Root Zone Water, Salinity and Nutrient Management Under Precision Irrigation
The SRD8 project has an ongoing commitment to the development of salinity risk management strategies and tools designed to limit the damaging effects of salinity in the root zone, a fact that is most clearly represented by the establishment of 20 trial sites distributed through a range of growing conditions in SA, NSW and VIC.
Tapas Biswas, kneeling at centre, and SARDI researchers working with growers to achieve highly effecient water use and minimise root zone salinity. Photo: SARDI
The main objective of this new SRD8 project is to develop a salinity management strategy by including additional field studies on citrus orchards and vineyards on different soils (often more clayey) and high salinity water regimes.
In order to develop a salinity and nutrient management strategy for irrigated Horticulture the SRD8 project has been collecting data from 20 field sites across NSW, VIC and SA growing irrigated citrus, grapevines and tree nuts on different soils (often more clayey) and a range of water salinity regimes.
Real time data is being collected on irrigation and its system management, climate, chemical application, soil moisture and solution chemistry as well as plant nutrition and yield. These data are forming a valuable repository to underpin seasonal trends in water use efficiency WUE, deep percolation (leaching fraction), salt leaching and its efficiency, nutrient movement within the root zone and plant’s response to salt.
Data are also used for the calibration of the popular field water use model IRES (Irrigation Recording and Evaluation System), Van Genuchten-Darcy model for deep drainage estimation and solute transport models e.g., LEACHM-TRANSPORT and Hydrus).
In particular, this project includes the application of the DEP15 measuring and modelling techniques to surface and subsurface irrigated vines and citrus including citrus grown with advanced fertigation (e.g., Open Hydroponics) which may have a higher risk of water escape and nutrient leaching from the active rootzone. This involves comparative assessment of water, salt and nutrient movement between conventional and advanced fertigation systems.
Horticulture within the Murray Darling Basin other parts of Australia is facing one of its toughest tests of balancing improved water use efficiency and salt leaching since irrigation commenced in the late 1800’s. Growers need strategies to manage their crops under conditions of reduced water allocations together with the anticipated increase of irrigation salinity in future years.
Building on the Tri-State salinity project (DEP15), the SRD 8 project “Root Zone Water, Salinity and Nutrient Management under Precision Irrigation” aims to address these issues with particular reference to irrigated horticulture in the lower Murray regions.