Projects and Programs

Cropping, Soils & Recharge

Background

This project is a joint project between the Lower Murray Darling Catchment Management Authority (LMD CMA), NSW Department of Primary Industries (NSW DPI) and Mallee Sustainable Farming Inc. (MSF). The project covers the rangelands and mixed farming areas of the Lower Murray Darling catchment area and aims at involving dryland cropping farmers with MSF Inc. through sampling and assessing their soils, improving their understanding and knowledge of soil health and groundwater recharge.

Activities include:

The project is subdivided into two parts salinity in the form of deep drainage and wind erosion.

Deep Drainage

Monitoring and recharge using ground water level changes is impossible to measure in a 10 to 15 year time frame as it takes several decades for water to move through the profile reaching the water table. Recharge in dryland areas can be measured using soil moisture and salts (chloride analysis) present in the profile. Soil moisture is measured using a neutron probe to a depth of 6 metres across 100 sites in the catchment area. Using soil moisture and chloride analysis, an estimate of recharge can be determined.

Wind Erosion

Wind erosion is the geomorphic agent that has the greatest potential to affect soil fertility and structure in the catchment as it removes topsoil, reduces the soil clay and silt content and reduces organic matter. Wind erosion also impacts on crop productivity by sandblasting emerging crops, reshapes the land-surface making it difficult to traverse with wide agricultural implements, buries or undermines infrastructure such as fences and roads and buries adjacent land with sand drift limiting the production of drifted lands. Wind erosion also has considerable off-site impact such as reducing visibility, depositing unwanted dust and associated contaminates off-farm and raises air-borne particulate levels with particle-sizes less than 10 micrometers (PM10), which can have adverse health effects.

Erosion risk/management practice measurements – paddock-based objective assessment that records management practices and the resultant soil cover and dry aggregation status. From this, erosion risk in 100 paddocks can be calculated. This method was used by the Mallee Sustainable Farming Inc. (MSF) and is being used by the Birchip Cropping Group (BCG) and the Victoria Direct Drilling Association.

Roadside erosion/land use survey – subjective visual assessments of 260 fixed points in cropping areas of the catchment. Management practices and wind erosion hazard and risk are recorded twice a year in December and March/April. This data set runs from 1999 and is comparable with other surveys in Victoria and South Australia.

DustWatch – regional monitoring of dust activity that using direct measures of dust concentration at six locations across the catchment, along with co-operating landholders who record and observe direction of the prevailing wind, visibility of a dust event, the colour of the dust, time and date of when the event occurred and whether or not it was localised or wide spread.

Modelling – numerical simulation of erosion and dust emission levels across the catchment.

The project is part of an on-going project until 2007.

Contact person:
Soils/Cropping Officer
Lower Murray Darling CMA
PO Box 363
Buronga NSW 2739
phone: 03 5021 9460
fax: 03 5021 1308