Root Zone Water, Salinity and Nutrient Management Under Precision Irrigation

Thu, 26 Jun 2008 05:01:39 +0000

IDs and People

Program:

National Program for Sustainable Irrigation

Legacy (KMS) Project ID:

SRD8

Host Organisation:

ACTION Salinity and Water

Researchers:

Dr Tapas Biswas

Subjects

Subjects:

Irrigation

Salinity

Soils

Monitoring and Assessment

Keywords:

Salinity Management

aquatic nutrients

Data and Information

Project Information

Summary:

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

Outcomes:

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.

Current Activities

Status:

Active

Background

Project Background:

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.

Aims:

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.

Tri-State Project - Impact of Salinity on Horticulture in the Lower Murray

Mon, 16 Jun 2008 22:40:13 +0000

IDs and People

Program:

National Program for Sustainable Irrigation

Legacy (KMS) Project ID:

DEP15

Host Organisation:

Department of Water Land and Biodiversity Conservation S.A.

Researchers:

Dr Gerrit Schrale

Subjects

Subjects:

Water (General)

Catchment Management

Field Crops and Horticulture

Irrigation

Salinity

Soils

Keywords:

aquatic nutrients

crops

Project Information

Summary:

The project, started in November 2003 and to finish in early 2007, is split into two stages and deliverables are spread over agreed milestones.

Stage 1: Specific tasks and main deliverables for Stage 1 are:

A detailed literature review of the salinity relationships for the commonly grown crops (grape, citrus, stone fruit, melon and vegetables) in the Lower Murray region;
Identify the knowledge gap in salinity relationships;
Explore the salinity implications of the leaching efficiency and its variance and prepare a focussed plan for field studies; and
Develop a framework for the economic assessment of the salinity hazard.

Stage 2: As a follow up of stage 1, the original project submission listed the following three main activities for stage 2:

Use chloride as a natural tracer in the soil profiles at suitable field sites (where the season’s irrigation practices have been recorded) to estimate leaching efficiency and its variance;
Use the models ‘VineLOGIC’ and ‘Swagman’ (for Citrus) to simulate salinity inputs versus outputs on selected vineyards and orchards; and
Assess the implications of the project outcomes in relation to the salinity and drainage management strategies.

The original submission identified that stage 1 findings may lead to revision of the stage 2 field investigations. It is now proposed that the stage 2 investigations also include field experimentation for measuring and subsequent modelling of the soil-water-plant-atmosphere transport processes.

An economic analysis was carried out on this project, looking at the following benefits: productivity and profitability; environmental; and social. Download economic analysis.

Outcomes:

The project is substantially improving our understanding of leaching efficiency and the amount of water required as a leaching fraction. The results of the project will inform the new NPSI project Root zone water, salinity and nutrient management under precision irrigation (SRD8).

Current Activities

Status:

Complete

Background

Project Background:

Irrigated horticulture in the Lower Murray (Riverland-Sunraysia) region contributes a ‘gate-value’ of about $ 2.5 billion a year to the national economy. As a consequence of improved irrigation practices over the years, there is a risk emerging of a salinity build-up in the root zone, threatening the sustainability of this region. During the past two decades the water use efficiency (WUE) of irrigated horticulture in this region has gradually increased from about 50 to 80% as a consequence of improved irrigation systems and management. With the objective to manage the irrigation impact on the river water quality and health of the floodplains, the River Murray Catchment Water Management Board introduced an 85% target of WUE in the current Water Allocation Plan.

In the Lower Murray Region the irrigation water salinity is typically about 0.4 dS m-1 and with 15% leaching the average salinity (ECe) in the root zone should be around 0.6 dS m-1. However field surveys indicate that the root zone salinity is often greater than 1.3 dS m-1 with considerable variance. In order to understand and manage this salinity hazard, a ‘Tri-State Salinity’ syndicate of Government agencies from western NSW, Victoria and South Australia (with support from federal agencies) was formed to undertake laboratory and field scale studies for irrigated horticulture in this region.

Aims:

To determine the salinity relationships for irrigated horticulture along the lower Murray: Riverland, Sunraysia and NSW
Determine the variance of EC (soil water) in the field under known soil conditions and irrigation management
Simulate the performance of the main crops under different scenarios of river salinity at Morgan
Provide input to the implementation of the Salinity Strategy and Integrated Catchment Management Plan of the Murray-Darling Basin and the Living Murray initiative.

Location

State & NRM Region:

New South Wales

Victoria

Locations:

Lower Murray

Riverland

Sunraysia

All in aquatic nutrients

Root Zone Water, Salinity and Nutrient Management Under Precision Irrigation

Tri-State Project - Impact of Salinity on Horticulture in the Lower Murray