Effect of deficit irrigation on fruit growth and yield of mango (Mangifera indica, L.) in Northern Thailand
- Publikations-Art
- Zeitschriftenbeitrag
- Autoren
- Spreer W, Müller J, Hegele M, Ongprasert S
- Erscheinungsjahr
- 2009
- Veröffentlicht in
- Acta Horticulturae
- Band/Volume
- 820/
- Seite (von - bis)
- 357-364
- Tagungsname
- VIIIth International Mango Symposium
- Tagungsort
- Sun City (South Africa)
- Tagungsdatum
- 5.-10.02.2006
Although being one of few drought-tolerant plants of economic importance, mango trees are irrigated to ensure optimum and consistent productivity. Especially during the dry season, when water is becoming scarce, the need for irrigation poses an increasing problem to mango production in Northern Thailand. Therefore water saving irrigation strategies should help to decrease water consumption and hence improve the water shortage situation for local farmers. To investigate possible negative effects of deficit irrigation on yield and fruit growth, 196 ten-year-old ‘Chok Anan’ mango trees, at an experimental plot near Chiang Mai, Northern Thailand, were assigned to five irrigation regimes commencing two weeks after onset of flowering: a) full irrigation (FI) as calculated based on the climatic water balance according to the Penman-Monteith equation; b) deficit irrigation (DI) with 75% of FI (DI75); c) deficit irrigation with 50% of FI (DI50); d) partial root zone drying (PRD) with 50% of FI; and e) no irrigation. PRD is a novel irrigation technique presumably based on the induction of hormonal changes by targeted withdrawal of water to part of the root system, resulting in reduced stomatal aperture, decreased water consumption and reduced vegetative growth. Soil moisture was measured in three depths (10, 30, 50 cm) by Time Domain Reflectrometry (TDR). Stomatal closure was determined by use of a portable porometer. The yield was quantified gravimetrically per tree and classified into weight classes according to recommendation of the Thai Ministry of Agriculture. Fruit growth was monitored six weeks prior to harvest by measuring length and maximum width of the fruit. After two years of experiment the results showed a potential to increase water-use efficiency (WUE) of mango by deficit irrigation. Only in one year yield in PRD-irrigated trees was significantly lower than in FI trees. Especially in the second year there was no significant difference between DI50 and PRD. DI75 had the greatest yield, however not significantly higher than FI. Differences in yield were mainly attributed to the number of fruits per tree. In addition some positive influence of deficit irrigation, i.e. DI50 and PRD, on fruit growth could be monitored. As a conclusion it can be assumed, that the crop coefficient (Kc) for mango, which is commonly used to calculate potential crop evapotranspiration (ETc) based on the potential reference evapotranspiration (ET0), overestimates the water requirement for optimum yield.