Review of mango irrigation research in the Northern Territory.
Bithell S. L., Diczbalis Y., Moore C.
Author Affiliation: Plant Industries, NT Department of Resources, GPO Box 3000, Darwin NT 0801, Australia.
: 60 pp.
Abstract : Mangoes (Mangifera indica) are the main horticultural crop in the Northern Territory (NT), Australia, grown mainly in the rural areas around Darwin and Katherine. The season's crop in 2009 was around 17?000 tonnes, valued at $46 m (Moore 2009). Water use efficiency (WUE) in horticultural production in the NT has become more important as the National Water Initiative leads to water-allocation planning and licensing. Information is required to improve WUE for economic and environmental outcomes. More than 10 studies have been conducted in the NT by the NT Government and CSIRO on irrigation or water use in mangoes. Most NT Government-led research results are presented in annual reports, while those of CSIRO are published in international scientific journals or presented at conference proceedings. The authors have attempted to present the key results of those studies in this Technical Bulletin. The aim is to provide a single source of information on past research on the use of irrigation in mango production in the NT, to evaluate past work to support improved WUE practices for mango growers and to identify future areas of research with the potential to improve WUE in mango production. It is intended that this information would be useful to those planning research and extension activities in this area and/or to those in need of information on water requirements for mango production. Studies on mango water use and irrigation covered a number of important areas, including determining pre-harvest irrigation cessation and season-long reduced volume applications on fruit quality; effects of irrigation at different phenological periods, including prior to flowering, and the effects of pre-flowering irrigation on trees receiving flowering-promoting treatments; the effect of age, season and variety on water use as determined by sapflow methods; different irrigation schedules on the efficiency of irrigation water use; and irrigation practices by growers. Key findings included the following points. Early cessation of irrigation prior to harvest often reduced fruit weight; fruit quality could also be negatively affected by the early cessation of irrigation. Paclobutrazol-treated trees tended to have higher yield if irrigated in the pre-flowering period. Pre-flowering water stress improved flowering and fruit production in non-paclobutrazol treated trees in Darwin. Monitoring at an irrigated site with 2030 L/tree/week applied in October indicated that the volume of water applied exceeded requirements. Water use in mango trees as indicated by sapflow was greater during the wet season. A dendrometer irrigation scheduling method gave a high irrigation efficiency of 77% compared with grower practices or 80% of pan evaporation replacement (31% and 38%, respectively).