New information about citrus fertigation
A major investment in research into improved methods of applying water and nutrients to citrus has resulted in an important contribution to the science in this area as well as techniques that can be applied by growers to improve their operations.
The research has been a fine example of collaboration involving researchers from two states (SA and NSW) with funding support from NPSI and Horticulture Australia Ltd.
The bulletin Guidelines for Fertigating Citrus and final report illustrate the benefits of fertigation and describes how to measure nutrient and water status, manage leaching, and other aspects. An associated study has been an economic assessment of open hydroponics.
Project: Preliminary investigations into open hydroponics irrigation for the citrus industry.
Research agency: South Australian Research and Development Institute (SARDI). Principal researchers – Tapas Biswas, Michael Treeby, Graham Trengove.
Advanced fertigation methods may lift profits
Open hydroponics is a fertigation management system that has the potential to significantly increase productivity and returns from citrus plantings. Because of the higher capital costs compared with traditional drip irrigation systems, economic as well as production outcomes were investigated.
It was a collaborative study, with funding from both the National Program for Sustainable Irrigation and Horticulture Australia Ltd, and participation of research personnel from SA (SARDI) and the NSW Department of Primary Industries.
Conventional fertigation involves adding a balanced amount of nutrient to the irrigation water. Open hydroponics simply incorporates more sophisticated monitoring of water and nutrient use with increased frequency of applications that target a smaller root zone volume. The smaller root volume served means water management is even more critical and time-consuming, with applications talking place often several times a day to maintain the best possible conditions for tree health and production.
Benefits of the more sophisticated system were found to be earlier fruit production from young trees, higher fruit production from mature trees and a higher percentage of fruit of the quality suitable for the fresh fruit market. The economic analysis revealed potential boosts to profitability from all these factors, with the advantage being reduced in the advent of severe water restrictions and reductions in fruit prices.
While there is a strong case for refining irrigation through open hydroponics, the investigators noted in their conclusions that in improving the productivity of any orchard, there is no substitute for good general management. They stated “It may well be possible to achieve an extra 10 to 15 tonnes of citrus/hectare from a poorly run orchard simply by improving general crop management rather that improving fertigation alone.”
For more infromation see the Impact of Open Hydroponics Irrigation in the Citrus Industry and Open Hydroponics: Risks and opportunities projects.
Other resources can be found on the NSW DPI web site: