irrigation was continued until termination of the experiment. There were no significant differences between this treatment and the control for plant growth, gas exchange, leaf water potential and yield. This treatment utilised 29% less water and increased water use efficiency (WUE) by 20% relative to the control. The optimum start time of PRD in potatoes was identified by starting it at two, four, six, eight and ten weeks�·after emergence (WAE). Vegetative growth and yield increased with the delay start of the APRDlOo. When the APRDlOo was started at 6 WAE, greater water savings were seen with increased WUE compared to starting at 8 and 10 WAE but with no yield loss relative to the control. This suggested that the start ofPRD at 6 \VAE was an appropriate time for potatoes. Hydraulic redistribution from wet roots to drying roots within a 24 h period and over three days was investigated using the stable isotope of hydrogen. Hydraulic redistribution occurred the most at night when stomatal conductance was considerably lower and leaf water potential was higher (less negative). The magnitude of the redistributed water did not exceed 3.5%, indicating limited water redistribution under PRD. In-situ root growth responses to PRD showed that PRD plants maintained their root system by slowing down root growth during drying periods but resumed active growth upon re-watering. PRD appears to offer a suitable water saving technique for potato production in glasshouse conditions. Transferring this technique to field conditions, however, will need further research.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Potatoes--Growth ; Potatoes--Irrigation