Land and Soils
Why are land and soils important to us?
Soils are an important bio-physical asset. Soils in the region range from deep clay soils on productive agricultural floodplains to shallow skeletal soils in productive grazing plains of the west. The region’s soils are ‘old’ geologically and have comparative low nutrition and marginal productive capacity. Cropping land uses have developed in areas of better soils, e.g. brigalow soils and floodplain areas.
The restrictive nature of these soils limit land use options. Also, the highly fragile nature of the soils restrict land management options as well and in order to limit degradation, land managers need to apply less risky land management practices to those that are currently practised. Management practices that are responsive to a highly variable seasonal pattern are essential if they are to remain viable into the future.
In addition to these in-situ constraints, many of the soils and landscapes contain naturally high levels of salt that may begin to move if the water-related processes in the landscape change as a result of poor selection of land use and/or land management practice. The reversal of salinity impacts is a long process and it is timely to recognise a high salinity risk exists and has been delineated through salinity risk assessments. The extent of the salinity risk is represented in the figure below – Salinity Risk Map. This map shows areas with salinity levels where groundwater quality is occasionally half seawater and less than 10 meters deep and in some cases, rising. The Salinity Risk Assessment for the Murray Darling Basin Region (Biggs et al. 2010) provides the technical detail to inform management options. You can download a copy of this assessment from the QMDC website here: http://www.qmdc.org.au/land-water.html.
Salinity risk of the Plan region
As outlined in the ‘About the Region’ section of the Plan, a major land use in the region is pasture production from relatively natural environments. These areas comprise approximately 83% of the land area. Pasture areas support primarily beef cattle production, with secondary grazing uses of meat sheep, sheep for wool production and goats. It is likely the projected increased frequency of poor seasons will result in changes to grazing operations where breeding herds are substituted for more trade operations.
Production from dryland agriculture is principally derived from winter and summer cereal crops such as wheat, oats and sorghum. This area cropped comprises about 12% of the total land area, however, the area under cropping from year to year is directly related to seasonal conditions. Many of the cropping soils in the region have only a moderate to low plant available water capacity (PAWC), hence limiting planting windows to periods of moderate to good rainfall.
Irrigated cropping continues to occur on the floodplains of the Balonne River and Border Rivers catchment. The footprint on the total land mass is small, comprising around 2%. Irrigated crops in the region include cotton, some cereals, legumes and horticultural operations.
With regard to climate, the Agricultural Production System SImulator was used to model the effect of climate change projections on cropping systems in the region during the update of this Plan. The systems modelled include: monoculture wheat; monoculture sorghum; opportunity wheat and sorghum; and rainfed and furrow irrigated cotton. The objective of this work was to provide a broad indication of the relative effects of climate change in the major centres region and not to accurately reproduce broadacre cropping systems in these areas. You can view this work on TerraNova: https://www.terranova.org.au/repository/central-slopes-nrm-collection/apsim-output-for-climate-change-scenarios.
An enhanced adaptive capacity
Since 2004, the major rural industries of the region have developed management programs that are responsive to resource constraints and risk factors. The grains and grazing industries have developed best management practice (BMP) packages (QDAFF 2014c), the cotton industry has revised its BMP program (Cotton Australia 2014), grazing industry packages such as Grazing Land ManagementTM (GLM) (Quirk and McIvor 2005), and a range of commercially-developed products and schools also exist.
Landscape risk is considered as part of an ISO 14001 system (ISO 2004) adopted by the Certified Land Management System (ALM Group 2014).
Ecological Systems and Risk Management
The current land use pattern is supported by an ecology that is under threat. Large areas of grass/pasture in the region are suffering from decline in terms of composition and condition, large areas of soil are suffering from nutrient decline and condition decline, significant numbers and areas of vegetation are in decline, riverine condition is under threat and the most insidious threat is salinity across large areas.
The severity and extent of these ecological risks is intensifying, and will impact rural productivity. The management of these ecological risks through informed landscape management will be critical to the maintenance of the region’s natural asset base as it faces the impacts of a changing climate.
Incidence of natural disasters
The increased frequency and intensity of natural disasters in recent times has seen large areas affected by floods in 2011, 2012 and 2013. The area most severely impacted by floods is represented on the Flood Inundation Extent Map (Figure 9). The frequency of these events has impacted on the productivity and viability of farming communities. At the other extreme is the increased drought severity.
An improved understanding and management of these extreme climatic events and the effect that they have on assets is further considered in the Condition and Trend section of this asset.
Flood inundation extent map Queensland Murray-Darling Basin Region January 2011 flood event
Why are landscapes important to us?
The importance of landscapes