A.D. Hirons, E.D. Elphinstone, I.C. Dodd, W.J. Davies
Nurseries use irrigation for the production of high quality containerised trees. Future climate scenarios suggest that water resources for irrigation are likely to become increasingly scarce in many regions. A survey of the major UK nurseries producing amenity trees, revealed significant opportunities to enhance current irrigation practices by adopting already accepted irrigation strategies. Novel irrigation techniques such as deficit irrigation (DI), which provides less irrigation than plant potential evapotranspiration and partial rootzone drying (PRD) which deliberately seeks to impose soil moisture heterogeneity within the soil volume, have been used in various plant production systems to improve water-use-efficiency (WUE). Irrigation was automatically scheduled using dielectric soil moisture sensors to maintain volumetric soil moisture contents between 30-40% and 20-30% in two different treatments. Within each of these treatments, two alternative water distribution techniques were applied; full water distribution (WW) which ensures the entire soil volume is watered evenly; and an alternate partial rootzone drying (PRD-A) which irrigates half of the soil volume (by halving the number of drippers in each container) whilst allowing the other half to dry. After 26 days of treatment, gas exchange data revealed that the leaf-level WUE of the trees had significantly increased under the PRD-A treatment. By day 47 significant reductions in net photosynthetic assimilation and stomatal conductance were observed in the PRD-A treatment. Any deleterious effects on leaf gas exchange were reversed within 7 days by returning to full irrigation (30-40% WW). These data may be used to help develop more sustainable approaches to irrigation and the management of water resources. DI may prove an important strategy for increasing the resilience of tree and woody ornamental nurseries as competition for water resources becomes more acute.
Hirons, A.D., Elphinstone, E.D., Dodd, I.C. and Davies, W.J. (2013). IMPROVING WATER USE EFFICIENCY IN TREE NURSERIES THROUGH DEFICIT IRRIGATION. Acta Hortic. 990, 331-338
DOI: 10.17660/ActaHortic.2013.990.40
deficit irrigation, irrigation scheduling, partial rootzone drying, tree nurseries, water use efficiency, Betula pendula

Acta Horticulturae